National Institute on Alcohol Abuse and Alcoholism

FIVE YEAR

STRATEGIC PLAN

FY08-13

Alcohol Across the Lifespan

ALCOHOL ACROSS THE LIFESPAN

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U.S. Department of Health and Human Services

National Institutes of Health

National Institute on Alcohol Abuse and Alcoholism

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Table of Contents

Chapter I.
Overview

 

Chapter II.
Embryo and Fetus

 Chapter III.
Birth to Age Ten
 Chapter IV.
Youth and Adolescence
 Chapter V.
Young Adult
 
Chapter VI.
Midlife
Chapter VII.
Senior Adult

Mission and Vision of NIAAA

 

Background

 

Background

 

Definition of Youth and Adolescence

 Definition of Young Adult 

Drinking Patterns and Definitions

  
Epidemiology
  
Epidemiology
  
Epidemiology
  
Epidemiology
 
 
 

 

Prevalence of Alcohol Problems and Consequences

 Etiology  Etiology Biology  Biology  

Issues that Transcend Lifespan Perspective

 Prevention Prevention and Intervention Prevention Prevention and Treatment 

Alcohol Metabolism

 Treatment Opportunities Treatment  Opportunities 

Gene/Environment Interaction, Epigenetics

 Opportunities Outreach Opportunities Outreach 
Neurobiology Outreach   Outreach    
Diagnostic Criteria      Collaborations     
Alcohol Health Services Research         
 
          
 
          
 

NIAAA STRATEGIC PLAN

ALCOHOL ACROSS THE LIFESPAN

EXECUTIVE SUMMARY

Introduction

The National Institute on Alcohol Abuse and Alcoholism (NIAAA), a component of the National Institutes of Health, U.S. Department of Health and Human Services, is the lead agency in this country for research on alcohol abuse, alcoholism, and other health effects of alcohol. This document, the NIAAA Strategic Plan for Research, 2008-2013 sets forth a fundamental organizing principle for alcohol research studies and describes research opportunities to deepen and broaden our understanding of alcohol use and alcohol use disorders.

Alcohol use disorders (AUD) is defined as alcohol abuse and alcohol dependence, and arise from drinking too much, too fast and/or too often. Alcohol Abuse is defined as a recurring pattern of high-risk drinking that creates problems for the drinker, for others, or for society. Adverse consequences can also arise from a single instance of hazardous alcohol use. Alcohol dependence, typically considered to be synonymous with alcoholism (alcohol addiction), is a complex disease characterized by persistent and intense alcohol-seeking, which results in a loss of control over drinking, a preoccupation with drinking, compulsion to drink or inability to stop, and the development of tolerance and dependence.

The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recently came to similar conclusions about the toll taken by excessive alcohol use. According to the CDC, excessive alcohol consumption is the number-three cause of preventable death in the United States. The WHO also ranks alcohol third among preventable risk factors for premature death in developed nations. In 2003, the worldwide prevalence of alcohol use disorders (AUD) was estimated at 1.7%, accounting for 1.4% of the total world disease burden in developed countries. In the United States, 18 million Americans (8.5% of the population age 18 and older) suffer from alcohol use disorders. Only 7.1% of these individuals received any treatment for their AUD in the past year. Problems related to the excessive consumption of alcohol cost U.S. society an estimated $185 billion annually.

In addition to the adverse health effects that result directly from excessive alcohol consumption, other medical conditions often co-occur among individuals with excessive alcohol consumption. For example, alcohol abuse and dependence commonly occur in people who abuse other drugs, and in people with mood, anxiety, and personality disorders. An estimated 90% of cocaine addicts have alcohol problems and as many as 60% of patients at community mental health centers have alcohol and other drug abuse disorders. The high co-occurrence of alcohol and tobacco dependence poses special problems. An estimated 50% to 90% of alcohol dependent individuals are smokers who, in general, smoke heavily, become more addicted to nicotine and are less successful at quitting smoking than other smokers. This puts them at a much higher risk for certain cancers and cardiovascular diseases that develop more readily in the presence of both alcohol and nicotine.

Lifespan Perspective

Investigators traditionally have pursued solutions to the wide range of alcohol-related issues through studies of alcohol’s effects on biological systems, the genetic factors underlying these biological effects, and the environmental and cultural factors that influence alcohol use. This Plan applies a new organizing principle – the lifespan perspective – to these diverse areas of alcohol research. Scientists now recognize that human biology and behavior continues to change throughout life and changes occurring throughout the lifespan affect individuals' drinking patterns as well as the decisions they may make to change their drinking habits or to seek help for alcohol use problems. A lifespan perspective will allow researchers to identify how the emergence and progression of drinking behavior is influenced by changes in biology, psychology, and in exposure to social and environmental inputs over a person's lifetime, and vice versa. This approach should help researchers discover life stage- appropriate strategies for identifying, treating, and preventing alcohol use disorders.

Contributions to Alcohol Use and Alcohol Problems Across the Lifespan

Numerous factors influence the onset and continuation of alcohol use by an individual. The factors include the individual’s genetic makeup, the environments to which he or she is exposed and complex ways that genes interact with one another and with the environment. These same factors determine an individual's pattern of alcohol consumption and the risks for developing alcohol dependence (alcoholism).

Some of the first evidence of the importance of the lifespan perspective for understanding alcohol use disorders emerged less than ten years ago in an analysis of data derived from NIAAA’s National Longitudinal Alcohol Epidemiologic Study (NLAES). This analysis revealed that people who begin drinking at young ages have a significantly increased risk for developing alcoholism. This finding was confirmed by the recent National Epidemiologic Survey on Alcohol-Related Conditions (NESARC), which showed that young people who began drinking before age 15 are four times more likely to develop alcohol dependence during their lifetime than those who began drinking at age 21. This is true for individuals from families where a parent had a history of alcoholism and for individuals with no parental history of alcoholism. Therefore, while parental history clearly contributes to the risk for developing alcoholism, likely a reflection of genetic risk factors, early initiation of drinking is also an important predictor of risk for alcoholism. Researchers hypothesize that early exposure to alcohol may alter brain development in ways that increase an individual’s vulnerability to alcohol dependence. Some other biological factor, perhaps affecting personality, may also be responsible for both the early onset of drinking and the heightened risk for alcoholism.

Alcohol Policy and Public Health

A wide range of alcohol policies may affect alcohol consumption and other behaviors relating to alcohol, and can have important influences on public health outcomes. In the United States, laws, regulations, and jurisprudence address various aspects of alcohol use ranging from alcohol taxation to behaviors affected by alcohol, such as drinking and driving. Scientific research has identified a number of alcohol-related policies that have significant effects on public health outcomes. Examples of these include a reduction in the number of traffic fatalities (raising the minimum drinking age to 21, enforcing stricter drinking and driving penalties), a reduction in child abuse and sexually transmitted diseases (raising taxes on alcohol beverages), and enhancement of access to alcohol treatment programs (State-mandated provision in health care financing). In general, alcohol policies are designed to serve individuals at all levels of the lifespan through harm reduction and prevention of alcohol-related illness or injury.

Lifespan Perspective--Practical Implications

Understanding the interactions of alcohol with stages of life will enable us to address the prevention and treatment of alcohol problems in a life stage-appropriate manner. In particular, such an approach should lead to a better understanding of:
  • how alcohol perturbs development of the embryo and fetus, which may help reduce the impact of Fetal Alcohol Spectrum Disorders (FASD).
  • how genetic and environmental factors contribute to drinking initiation and the development of alcohol dependence, which will foster the rational design of prevention strategies that target specific risk factors at appropriate stages of the lifespan.
  • the factors that influence the common phenomenon of naturally “aging out” of alcohol dependence, to aid in the development of new therapeutic approaches and to help achieve behavioral change in alcoholism treatment.
  • how alcohol use produces functional and structural changes in the nervous system, which will aid in the development of behavioral and pharmacological therapies directed to specific molecular targets within the brain.
  • how the products of alcohol metabolism contribute to the development of alcohol-induced diseases of the liver, digestive system, lung, heart, brain, endocrine and immune system. Such knowledge could help develop better preventions and treatments for these disorders.

 

RESEARCH OPPORTUNTIES AND OUTREACH

The following is a brief outline of Research Opportunities and Outreach activities identified by NIAAA that will help guide the Institute’s research program and activities over the next 5 years.

Opportunities that Transcend the Lifespan Perspective

Several scientific issues have impact on all stages of life. While the manner by which they affect an individual may differ depending upon the person's stage of life, these issues are best considered from an overarching perspective and include: alcohol metabolism; genetic and environmental influences including epigenetics; neurobiological effects of alcohol; and improvements in the diagnostic recognition of alcohol use disorder.

Metabolism -- Individuals differ in how fast they metabolize alcohol and in the extent to which they are affected by a given dose of alcohol. These differences affect drinking behavior, the potential for the development of alcohol dependence, and the risk for developing alcohol-induced organ damage.

Alcohol and Gene/Environmental Interactions -- Neither genes nor environment alone can explain why any particular individual develops alcohol dependence. Rather, as a complex disorder, risk for alcohol dependence is a consequence of the interplay of multiple genes, multiple environmental factors, and the interaction of these genes and environmental factors. The alcohol field has benefited from the ability to model various aspects of alcohol consumption in animal models, but advances in our understanding of neurobehavioral aspects of drinking and its consequences requires the development of new models. The identification of a number of genes contributing to the vulnerability to alcohol dependence in human studies, coupled with technological advances including the ability to conduct genome-wide association studies, offer great promise to further define genetic risk factors and their interactions with environmental factors.

Epigenetics -- Metabolic and environmental factors can influence the manner in which genes are expressed through a process known as epigenetics. Epigenetics refers to stable alterations in the genome, sometimes heritable through cell division, that do not involve the DNA sequence itself. Epigenetic processes act as an additional source of biologic variation beyond that attributable to the genetic code. These processes involve the chemical modification of the constituents of the chromosome, the DNA molecules and the gene-regulating proteins known as histones, and may occur as a consequence of exposures to specific environmental substances and stimuli.

Neurobiology -- The brain, which is the primary target for alcohol-induced neurotoxic effects including alcohol dependence, continues to develop and mature from conception through birth into early adulthood. Alcohol consumption may affect the normal physiology of the central nervous system at any point throughout the lifespan, and those effects may differ depending on lifespan stage.

Diagnosis of Alcohol Use Disorders -- While the diagnostic criteria for alcohol dependence and alcohol abuse provided in current diagnostic schemes, including the DSM-IV and ICD-10, have contributed to improved case recognition and served researchers well over the past decade, research has begun to focus on developing quantitative representations of these criteria using statistical methods that provide differential severity weighting for individual AUD symptoms and allow for the inclusion of alcohol consumption variables. The development of quantitative criteria will lead to better understanding of the pathological stage of the disease for any given individual, provide the researcher an improved understanding of the etiology of alcohol dependence, and augment translational research to develop improved treatment approaches for the differing severity levels of alcohol dependence.

Alcohol Health Services Research--Alcohol health services research is a multidisciplinary field of applied research that seeks to improve the effectiveness, efficiency and equity of services designed to reduce the public health burden of alcohol use disorders across the lifespan. It does this by examining how social factors, financing systems, service environments, organizational structures and processes, health technologies, and personal beliefs and behaviors affect access to and utilization of healthcare, the quality and cost of healthcare, and in the end our health and well-being. Ultimately the goal of alcohol health services research is to identify ways to organize, manage, finance, and deliver high-quality care conistent with developmental needs of patients and their families.

Opportunities: Embryo and Fetus

The earliest stages of life are periods of great vulnerability to the adverse effects of alcohol. Embryonic and fetal development are characterized by rapid, but well-synchronized patterns of gene expression, including epigenetic imprinting, which makes the embryo/fetus particularly vulnerable to harm from alcohol, a known teratogen (an agent capable of causing physical birth defects). Alcohol's teratogenic effects were recognized over three decades ago, and it is now the leading known environmental teratogen. Alcohol may also damage neurological and behavioral development even in the absence of obvious physical birth defects. Alcohol-induced birth defects are known as fetal alcohol spectrum disorders (FASD). The severity of defects depends on the dose, pattern, and timing of in utero exposure to alcohol. Research in animal models has demonstrated that the potential for adverse effects increases with the maternal blood alcohol concentration (BAC). Research has also suggested that alcohol's causative role in FASD can be influenced by maternal hormones, nutrition, age, parity, years of drinking, and genetic factors. The most serious adverse consequence of prenatal alcohol exposure is fetal alcohol syndrome (FAS), a devastating developmental disorder characterized by craniofacial abnormalities, growth retardation, and nervous system impairments that may include mental retardation. Children and adults with FAS have irreversible neurobiological deficits that affect multiple systems, ranging from motor control to executive function.

Outreach: Embryo and Fetus

Opportunities: Birth to Age Ten

A number of significant research opportunities and directions exist for the birth to age ten years group. The first two are very high priority since there is little to no information in these areas. The third is also a very high priority as there is a need to better understand why drinking is a normative behavior among American adolescents and how drinking becomes so widespread among youth. The remaining opportunities represent areas where increased knowledge about known developmental pathways into alcohol use and AUDs will enhance prevention efforts with specific groups of youth at high risk.

In some cases, familial, neighborhood, and peer structures act in concert to encourage the development of early involvement with alcohol. Determine the degree to which these concurrent risk factors are synergistic for the development of risk.

 
Outreach: Birth to Age 10

Opportunities: Youth/Adolescence

The beginning of adolescence is demarcated biologically with the onset of puberty, and is understood to end when an individual assumes adult roles and responsibilities. Puberty consists of many biological processes that do not occur at the same chronological age and do not necessarily progress at the same pace or have the same pattern of unfolding in every individual. Importantly, brain development, marked by continuous generation of neurons and connections between neurons, and the refinement of communication among those neurons, continues during puberty and into the young adult ages. Drinking alcohol during this dynamic period of brain development may result in brain effects leading to an earlier onset of alcohol-induced specific diseases or to an earlier transition towards the development of alcohol use disorders. Very important to understanding alcohol use by youth from a developmental perspective is the fact that, over the past 100 years, the endocrine changes associated with puberty have been occurring at younger ages, while the attainment of adult roles such as starting a career, finding a partner, owning a home and becoming a parent are occurring much later. The result is the dramatic expansion of the period referred to as adolescence which prolongs the potential duration of one of the heaviest drinking periods of the lifespan and therefore may exacerbate the harmful effects on alcohol on development. In sum, adolescence is a period of dramatic biological change -- occurring in the context of equally dynamic socio-environmental change with regard to the adolescent's school, peer group, family, and social milieu. The majority (80%) of youth begin to drink by the end of high school, and some experience significant alcohol-related problems including the development of alcohol use disorders.

Outreach: Youth/Adolescence

Opportunities: Young Adult

Entry into young adulthood is defined by a variety of self-directed transitions that signal an individual's burgeoning independence from parental care. The pursuit of post-secondary education, enlisting in the military, and entering the workforce are a few such milestones, which traditionally have occurred when an individual is in his or her late teens or early twenties. Other events that traditionally mark this period include assuming large financial obligations, courtship, and marriage. In the U.S, most states have adopted age 18 as the legal age of majority – the point at which individuals assume responsibility for their own actions. However, from a developmental rather than a legal perspective, emerging or young adulthood now comprises an extended period of unsettled behavior for many individuals, as age of marriage and age of career initiation in the U.S., for example, have increased relative to historic norms. Compared to all other age groups, the prevalence of periodic heavy or high-risk drinking is greatest among young adults aged 18 to 24. Alcohol use disorders including alcohol dependence (alcoholism), also peak during this period. While most young adults transition out of harmful drinking behaviors, a minority will continue to drink heavily into the later stages of adulthood. These phenomena raise important research questions. For example, what factors allow some young adults to discontinue harmful drinking patterns, most often in the absence of formal alcoholism treatment? Why do others experience protracted alcohol problems well into their adulthood?

Outreach: Young Adult

Opportunities: Midlife

A broad spectrum of alcohol-related problems and issues becomes manifested during the adult period of life often referred to as midlife. At midlife, many of the pathological consequences of heavy alcohol use become most evident, and individuals with alcohol dependence are most likely to seek treatment of their alcoholism at this time.

Metabolism and Organ Injury

Alcohol and HIV/AIDS

Treatment and Behavioral Change

Medications Development

Outreach: Midlife
 

Opportunities: Senior Adult

Aging is associated with a variety of changes that place senior adults at special risk for alcohol-related health problems. Senior adults are known to differ in their physiological and behavioral responses to alcohol in a variety of social contexts, and their ability to develop tolerance to alcohol is greatly altered during the senior years. Drinking can aggravate a variety of pathological conditions in the senior adult including stroke, hypertension, neurodegeneration, memory loss, mood disorders, and cognitive or emotional dysfunction. As the percentage of persons in the senior age category is rapidly growing in the United States, improving knowledge about the effects of alcohol at this life stage is becoming increasingly important.

Outreach: Senior Adult

Top

 

CHAPTER I. OVERVIEW

The National Institute on Alcohol Abuse and Alcoholism (NIAAA), a component of the National Institutes of Health, U.S. Department of Health and Human Services, is the lead agency for U.S. research on alcohol abuse, alcoholism, and other health effects of alcohol. Its role is enunciated in the Institute Mission Statement:

A. Mission and Vision of NIAAA

The NIAAA Mission is to provide leadership in the national effort to reduce alcohol-related problems by:

The Institute's efforts to fulfill its mission are guided by the NIAAA Vision to support and promote, through research and education, the best science on alcohol and health for the benefit of all by:

This document, the NIAAA Strategic Plan for Research, 2008-2013, sets forth research opportunities to increase our understanding of why, how, and when people drink, as well as why and how some people develop alcohol use disorders (AUD). Throughout the years, investigators have pursued answers to these very questions through studies of alcohol’s effects on biological systems, the genetic factors underlying biology, and through the study of environmental and cultural factors. This Plan, however, proposes a significantly different direction for alcohol studies by applying the lifespan perspective -- the consideration of how the emergence and progression of drinking behavior is influenced by multiple changes (in biology, psychology, and in exposure to social and environmental inputs) over a person’s lifetime. These changes occurring throughout the lifespan affect the pattern of drinking (quantity and frequency) and the actions individuals may take to modify their drinking behavior or to seek help for an alcohol use disorder. Viewing alcohol use and alcohol problems through a lifespan perspective will provide knowledge that will, through early identification and intervention, significantly contribute to the ability to decrease the prevalence of alcoholism and other alcohol-related disorders, and to the treatment of these disorders.

This overview describes the origins of the lifespan perspective, highlights the complexity of alcohol issues in health, and provides a view to why solutions to these problems cannot be approached from any single discipline but must be approached in a multidisciplinary and transdisciplinary manner. Further, the findings at any investigative level (molecular, cellular, animal model, human laboratory, human clinical to community) must be translated to other levels and eventually to clinical practice in the world environment. Transdisciplinary and translational research over the course of the next decade will be aided by the intellectual and technical developments arising from the NIH Roadmap and the NIH Neuroscience Blueprint, and their potential application to address health issues related to alcohol use has been integrated into this Plan.

B. Drinking Patterns and their Definitions

An understanding of the drinking patterns that exist in the population, as well as the alcohol-use disorders that arise from drinking too much, too fast and/or too often, is important for identifying targets for future research pursuits.

Alcohol Abuse and Alcohol Dependence are two clinical disorders characterized by either a persistent pattern of inappropriate alcohol use or of adverse consequences. Alcohol dependence is typically considered to be synonymous with alcoholism. Alcohol abuse and alcohol dependence may be defined as shown in Tables I-1 and I-2. A proposal has recently been made to use the term addiction to specify the behavioral, CNS neuroadaptive responses to chronic alcohol exposure vis a vis loss of control, preoccupation with drinking and compulsion to drink, as distinct from the physiological dependence symptoms of tolerance and withdrawal.

Table I-1. Harmful or Hazardous Alcohol Use (Alcohol Abuse)

A recurring pattern of high-risk drinking that result in adverse outcomes, including:

* Personal problems: memory and cognition; job, family, friends, and other significant relationships; health and organ damage
* Problems to others: injury and death; violence and crime (property damage, assault, homicide)
* Problems for society: underage drinking; health care costs; economic productivity
* Use in hazardous situations

 

Table I-2. Alcohol Dependence (Alcoholism)

A complex disease characterized by a persistent and progressive pattern of abnormally intense alcohol-seeking behavior that, over time, results in:

* loss of control over drinking
* a preoccupation with drinking
* compulsion to drink/unable to stop
* the development of tolerance or dependence

 

While recurrent or persistent harmful or hazardous alcohol use results in adverse consequences in the long-term situation, adverse consequences can occur in individuals who may have used alcohol in a harmful or hazardous manner on only one occasion. These adverse consequences include alcohol-related traffic crashes, drownings, and alcohol poisonings, among many others.

Drinking in a manner that will cause intoxication clearly poses risks to the drinker. A term frequently used to describe this pattern is binge drinking. Different definitions often have been used for this pattern of drinking. To provide clarification, the National Advisory Council on Alcohol Abuse and Alcoholism (NAC) in 2004 developed a standard definition for binge drinking as a pattern of drinking alcohol that brings the blood alcohol concentration to 0.08 gram percent (the legal limit for drinking and driving in all states) or above. The NAC further noted that for a typical adult male, this BAC level may be obtained after the consumption of 5 drinks in a 2 hour period, and for females, 4 drinks in the same period. The Council definition of binge drinking and recommendations are provided in Table I-3.

Table I-3. Definition of Binge Drinking

 

A "binge" is a pattern of drinking alcohol that brings blood alcohol concentration

(BAC) to 0.08 gram percent or above. For the typical adult, this pattern corresponds to consuming 5 or more drinks (male), or 4 or more drinks (female), in about 2 hours. Binge drinking is clearly dangerous for the drinker and for society.

* In the above definition, a "drink" refers to one serving of 12 g of absolute alcohol (e.g., one 12-oz. Beer, one 5-oz. glass of Wine, or one 1.5-oz. Shot of distilled spirits).
* Binge drinking is distinct from "risky" drinking (reaching a peak BAC between .05 gram percent and .08 gram percent) and a "bender" (2 or more days of sustained heavy drinking).
* For some individuals (e.g., seniors or people taking other drugs or certain medications), the number of drinks needed to reach a binge level BAC is different than for the "typical adult".
* People with risk factors for the development of alcoholism have increased risk with any level of alcohol consumption, even that below a "risky" level.
* For pregnant women, any drinking presents risk to the fetus.

* Drinking by persons under the age of 21 is illegal.

Source: NIAAA, National Advisory Council, February, 2004

Binge drinking is common across most life stages. Fifty percent of college students who drink engage in binge drinking, and twenty percent do so twice or more every three weeks. More than two-thirds of binge drinking episodes in the U.S. occur among adults age 26 and older, and half of all binge drinking episodes occur among people who otherwise drink moderately.

The NIAAA also provided a definition of moderate drinking as this term has been used in many different ways. Moderate drinking is defined by the NIAAA as consuming up to two drinks per day for men and one drink per day for either women or senior adults. While moderate drinking is considered to offer some benefits to some individuals, drinking at this level poses real risks for others. For example, women who are pregnant or considering pregnancy, persons driving or operating heavy machinery, and those taking one or more of the more than 150 medications that interact with alcohol should not drink even moderately. Persons with a high vulnerability to develop alcohol dependence may be encouraged to refrain from alcohol use.

The National Epidemiological Survey on Alcohol and Related Conditions (NESARC) study completed its first wave of data collection, which involved recording the responses to questions posed to over 43,000 individuals about alcohol and other drug use, abuse and dependence, and their associated disabilities. These data were used to develop extremely valuable information relating quantity and frequency of alcohol use to the risk of developing alcohol abuse and alcoholism. These data have been used to establish the following cut points for risk drinking, which mirrors the definition for moderate drinking: Exceeding 2 drinks per day for men, 1 drink for women, and 14 drinks per week for men and 7 drinks per week for women. The NESARC data revealed that, compared with individuals who adhere to the weekly and daily limits, those who exceed only the weekly limits have an 8-fold increase in risk for developing alcohol abuse and a 12-fold increase in risk for becoming alcohol dependent at some point in their lives (Table I-4). Exceeding daily limits once a week or more increases risk for alcohol abuse by 30-fold, and for dependence by 80-fold. Exceeding both weekly and daily limits increases the risk of alcohol dependence by more than 200-fold.

Table I-4. U.S. Adult Drinking Patterns and Risks 2001-2002: Odds Ratios
Adult Drinking Patterns and Risks
Source: NIAAA 2001-2002 NESARC data

C. Prevalence of Alcohol Problems and Their Consequences

How extensive are the health problems arising from inappropriate alcohol use and what are those problems? Excessive, long-term alcohol consumption can cause a variety of adverse health effects, including alcoholic liver disease, alcoholic pancreatitis, brain damage, and cardiomyopathy and compromised immune and endocrine functions. Excessive drinking is also associated with an increased risk for cancers of the esophagus, liver, and larynx, irregular heartbeats, and can exacerbate the health consequences of infection with hepatitis C, HIV and other infectious agents. Alcohol consumption can also alter neuronal function, resulting in cognitive deficits, and in neuroadaptations that contribute to the behavioral changes observed with alcoholism (tolerance, sensitization, loss of control, dependence, withdrawal, and relapse).

Epidemiologic data inform us of the problems associated with alcohol consumption and, when collected over time, allow us to track our progress in addressing these problems. The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recently came to similar conclusions about the toll taken by alcohol misuse. According to the CDC, excessive alcohol consumption is the number-three cause of preventable death in the United States. The WHO also ranks alcohol third among preventable risk factors for premature death in developed nations. The extent of the alcohol use disorders problem in the U.S. and worldwide is summarized in Table I-5.

Table I-5. Extent of the Alcohol Use Disorder Problem

Globally:

* In 2003, the prevalence of alcohol use disorders was estimated at 1.7%, accounting for 1.4% of the total world disease burden in developed countries

United States:
* 18 million Americans (8.5% of the population age 18 and older) suffer from alcohol abuse or dependence. Only 7.1% of these individuals received any treatment for their alcohol problems in the past year.
* Alcohol problems cost U.S. society an estimated $185 billion annually

* Alcohol was the third leading cause of death in the US in 2003 (an estimated 85,000 deaths)

Source: World Health Organization, 2003

Alcohol also contributes significantly to mortality from a wide-range of acute and chronic injuries and diseases (see Table I-6). In the U.S. in 2001, 75,766 deaths were attributable to alcohol, 40,933 deaths were attributable to acute conditions primarily unintentional injuries such as motor vehicle injuries, and fall injuries, and intentional injuries such as homicide and suicide, and 34,883 deaths were attributable to chronic conditions especially alcoholic liver disease and liver cirrhosis. Because alcohol attributable deaths resulting from acute conditions occur earlier in the life span than chronic alcohol attributable deaths, they account for nearly twice as many years of productive life lost (e.g., 1,491,317) compared with chronic alcohol attributable deaths (e.g., 788,005). Recently, the NIAAA Extramural Advisory Board (EAB; a working sub-group of the NIAAA National Advisory Council) recommended that researchers could improve the estimation of alcohol-attributable factors (AAF) for morbidity and mortality by better characterizing the relationship between patterns of drinking (e.g., binge-drinking) and a variety of outcomes, and by incorporating relevant indicators of drinking (e.g., medical examiner data).

Injuries are the leading cause of death in the U.S. from ages 1-44, and alcohol is the leading contributor to those injury deaths. It should be noted that many people who die from alcohol attributable injury deaths are persons other than the drinker. For example, 40% of people who die in crashes involving drinking drivers are persons other than the drinking driver e.g. passengers in the same vehicle, passengers in vehicles struck by the drinking driver, bicyclists and pedestrians. Further, many homicide victims are fatally injured by persons who had been drinking. This underscores the need to identify, through rigorous research programs, policies that protect individuals from their own excessive drinking, as well as from the potential harms excessive drinking may cause society. One manner in which to get some indication of how policies affect excessive alcohol consumption leading to harm would be to undertake systematic studies of key alcohol and other relevant public policies and their outcomes (Recommendation of the NIAAA EAB, August 2006).

Table I-6. Number of deaths and years of potential life lost (YPLLs) attributable to the harmful effects of excessive alcohol use for selected conditions, by cause and sex – United States, 2001

 
Deaths
YPLLs
 
CauseMaleFemaleTotalMaleFemale Total
Chronic conditions
     
Acute pancreatitis

370

364 7347,1386,05413,192
Acute cardiomyopathy
443
5649910,1951,552 11,747
Alcohol-induced chronic Pancreatitis

224

71
295
6,2092,1358,344
Alcoholic liver disease8,9273,27412,201221,36994,952
316,321
Chronic pancreatitis
126
106
232
2,606
1,952
4,560
Esophageal cancer
394
53
447
6,213
788
7,000
Liver cancer
518
172
690
8,640
2,633
11,273
Liver cirrhosis, unspecified3,9172,802 6,71980,61654,528135,144
Oropharyngeal cancer
303
57
360
5,280
889
6,169

Total

24,448 10,28534,883549,396239,619788,005

Acute conditions

      
Alcohol poisoning
253
78
331
8,798
2,952
11,750
Homicide5,963
1,692
7,655262,37971,543333,922
Motor vehicle 10,674
3,000
13,674442,943136,558579,501
Suicide
5,617
1,352
6,969186,56849,297235,865
Falls
2,500
2,206
4,766
41,627
24, 288
65, 914
Total Acute Conditions30,30910,53440,9331,131,028350,2891,491,397

Total

54,94720,91875,7661,679,414599,9082,279,322

Source: Adapted from the table in Alcohol-Attributable Deaths and Years of Potential Life Lost --- United States, 2001 MMWR September 24, 2004, 53;866-870.

Co-Morbid Conditions

In addition to the many adverse health effects that result directly from alcohol misuse, co-morbid conditions often present further complications for individuals with alcohol abuse problems. Alcohol abuse and dependence commonly occur in individuals who suffer from mood, anxiety, and personality disorders as well as the effects of other drugs of abuse, (see Table I-7). For example, an estimated 90% of cocaine addicts have alcohol problems. It also has been estimated that as many as 60% of patients presenting at community mental health centers have co-morbid alcohol and other drug abuse disorders. Patients suffering from both disorders often have poorer treatment outcomes and are more likely to drop out of treatment. Unfortunately, effective pharmacological and behavioral treatments have yet to be established for the various conditions of co-morbid AUD and other drug abuse disorders.

The high co-morbidity between alcohol and tobacco dependence poses special problems. Fifty to ninety percent of alcoholics smoke, a rate that is three times higher than among the population as a whole. Alcoholics smoke heavily, are more addicted to nicotine and are less successful at quitting smoking, which puts them at a greatly increased risk for the synergistic effects of alcohol and nicotine on the development of certain cancers and cardiovascular diseases. According to one study, more individuals with alcoholism die from smoking-related diseases than alcohol-related diseases. Furthermore, there is experimental evidence that smoking may lead to a reduction in blood alcohol concentration for a given amount of alcohol consumed, thus leading to an increased use of alcohol to achieve the same pleasurable feelings from alcohol ingestion. Thus, smoking increases the amount of alcohol consumed and subsequently the risks for short-term and long-term adverse effects from the increased consumption of alcohol, including the perpetual cycle of use leading to dependence on both substances. Finally, there is evidence to suggest that the brain pathways that underlie the pleasurable feelings derived from alcohol consumption and smoking are thought to be the same, thus accounting for the increase in use of both substances, which suggests that treatment programs to reduce or cease alcohol consumption should also address cessation of smoking. There are some data indicating that treating one use disorder without treating the other concurrently leads to a higher relapse rate for either substance.

Table I-7. Odds of Current (past 12-month) DSM-IV Alcohol Dependence Co-Occurring with Selected Psychiatric Conditions and Other Drug Dependencies Odds of Current (past 12-month) DSM-IV Alcohol Dependence Co-Occurring with Selected Psychiatric Conditions and Other Drug Dependencies

 

 

 

 

 

 

 

 

 

 

 

Source: NIAAA 2001-2002 NESARC data

Contributions to Alcohol Use and Alcohol Problems Across the Lifespan

The initiation and continuation of alcohol use by an individual is influenced by numerous factors, chiefly the individual's genetic makeup, the environments to which he or she is exposed, and complex mechanisms through which genes interact with one another and with the environment. These same factors determine an individual's pattern of alcohol consumption and the risks for developing alcohol dependence (alcoholism) or other alcohol use disorders.

More than three decades of research has firmly established that genes account for more than half of the risk for alcoholism and environmental factors account for the remainder. This statement, however, belies the true complexity of the mechanisms underlying the risk for, and protection against, alcohol abuse and alcohol dependence. As with many other complex diseases, there is no single genetic or environmental factor that can fully account for the risk of alcoholism. The development of such complex behavioral and other medical disorders likely depends upon the specific genetic factors interacting with one another, the interaction of multiple environmental risk factors, and the interaction of genetic and environmental factors.

Research has also revealed that neither genetic nor environmental factors are static. That is, the emergence and progression of drinking behavior and of drinking consequences is influenced by multiple ongoing changes in biology, physiological and psychological development, and environment that occur over the course of a person's life. These observations are in accord with a broader recognition that human development continues throughout life, rather than stopping after adulthood is reached. A full understanding of the development of drinking behaviors and disorders, therefore, requires a lifespan context, in which the central concept is that the influence of alcohol on biology and behavior is dynamic and changes as an individual moves from childhood into adolescence and through the various stages of adulthood. This conceptual framework is depicted schematically in Figure I-1.

Figure I-1. Alcohol Across the Lifespan

Alcohol Across the Lifespan

Some of the first evidence of the importance of the lifespan perspective for understanding alcohol use disorders emerged less than ten years ago in an analysis of data derived from NIAAA’s National Longitudinal Alcohol Epidemiologic Study (NLAES). This analysis indicated that persons who begin drinking at younger ages have a significantly increased risk for the development of alcoholism. This finding was replicated in the recent NESARC study, as shown in Figure I-2. These data show that young people who begin drinking before age 15 were four times more likely to develop alcohol dependence during their lifetime than those who begin drinking at age 21. This is true for individuals from families where a parent had a history of alcoholism (Parental History Positive) and for individuals with no parental history of alcoholism (Parental History Negative). Therefore, while parental history clearly contributes to the risk for developing alcoholism, likely a reflection of genetic risk factors, early initiation of drinking is also an important predictor of risk for the eventual development of alcoholism.

Figure I-2. Prevalence of Lifetime Alcohol Dependence by Age of First Alcohol Use and Parental History of Alcoholism

Prevalence of Lifetime Alcohol Dependence by Age of First Alcohol Use and Parental History of Alcoholism

Source: NIAAA 1991-1992 NLAES data (left panel) and NIAAA 2001-2002 NESARC data (right panel)

What is the mechanism by which exposure to alcohol in youth or adolescence increases the risk for alcoholism? Early exposure to alcohol may alter neurodevelopment through one or more mechanisms to cause increased vulnerability to alcohol dependence. Alternatively, it is possible that some other biological factor, perhaps affecting personality, is responsible for both the early onset of drinking and the heightened risk for alcoholism. As research continues, new findings will help to establish how, and the extent to which each of these two potential mechanisms contribute to the development of alcohol problems. That knowledge will arise from research on brain development in general, as well as from research directed specifically to alcohol-related issues. For example, research on human brain development has revealed that the brain continues to develop through adolescence and into young adulthood. Research also has shown that adolescents in treatment for alcohol dependence have reductions in the size of a brain region known as the hippocampus. Taken together, these two findings provide support for the hypothesis that early alcohol exposure perturbs and thereby alters early brain development which contributes to later vulnerabilities for alcoholism and other disorders.

What is the prevalence of alcohol problems in other phases across the lifespan? As Table I-8 shows, the prevalence of alcohol abuse and alcohol dependence within the past year varies with age. The highest previous year prevalence of alcohol dependence is found among the young adult population (defined as 18-29 years of age), particularly between the ages of 18 through 24. As has been noted, problems with alcohol use disorders are also very significant in the adolescent population, aged 12-17 years (further discussed in Chapter IV). From its peak in the young adult years, the prevalence of past year alcohol dependence declines with increasing age (adolescence, young adult, midlife defined as 30-59 years of age, and senior), falling below one percent among senior adults (defined as 60 years of age and older). According to these data, at any time point, the percentage of individuals who received treatment for their alcohol use disorder is quite small relative the numbers experiencing alcohol problems (also see Figure I-5).

Table I-8. Percentage of U.S. Adults 18 and Over with Past-year Alcohol Abuse or Dependence and Percentage of Those with Past-year Abuse or Dependence Who Received Alcohol Treatment, by Type of Treatment

Past-year disorder

Type of treatment

Age group

Abuse

Dependence

Any treatment

12-Step only

Other only

12-Step and other

All ages

4.7 (0.2)

3.8 (0.1)

7.1 (0.5)

1.1 (0.2)

2.7 (0.3)

3.4 (0.4)

Young Adult

18-29

7.0 (0.4)

9.2 (0.4)

5.9 (0.7)

1.3 (0.4)

2.3 (0.4)

2.3 (0.5)

18-24

6.7 (0.5)

11.6 (0.6)

6.4 (0.9)

1.4 (0.5)

2.8 (0.6)

2.2 (0.6)

25-29

7.3 (0.6)

5.7 (0.4)

4.9 (1.2)

1.0 (0.5)

1.2 (0.5)

2.7 (0.9)

Midlife

30-59

5.0 (0.2)

3.0 (0.2)

8.5 (0.7)

0.8 (0.2)

3.1 (0.5)

4.5 (0.6)

30-44

6.0 (0.3)

3.8 (0.2)

8.9 (1.0)

0.7 (0.2)

3.2 (0.7)

5.0 (0.8)

45-59

3.9 (0.3)

2.0 (0.2)

7.5 (1.2)

1.0 (0.4)

3.0 (0.8)

3.5 (0.8)

Senior

60+

1.4 (0.1)

0.5 (0.1)

3.4 (1.3)

1.9 (1.1)

0.8 (0.6)

0.6 (0.4)

Source: NIAAA 2001-2002 NESARC data

Figure I-3 looks at the history of alcohol abuse and alcohol dependence from a cumulative life-time perspective. The figure shows the cumulative conditional probability that an individual at a given age would have at some point in their life met the diagnostic criteria for DSM-IV alcohol abuse or dependence. As seen from the figure, by age 30 these probabilities were 10% and 17% respectively for dependence and abuse. By age 60 they are 14% and 20% respectively.

 

Figure I-3. Cumulative Probability of Onset of DSM-IV Alcohol Abuse or Alcohol Dependence by Age

Cumulative Probability of Onset of DSM-IV Alcohol Abuse or Alcohol Dependence by Age

Source: Substance Abuse and Mental Health Services Administration (SAMHSA) 2002 National Survey on Drug Use and Health (NSDUH) data (ages 12-17) and NIAAA 2001-2002 NESARC data (ages 18-60+)

Figure I-4 examines this same data from NESARC, looking at the past-year status of drinking by the interval since the individual first met the diagnostic criteria for alcohol dependence. Less than 10% of the individuals interviewed met the criteria for past-year alcohol dependence 20 years or more after initially meeting dependence criteria. Of those individuals who initially met diagnostic dependence criteria less than 5 years previously, 65% still met the criteria for dependence. As the figure shows, over 30% of individuals who initially met dependence criteria 20 or more years previously were abstinent in the past year, but in this time-frame category, as well as the other time frames since dependence onset, some individuals in the past year were in partial remission (some but not all dependence or abuse symptoms), asymptomatic risk drinkers, or low risk drinkers (less than 5 drinks on any occasion or 14 drinks per week).

 

Figure I-4. Past-year Alcohol Use Status by Interval Since Onset of Dependence

Past-year Alcohol Use Status by Interval Since Onset of Dependence
Source: NIAAA 2001-2002 NESARC data

 

Figure I-5. History of Prior Interventions in Prior to Past Year Alcohol Dependence Subjects

History of Prior Interventions in Prior to Past Year Alcohol Dependence Subjects
Source: NIAAA 2001-2002 NESARC data

 

The changes in drinking status over time shown in Figure 1-4, coupled with the finding that 24.4% of individuals who had prior to the past year (PPY) alcohol dependence recovered without the benefit of alcohol dependence treatment (Figure I-5) provides evidence that some individuals may "age-out" or experience natural recovery from the disorder.

Alcohol-Related Policy and Public Health Outcome

A wide range of public policies may affect alcohol consumption and other behaviors relating to alcohol, and therefore can have important influences on public health outcomes. In the United States, laws, regulations, and jurisprudence address (1) alcoholic beverage production, packaging, transportation, marketing, taxation, sales, and consumption, (2) financing and delivery of alcohol-related treatment and preventive services, and (3) behaviors that may be affected by alcohol, such as driving and boating. In many of these topic areas, policies are established by governments at all levels (Federal, State, county, and municipal).

Scientific research has identified a number of alcohol-related policies that have significant effects on public health outcomes. Among the policies with the best evidence of effectiveness is the minimum legal drinking age of 21, which has been shown to reduce consumption and traffic crash deaths among youth 16-21. This policy may also have other benefits, as studies have shown that deferring the initiation of drinking reduces both the risk and severity of subsequent alcohol use disorders. Although every state now sets the minimum age for possession and purchase of alcoholic beverages at 21, there is still substantial variation in states' policies toward underage drinking. Many states afford significant exceptions to the laws against possession and consumption (e.g., except for in a private residence, or only in a public place).

Policies addressing drinking and driving have been shown to reduce traffic fatalities. Every State has now established a law against driving with a blood alcohol concentration (BAC) of .08 or above. All States have also adopted so-called "zero tolerance" laws that set BAC limits for drivers under the age of 21 at no more than .02 percent. These laws, combined with a variety of other policies designed to deter driving after drinking, have helped reduce rates of alcohol-related traffic fatalities in the United States by 50% since 1982.

Alcoholic beverage taxes are another policy for which there is strong evidence of effectiveness. Although tax rates are most often established for fiscal rather than public health purposes, a number of studies have found significant relationships between higher taxes on alcoholic beverages and lower rates of traffic crash fatalities or drunk driving, particularly among younger drivers or during nighttime hours. Other research has found associations between higher alcoholic beverage taxes and lower rates of some types of violent crime, reduced incidence of physical child abuse committed by women, and lower rates of sexually transmitted diseases and liver cirrhosis mortality, as well as with increases in college graduation rates.

Public policies affecting the delivery and financing of alcohol-related treatment and preventive services may have important effects on access to treatment services. Most states now require health insurers to cover treatment for alcoholism, and a number of other states require such coverage to be offered but not necessarily included in every insurance contract. However, no Federal laws require coverage for alcoholism treatment, and Federal law exempts many large employers from state laws with such requirements. As a result, many insurance policies may not include coverage for alcoholism treatment.

Many states have laws, known as "Uniform Accident and Sickness Policy Provision Laws," or UPPL, that permit health insurers to deny payment for losses that are the result of the insured person being intoxicated. Researchers have suggested that these policies create a disincentive for health care providers in emergency and primary care settings to screen for alcohol problems, with the result that fewer individuals in need of treatment for alcohol problems are referred to treatment just when such referrals might be most effective. While studies have not yet established the true effects of UPPL provisions on treatment referrals, a few states have recently enacted laws that prohibit exclusion of insurance benefits on the basis of intoxication.

Because of the complexity of alcohol-related public policies, researchers face a challenge in identifying how specific policy measures may affect health outcomes. The Alcohol Policy Information System (APIS), developed by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), provides reliable, detailed, and comparable information on alcohol-related public policies in the United States at both the state and Federal levels. The APIS Web site ( http://alcoholpolicy.niaaa.nih.gov ) provides public access to detailed information on a wide variety of alcohol-related public policies. Intended primarily as a tool for researchers, APIS features compilations and analyses of alcohol-related statutes and regulations designed to simplify the process of ascertaining the state of the law for studies on the effects and effectiveness of alcohol-related policies.

D. Issues that Transcend the Lifespan Perspective

There are six issues that provide significant background perspectives necessary for the accurate interpretation of previous results and the formulation of research hypotheses with respect to alcohol use across the lifespan. These issues are alcohol metabolism, alcohol and gene/environment interactions, the neurobiology of alcohol, the diagnostic criteria for alcohol abuse and dependence, span. alcohol health services research, and social, legal and ethical issues of alcohol research. They are presented in this overview as they transcend the full lifespan.

D.1. Alcohol Metabolism

Individuals differ in how fast they metabolize alcohol (pharmacokinetics) and in the extent to which they are affected by a given dose of alcohol (pharmacodynamics). These individual differences affect drinking behavior, the potential for the development of alcohol dependence, and the risk for developing alcohol-induced organ damage. These individual differences in females also contribute to the extent that alcohol metabolism affects the fetus during development. Therefore, understanding these differences will provide important information about alcohol’s health effects throughout the lifespan.

The major pathway for the metabolism of alcohol is found in the liver and involves the enzyme alcohol dehydrogenase (ADH) (see Figure I-6). Alcohol is metabolized to acetaldehyde, a highly reactive and potentially toxic molecule. In most circumstances, acetaldehyde is rapidly metabolized by another enzyme, aldehyde dehydrogenase (ALDH) to acetate. Because of the rapid enzymatic conversion of acetaldehyde to acetate, the concentration of acetaldehyde in the cell is typically a thousand-fold lower than that of alcohol, and the eventual product of this pathway, acetate. Both alcohol and acetate are found at millimolar levels following drinking, while acetaldehyde is found at micromolar concentrations. [The legal intoxicating blood alcohol level in all states in the U.S. is 80 mg%, which is 17.4 mM. The normal baseline level for acetaldehyde in humans is 9 µM, or 40 µg%. After alcohol ingestion, the acetaldehyde level in most individuals will increase to 20-30 µM, or 90-- 130 µg%. Metabolism of a dose of alcohol achieving a blood alcohol concentration of 80 mg% may result in elevation of tissue acetate levels to 2mM] When the level of acetaldehyde increases, an individual may experience very dysphoric feelings and the potential for toxic reactions with various cellular components increases. Men and women differ with respect to the rate of alcohol metabolism based primarily on differences in total water body content, and potentially changes associated with the menstrual cycle. The extent of difference in alcohol metabolism between pregnant and non-pregnant women is not well studied, although it has clear implication for the amount and duration of alcohol available to the fetus during pregnancy.

 

Figure I-6. Alcohol Metabolism in the Liver

Alcohol Metabolism in the Liver

Source: Figure created by Brenda Hewitt

There are a number of variants of the ADH and ALDH enzymes, and the differences in the profile of the variants present can influence an individual's drinking behavior. The various functional variants of ADH and ALDH are shown in Table I-9.

Table I-9. Human ADH and ALDH Isozymes

Class

Nomenclature

Km (mM)

Vmax(min-1)

Alcohol

Dehydrogenase (ADH)

I

ADH1A

4.0

30

ADH1B*1

0.05

4

ADH1B*2

0.9

350

ADH1B*3

40.0

300

ADH1C*1

1.0

90

ADH1C*2

0.6

40

II

ADH4

30.0

20

III

ADH5

10

IV

ADH7

Aldehyde

?

?

a

ALDH2*1

3

 
ALDH2*2
~300--

Source: ADH: Km and Vmax values from Hurley et al., 2002; ALDH Vmax: Yin & Li (pp. 227-247), In Sun et al., Molecular Mechanisms of Alcohol: Neurobiology and Metabolism, Humana Press, 1989; ALDH Km: Mizoi et al., 1994.

Most of the alcohol consumed by humans is metabolized by the Class I and Class II ADH enzymes (Table I-9). While only one functional form of the Class II ADH isknown, the Class I ADHs exist in a number of polymorphic forms, and differences in individual Class I ADHs contribute to variation in the alcohol metabolic rate (Table I-9). Of particular importance are the three known functional variants of ADH1B. The ADH1B*2, found in the majority of Asians and 25 percent of people of Jewish ancestry, and the ADH1B*3, found in some African Americans, oxidize alcohol at a faster rate thanthe ADH1B*1 variant which predominates in most European Americans. Two functional forms of the ADH1C gene also exist (ADH1C*1 and ADH1C*2). The Class I ADH enzymes are found primarily in the liver in the cytosol compartment of the cell.

There are other enzyme pathways that can metabolize alcohol to acetaldehyde, including cytochrome P450 and catalase (Figure I-7). The cytochrome P450 isozyme CYP2E1 is the form which is predominantly involved in alcohol oxidation. It is present in an internal cellular structure known as the endoplasmic reticulum and particularly comeinto play after chronic, heavy, alcohol exposure. Alcohol metabolism by CYP2E1 also produces highly reactive oxygen species (ROS) with the potential to cause tissue damage. Unlike most Class I ADH enzymes that are primarily found in the liver, CYP2is found in a number of tissues and organs including liver, brain, heart, lung, and the neutrophils and macrophages of the immune system. Therefore, the generation of acetaldehyde and ROS within these tissues poses risks for injury to these systems. The enzyme catalase (Figure I-7), located in the intracellular structure known as the peroxisome, is also capable of oxidizing alcohol in the presence of a hydrogen per(H2O2)-generating system. However, catalase appears to be a minor pathway for alcohol metabolism.

 

Figure I-7. Minor Oxidative Pathways of Alcohol Metabolism

 

Minor Oxidative Pathways of Alcohol Metabolism

Source: Figure created by Dr. Ting-Kai Li and Dr. Samir Zakhari.

The acetaldehyde that is produced from alcohol oxidation through any of these enzyme systems is typically metabolized rapidly to acetate. ALDH catalyzes the oxidation of many aldehydes, and under conditions of ethanol exposure, ALDH enzymes specifically convert acetaldehyde to acetate. Genetic polymorphisms in the ALDH genes have been linked to decreased risk of alcoholism and increased risk of alcohol-induced cancers. A variant of the mitochondrial aldehyde dehydrogenase enzyme (ALDH2*2) is found in about 50 percent of Taiwanese, Han Chinese, and Japanese populations. The enzyme expressed by ALDH2*2 is virtually inactive. Consequently, individuals with one, and particularly two copies of this allele show elevations in acetaldehyde after consuming alcohol (see Figure I-8). Individuals with both ADH1B*2 and ALDH2*2 genes have been shown to have virtually complete protection against developing alcoholism, presumably due to the adverse effects of elevated acetaldehyde. This allelic combination is curiously absent in Native American Indian populations, who have a high prevalence of alcoholism, suggesting that other combinations of ADH and ALDH genes may confer various forms of protection or susceptibility to alcohol use disorders.

Figure I-8. Blood Acetaldehyde Concentrations of Han Chinese Men with Different ALDH2 Allelotypes (0.2 g/kg ethanol)

Blood Acetaldehyde Concentrations of Han Chinese Men with Different ALDH2 Allelotypes (0.2 g/kg ethanol)

Source: Chen et al. Interaction between the functional polymorphisms of the alcohol-metabolism genes in protection against alcoholism. Am J Hum Genet 65:795-807, 1999

Most of the acetate arising from ethanol metabolism departs the liver via the circulatory system and is eventually metabolized to carbon dioxide (CO2) and water by way of the tricarboxylic acid cycle (TCA) in heart, skeletal muscle, brain, and liver. Further, acetate itself is not an inert product; in addition to being a metabolic source of energy, it can increase portal blood flow in the liver, and potentially in other organs, and contributes to the biosynthesis of adenosine which has its own effects on cortical and coronary blood flow in response to need.

The oxidation of alcohol through ADH, and acetaldehyde through ALDH, is accompanied by the conversion of the co-enzyme nicotinamide-adenine dinucleotide (NAD+) to its reduced form NADH (Figure I-7). When sufficiently large amounts of alcohol are consumed, alcohol metabolism can change the reductive-oxidative state of the cell (redox state), expressed as the ratio of NAD+/NADH. The change in the NAD+/NADH ratio, in turn, can affect a number of metabolic pathways within the cell. Further, the NADH generated through alcohol and acetaldehyde oxidation is subsequently re-oxidized to NAD+ through the mitochondrial electron transport chain, a process that involves the generation of the energy intermediate ATP. Enzymes within the electron transport chain also have the potential to generate ROS. In a cellular environment low on antioxidant defense mechanisms (e.g., glutathione), such as occurs after heavy alcohol exposure, these ROS have the potential to disrupt developmental processes and to cause tissue damage.

In addition to the oxidative pathways of alcohol presented above, alcohol can also be non-oxidatively metabolized by at least two pathways. One leads to the formation of fatty acid ethyl esters (FAEE) and the other to phosphatidyl-ethanol. Both oxidative and non-oxidative pathways of alcohol metabolism are inter-related, and may result in tissue injury throughout the lifespan.

Opportunities for Research in Alcohol Metabolism Across the Lifespan

D.2. Alcohol and Gene/Environment Interaction, Epigenetics
Neither genes nor environment alone can explain why any particular individual develops alcohol dependence. Rather, as a complex disorder, risk for the development of alcohol dependence will be a consequence of the interplay of multiple genes, potentially multiple environmental factors, and the interaction of these genes and the environmental factors. Similarly, it is not likely that any single mechanism of gene-environmental interaction will explain all vulnerability to alcohol dependence. While in the past decade investigators have sought to define both genes and environmental factors underlying risk, this effort had been limited due to a lack of powerful technologies and methodologies that could be applied to the genetic study of complex disorders such as alcoholism. In recent years, advanced technologies such as single nucleotide polymorphisms (SNPs) and haplotype maps have enabled scientists to identify genes associated with these disorders. Although a few genes, such as GABRA2, ADH, ALDH, CHRM2, OPRM1 and NPY, have been linked to alcohol dependence and its related disorders, it is apparent that more genes will be rapidly identified. A number of candidate genes in animals and humans are presented in Table I-10.

 

Table I-10. Genes Contributing to Alcohol-Related Behaviors in both Rodents and Humans

Table I-10. Genes Contributing to Alcohol-Related Behaviors in both Rodents and Humans

 

The search for both genetic and environmental risk factors includes both human population genetics investigation, as well as studies involving animal models. Specifically, selected animal strains are used to model the endo- and intermediate phenotypes (see Table I-11) involved in the development of human alcohol dependence. While animal models of alcohol tolerance and alcohol preference have been developed in the past, refinement of current models is still required in order for them to more closely parallel those features of the clinical syndrome phenotype, including modeling such contributing traits as anxiety, propensity for relapse, and obsessive-compulsive behaviors such as craving.

Table I-11. Definition of Endophenotype, Intermediate Phenotype, and Clinical Syndrome Phenotype

Endophenotype: innate or biological host factors that may predispose an organism to alcohol dependence (e.g., temperament, gene expression, electrophysiology, developmental biology)

Intermediate phenotype: host factors interact with environmental factors to facilitate the development of alcohol dependence (e.g., sensitivity, tolerance, reward)

Clinical Syndrome Phenotype: the transition from voluntary to nonvoluntary, obsession with and compulsion to use alcohol

 

Epigenetics

One additional route by which alcohol may affect the development of alcohol disorders, from alcohol dependence to organ disease is through epigenetics, which refers to stable alterations in the genome, sometimes heritable through cell division, that do not involve permanent changes to the DNA sequence itself. Epigenetic processes act as an additional source of biologic variation beyond that attributable to the genetic code. These processes involve the chemical modification of the constituents of the chromosome, the DNA molecules and the gene-regulating proteins known as histones, and may occur as a consequence of exposures to specific environmental substances and stimuli. Alcohol and its metabolites could be important environmental factors contributing to epigenetic processes. For example, alcohol has been shown to cause acetylation at specific histone sites in the rat chromosome, resulting in increased expression of the ADH gene. Further, alcohol has the ability to alter the normal biochemical pathways by which DNA and histones might be modified in response to other events occurring in the environment. For example, alcohol can interfere in the metabolic pathways leading to the biosynthesis of the intermediates required to modify DNA, by altering biosynthetic pathways involving folate, and inhibiting the synthesis of a “methyl donor” known as S-adenosyl methionine (see Figure VI-1 in Chapter VI).

Related to such metabolic alterations, alcohol may influence epigenetic processes in ways opposite to that necessary for normal functioning, and in the case of the fetus, to that required for normal development. Epigenetic events also may contribute to the development of alcohol tolerance and sensitization, obsessive-compulsive drinking, craving, cognitive effects of chronic drinking and organ damage associated with heavy drinking.

Cellular Phenotypes/Immortalized Cell Lines

Recent advances in rapid molecular biology techniques coupled with the sequencing of the human genome, and the genomes from select animal model systems, has provided the opportunity to identify the complex relationships that inter-connect genotype and phenotype underlying the progression 'from sequence to function.' A thorough understanding of biological systems requires a complete assessment of not only gene-gene interactions, but protein-protein interactions, post-translational modifications, and metabolic effects. One approach to understanding these complex interactions involves the phenotypic characterization of immortalized cell lines (of known genetic background) from organ systems of interest following the application of a manipulation, such as alcohol exposure under conditions within the physiological range of normal and binge human alcohol consumption. Gene targeting experiments can further elucidate the molecular signals in temporal sequence by perturbation of the cell line through knockdown/inactivation or over-expression of genes in isolation combined with microarray techniques that allow expression of phenotypic changes in the response to alcohol exposure.

Opportunities for Exploring Alcohol and Gene/Environment Interaction, and Epigenetics Across the Lifespan
There are many opportunities to explore the effects of alcohol exposure on the interaction of genes and environment across the lifespan, even though the effects of heavy alcohol consumption may differ significantly given the age of exposure, and with respect to alcohol's direct or indirect effects.
D.3. Neurobiology of Alcohol

Since the brain is a significant target for alcohol-induced toxic effects, and the brain undergoes development and maturation continuously from conception to birth and into adulthood, the effects of alcohol on neurobiology and neural processes in general are observed throughout life. Therefore, at any point in the lifespan, alcohol consumption may affect the normal physiology of the CNS, which makes the topic of alcohol's detrimental effects on the brains of any age of importance for comprehensive examination.

Alcohol has complex pharmacodynamic effects on the body, primarily through its interactions with the brain within the central nervous system (CNS). Alcohol's pharmacologic effects typically begin with mild stimulation, followed by CNS depression as shown in Figure I-9. Disinhibition and anxiolysis may also be experienced in the early phase following alcohol ingestion. As is noted in Figure I-9, as breath alcohol concentration (BrAC) increases, the likelihood and severity of functional impairments increases, ranging from impaired motor function to respiratory depression and death.

 

Figure I-9 Pharmacodynamics of Ethanol on the Central Nervous System

 

Pharmacodynamics of Ethanol on the Central Nervous System

Among the physiological or behavioral consequences of chronic alcohol use, that is, drinking too much, too fast and/or too often, are the disorders of alcohol abuse, and alcohol dependence. However, there are other pathologic consequences to both the CNS and the peripheral nervous system (PNS) that can arise from drinking over long periods of time. These usually do not clinically manifest themselves until the midlife period. Alcohol neurotoxicity can result from heavy alcohol consumption beginning as early as adolescence, which may be critical to understanding why certain individuals drink excessively and what biological factors continue to prompt them to drink. Furthermore, alcohol neurotoxicity affects the fetus with long-term consequences. Therefore, a discussion of alcohol's effect on the brain involves all ages of individuals.

Alcohol's effect on the brain can have immediate, direct, and wide-ranging ramifications, from effects on normal physiology (patterns of sleep-wake, thermoregulation), to effects on basic motor functions (balance, gait, coordination), to effects on thoughts and emotions (cognition). Of particular interest are physical or chemical alterations in the brain that may cause changes in cognition leading to a variety of responses that manifest as, for example, the decision to start or stop drinking alcohol or the decision to seek help for an AUD. The adaptations that occur in the development of alcohol dependence occur within the CNS as well. Therefore, it is important to explore the effects of alcohol on the brain at many levels, from cellular and molecular biology to cognitive effects, using the range of techniques and methods of neuroscience. Some relevant research topics that may advance the knowledge about the effects of alcohol on brain include an examination of synaptic protein adaptation, the differential temporal vulnerability (differences across the lifespan) of various brain regions and neuronal cell types to long-term consequences of alcohol-induced toxicity, changes in frontal lobe function associated with alcohol-induced cognitive alterations, impairments of neuroimmune and neuroendocrine function that predispose individuals to organ damage, and neuronal plasticity. These areas can be approached from a variety of perspectives in both clinical (human) and experimental (animal models) settings using imaging and functional imaging, electroencephalography, and cellular and molecular biology techniques.

Recommendations of the NIAAA Extramural Advisory Board (EAB) "Mechanisms of Alcohol Addiction ( MAAIT II)"
  • Learning and tolerance mechanisms. Explore learning, cognitive and tolerance mechanisms that facilitate or inhibit the escalation of drinking (within and across drinking bouts) in human and animal paradigms, and identify actions in relevant molecular and neural systems supporting these mechanisms.
  • Endophenotypes (risk and genetics). Identify physiological, temperamental, and cognitive traits and responses to alcohol associated with risk for or protection from developing alcohol dependence and study mechanistically-based hypotheses in animal and human laboratory paradigms.
  • Adolescent to adult transitions. Study alcohol's actions upon and interactions with genetic, physiological, hormonal, temperamental, neurocognitive, and social-affective factors associated with transitions into adolescence and adulthood that establish drinking patterns leading to uncontrolled drinking and examine the role of gender and early life events on this trajectory.
  • Epigenetics. Determine the mechanisms and examine the role of epigenetic modifications in the etiology or progression of alcoholism and alcohol-relevant behaviors, examining the influence of alcohol exposure at various life-stages and interactions with stressors and other internal and external moderators.

More detail on the recommendations made by the NIAAA EAB can be found at: http://www.niaaa.nih.gov/ResearchInformation/ExtramuralResearch/AdvisoryCouncil/

 

Opportunities for Examination of the Neurobiology of Alcohol Across the Lifespan

The central nervous system is a major target for adaptive, as well as toxic effects of alcohol across the lifespan, e.g., alterations in developing neurons, changes in neurotransmitter systems that alter neuronal function. Therefore, there is a wealth of information to be gained from researching the basics of the neurobiology of alcohol across various ages of subjects and experimental systems.

Since the early 1900s, numerous definitions of AUDs have been proposed. Currently, in the United States, the clinical standard used for defining and diagnosing AUDs is the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV).

Definitions of alcohol abuse (see Table I-1) and dependence (see Table I-2) appearing in the DSM-IV both describe maladaptive patterns of alcohol use leading to clinically significant impairment or distress.

DSM-IV alcohol abuse requires at least one of the following four symptoms to occur within a 12-month period:
DSM-IV alcohol dependence requires that at least three of the following seven criteria be met in a 12-month period:

Several issues have been raised concerning the applicability of the DSM-IV diagnostic definitions. With regard to dependence, the categorical nature of the diagnosis has been criticized as failing to represent the degree of severity inherent in the phenomenon. Each diagnostic symptom criterion carries equal weight in the classification, when clearly some criteria subsume symptoms that are more severe or disabling than others. The DSM-IV dependence diagnosis has also been questioned due to the absence of alcohol consumption measures, especially those consumption measures related to excessive drinking that have been found to increase individuals' risks for a variety of physical and psychiatric disorders. To address these issues, research has begun to focus on developing quantitative representations of AUD diagnostic criteria using statistical methods that provide differential severity weighting for individual AUD symptoms and allow for the inclusion of alcohol consumption variables (Saha et al., 2007).

Figure I-10. Severity of Alcohol Use Disorder: Comparison of Frequency of Risk Drinking (5+/4+) with Average Daily Ethanol Intake

 

Severity of Alcohol Use Disorder: Comparison of Frequency of Risk Drinking (5+/4+) with Average Daily Ethanol Intake

Source: Dawson, D. Laboratory of Epidemiology and Biometry, NIAAA, 2007.

 

As part of this effort, the relationship of average daily volume of alcohol consumption to severity of AUD, as well as the relationship between risk drinking and AUD was analyzed from the NESARC data. As seen in Figure 1-10, the increase in severity of AUD is non-linear with respect to average daily alcohol consumption or the frequency of risk or binge drinking, but rather increases at a greater than linear. One interesting observation is that the severity of AUD attained is about the same for individuals who engage in risk drinking once a month (5 drinks per occasion for males/4 drinks per occasion for females) as it is for individuals whose overall average daily alcohol consumption is 1 standard drink per day (30 drinks per month) (the blue bars in the two graphs in Figure 1-10).

Another important issue related to the current DSM-IV formulation of alcohol abuse and dependence concerns the relevance of some of the criterion items to certain subgroups of the population. For example, some researchers have questioned the applicability of DSM-IV symptom items to females, a result of the historical definitions of diagnostic criteria based on clinical samples that have been composed largely of middle-aged males. The need to determine if differential case identification for AUDs exists for males versus females will be paramount for future prevention and intervention efforts. Biases attributable to language, differences in response tendencies (e.g., trait desirability, social approval, or acquiescence), or cultural expectations and experiences can also lead to differential reliability and validity of the AUD diagnoses across race-ethnic subgroups of the U.S. population.

Further, questions have been raised about the applicability of specific diagnostic symptom items across the lifespan, particularly among youth, young adults, and the elderly. Whether some symptoms of AUDs may be more relevant to different stages of the life course is an important research question. Given the relationship between early-onset drinking and the increased risk of developing an AUD, identifying criterion symptom items specific to youth and young adults will be critical to prevention and intervention efforts. Similarly, identifying AUD symptoms of greatest relevance in the elderly can increase our ability to recognize serious alcohol problems among this important subgroup of the population, which is projected to increase dramatically over the next 10 years.

Opportunities Related to the Diagnostic Criteria for Alcohol Abuse and Dependence

D.5. Alcohol Health Services Research Across the Lifespan

Alcohol health services research is a multidisciplinary field of applied research that seeks to improve the effectiveness, efficiency and equity of services designed to reduce the public health burden of alcohol use disorders across the lifespan. It does this by examining how social factors, financing systems, service environments, organizational structures and processes, health technologies, and personal beliefs and behaviors affect access to and utilization of healthcare, the quality and cost of healthcare, and in the end our health and well-being. Ultimately the goal of alcohol health services research is to identify ways to organize, manage, finance, and deliver high-quality care consistent with developmental needs of patients and their families.

Opportunities Related to Alcohol Health Research Services Across the Lifespan
D.5. Ethical, Legal and Social Issues in Alcohol Research

The consumption of alcohol, more than any other substance, is governed by a variety of complex social and legal conditions. The complexity around alcohol consumption by humans adds important ethical, social, and legal issues (ELSI) to alcohol research. Each researcher using human or animal subjects must ensure that the research is being conducted in an ethical manner. NIAAA recognizes that adequate consideration of ethical, legal and social issues in alcohol research requires that the home institution provide support and guidance for the researchers as they carry out their research programs. NIAAA continues to approach this challenge though such activities as:

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CHAPTER II. The Embryo and Fetus

A. Background

The earliest stages of life, in particular, embryonic and fetal development, are periods of great vulnerability to the adverse effects of alcohol. A known teratogen (an agent capable of causing physical birth defects), alcohol may also damage neurological and behavioral development even in the absence of obvious physical birth defects. Alcohol's teratogenic effects were recognized over three decades ago, and it is now the leading known environmental teratogen.

Ranging from mild to severe, alcohol-induced birth defects are known as fetal alcohol spectrum disorders (FASD). The severity of defects depends on the dose, pattern, and timing of in utero exposure to alcohol. Research in animal models has demonstrated that the potential for adverse effects increases with the maternal blood alcohol concentration (BAC). As such, the peak dose, as measured by BAC, is a more important determinant of harm than is the total dose consumed.

The most serious adverse consequence of prenatal alcohol exposure is fetal alcohol syndrome (FAS), a devastating developmental disorder characterized by craniofacial abnormalities, growth retardation, and nervous system impairments that may include mental retardation. Children and adults with FAS have irreversible neurobiological deficits that affect multiple systems, ranging from motor control to executive function. Consequently, many secondary disabilities may occur, such as learning disabilities, attention disorders, failure in school, poor social skills, delinquent or criminal behavior, psychiatric co-morbidities, and premature and/or promiscuous sexual activity. Prenatal alcohol exposure itself may be a risk factor for subsequent alcohol and other drug use disorders later in life. The disabilities of FAS are life-long and place heavy emotional and financial burdens on individuals, families, and society.

Another fetal alcohol spectrum disorder is partial FAS, which includes the facial and neurodevelopmental deficits of FAS but not the growth deficits. Other FASD outcomes include alcohol-related birth defects (ARBD), where physical attributes of FAS are seen in the absence of the full syndrome, and alcohol-related neurodevelopmental disorder (ARND) in which neurobehavioral deficits are consistent with FAS, but the facial or physical features of FAS are absent.

By virtue of the lifelong learning and neurobehavioral deficits that characterize FAS and other types of FASD, many consider the central nervous system to be most critically affected by prenatal alcohol exposure. Imaging and neurobehavioral research in individuals with FAS and FASD reveals that some brain regions appear to be most sensitive to prenatal alcohol while other areas apparently are spared adverse effects. Particularly vulnerable regions include the frontal cortex, hippocampus, corpus callosum, and components of the cerebellum, including the anterior cerebellar vermis. Obviously, the extent of damage to any brain area may be related to the timing of alcohol exposure relative to the rapid development or neurogenesis of a particular brain region, and the stage of embryonic development.

Epidemiological studies have revealed other adverse outcomes of prenatal alcohol exposure, including an increase in the risk for spontaneous abortion, pre-term delivery, stillbirth, and sudden infant death syndrome (SIDS).

B. Epidemiology

Despite alcohol's potent teratogenicity, only a small proportion of women who drink heavily give birth to children with FAS. The prevalence of FAS and FASD are presented in Table II-1 for selected countries. In the U.S., the prevalence of FAS has been estimated at 0.5-2.0 cases per 1000 births, with FASD projected to occur at several times that prevalence (10 per 1000 births). In some parts of the world the rate of FAS is far greater than in the U.S. This is particularly true in countries where alcohol consumption during pregnancy is more common than in the U.S. For example, in parts of South Africa, where farm wages once were paid in part, with alcohol, a heavy drinking culture is quite prevalent among the mixed ancestry farm workers. The incidence of FAS in this region exceeds 60 cases per 1000 individuals.

Table II-1. Prevalence of FASD, FAS and Associated Disorders (FAE, ARND, ARBD) by Country (per 1000 cases)
Country
Fetal Alcohol Spectrum Disorders
Fetal Alcohol Syndrome
Canada
25 -- 46^
10.3^
France
6.0 (FAS and ARBD)
1.2 -- 2.9
Italy
20 -40
3.7 - 7.04
South Africa
-----
65-74*
Sweden
3.3 (FAS and ARBD)
1.7
United States
10
0.5 -- 2.0
Source: Canada: Habbick et al., 1996, Williams et al., 1999, Boland et al., 1998; South Africa: Viljoen et al., 2005; Italy: May et al., 2006; Sweden, France, and the United States: IOM Report, 1996.
Fetal Alcohol Spectrum Disorders include FAS, ARND, ARBD and FAE.
*Western Cape Province, Republic of South Africa
^ Among Aboriginal populations in Northern British Columbia and Yukon territory
Given that alcohol consumption is the prime factor responsible for FASD, the extent of drinking in pregnancy is an important epidemiological question. Despite a number of prevention efforts, including point of sale warning signs and bottle labeling, surveillance data indicate that 10% of pregnant women drink some alcohol and 2% are binge drinking. More than 12% of women who are not using contraception and are at risk of becoming pregnant are drinking at levels that exceed 7 drinks per week or 4 or more drinks per occasion.

 

C. Etiology

Research has shown that, in the development of FASD, alcohol's causative effect can be influenced by a number of maternal factors, including hormone status (e.g., thyroid hormones), nutrition, age, parity, and drinking history.

Research shows that genetic factors influence adverse pregnancy outcome in both humans and animal models. Animal research has also shown that the genetic profiles of the mother and the fetus are important for determining the potential for risk of physical birth defects, prenatal mortality, learning and other neurobehavioral deficits in the offspring. In humans, the presence of a specific variant of the alcohol dehydrogenase gene, ADH1B*2, in either the mother or child, has been shown to decrease risk for FAS. Other studies have shown that the presence of the ADH1B*3 variant decreases risk for neurodevelopmental deficits associated with ARBD. Both of these ADH variants have kinetic properties that make them more efficient at oxidizing alcohol to acetaldehyde, a noxious intermediate metabolite, suggesting that elevated acetaldehyde levels may contribute to decreased alcohol consumption to lessen the risk FAS and FASD.

Recommendations of the NIAAA Extramural Advisory Board (EAB) "Fetal Alcohol Spectrum Disorders Research"
  • To define full range of FASD/prenatal alcohol phenotypes and endophenotypes across the lifespan using advanced methods, technologies and applications -- integrative biology/systems biology and database approaches.
  • Develop and validate biomarkers to assess the exposure and insult to the mother and the fetus.
  • Conduct analyses of pre- and postnatal nutritional, genetic, epigenetic and environmental factors to determine risk or protective factors and co-morbidities (e.g., diabetes, tobacco and other drugs) that may alter susceptibility and natural history of fetal alcohol spectrum disorders.
  • Study the safety and efficacy of interventions (e.g., nutritional, pharmacological, neurobehavioral, and environmental) during periconceptional, pregnancy, and lactational periods.
  • Elucidate biological mechanisms that contribute to ethanol teratogenesis in a range of experimental models and in humans, including mechanistic links to biomarkers and treatment.

Detailed information regarding these EAB recommendations can be found at: http://www.niaaa.nih.gov/ResearchInformation/ExtramuralResearch/AdvisoryCouncil/

 

With respect to environmental risk factors, parents' socio-economic status (SES) has been shown to be inversely associated with adverse prenatal outcomes. However, the mechanisms accounting for this finding remain to be established and the possibility exists that some factor associated with SES such as drinking pattern, paternal drinking, or nutrition may account for the observation.

Embryonic and fetal development are characterized by rapid, but well-synchronized patterns of gene expression, including epigenetic imprinting, which makes the embryo/fetus particularly vulnerable to harm from alcohol. Hence, this stage of life provides fertile ground for the gamut of teratogenic consequences. As noted in this Plan's Overview, alcohol has the ability to affect epigenetic pathways directly by disruption of metabolic events in the biosynthesis of metabolites involved in epigenetic modification (for example, the methyl donor S-adenosyl methionine) resulting in altered gene expression and consequent developmental injury. In addition, alcohol-induced errors in gene imprinting at the level of the gamete may be heritable across multiple generations. Therefore, the effect of alcohol on embryonic/fetal development is similar to shooting a moving target whereby development is differentially vulnerable at different stages of development following different durations and patterns of alcohol exposure.

Although there is both clinical and experimental evidence that maternal history of drinking in the absence of direct alcohol exposure to the embryo does result in intrauterine growth retardation (one characteristic of FAS/D), much of the research to date has focused on the effects of alcohol on the embryo per se, since a diagnosis of FAS cannot occur in the absence of direct fetal alcohol exposure (maternal alcohol consumption during pregnancy). Evidence for alcohol-induced alterations has been found as early as the embryonic stage of development. Research with a frog model of FASD has demonstrated that alcohol can induce developmental injury at alcohol concentrations that are attainable in heavy or binge drinking. Embryonic alcohol exposure decreased the expression of several key neural genes necessary for development (Pax6, Otx,6, Sox 3 and NCAM, TBX5, VAX2 among others). The effect of these alterations in gene expression produced outcomes consistent with the types of deficits seen in FAS including microcephaly and micro-ophthalmia as well as other ocular abnormalities, overall growth retardation, as well as delayed gut development. This research further demonstrated that reactive oxygen species (ROS) and potentially reactive nitrogen species (RNS) were involved in the mechanisms by which alcohol caused these developmental effects. The anti-oxidant ascorbic acid (vitamin C) was capable of protecting against microcephaly and overall growth impairment.

Further evidence for detrimental effects of alcohol exposure on early development has been demonstrated in research using the zebrafish embryo model system. Zebrafish embryos exposed to alcohol of various concentrations show alcohol-induced facial dysmorphologies (especially deficits involving the eye), defects in brain, somatic growth, limb, and cardiac development, abnormalities in gene expression, and behavioral abnormalities (learning and memory, startle reflex) in adult fish exposed during embryogenesis. Of interest, the behavioral abnormalities occur at concentrations lower than those that caused cell death. Furthermore, the timing of the embryonic alcohol exposure appears to be related to differential adverse developmental outcome.

Other research studies have implicated ROS in the mechanisms by which teratogenicity develops following prenatal alcohol exposure, including programmed cell death. Programmed cell death, or apoptosis, is an essential process for normal development. Specific cells required only at a particular stage of development undergo apoptosis once their developmental function is completed. An apoptotic event occurring either too early, or too late, can alter the developmental process. Both in vivo and in vitro studies have demonstrated that alcohol can alter cellular responses to regulatory mediators of apoptosis in susceptible cell populations. Alcohol induction of oxidative stress may cause apoptosis, in part by reducing intracellular antioxidant capacity. This increase in ROS enhances the permeability of the mitochondrial membrane which, in turn, leads to induction of an apoptotic signaling cascade involving the enzyme caspase. These findings led investigators to test whether antioxidant agents could prevent fetal alcohol injury. Results of such studies to date have been mixed, with decreased cell death in animal and tissue culture models but no change in neurobehavioral deficits observed in the offspring.

One area where prenatal alcohol exposure may bring about a life-long consequence involves the fetal programming of the hypothalamic-pituitary-adrenal axis (HPA) axis and its response to stress. Research in animal models has shown that alcohol exposure during fetal development can reprogram the HPA axis such that HPA tone is increased throughout life. The consequent sustained elevations of stress hormones can produce adverse effects on behavioral, cognitive, emotional, physiological and metabolic functions. Changes in immunological function can increase vulnerability to illnesses throughout life. While this particular research demonstrates an effect of prenatal alcohol on fetal programming of adult HPA responding, other research has demonstrated that postnatal maternal behaviors can permanently alter offspring through imprinting or epigenetics. In this particular study, maternal-infant interactions resulted in permanent variations in specific gene expression directly through an imprinting process. Therefore, a potential mechanism exists for epigenetic or fetal programming in the offspring of mothers exposed to alcohol during pregnancy.

Another area where prenatal alcohol exposure may cause life course problems involves disturbances of circadian rhythm. Prenatal alcohol exposure has been shown to alter the circadian rhythm of biological processes, which may contribute to long term effects on health, including sleep disturbances and psychiatric disorders.

Components of many neurotransmitter systems appear to be involved in prenatal alcohol-induced fetal injury. For example, several studies implicate the NMDA glutamate receptor system in alcohol teratogenesis. Prenatal alcohol exposure on gestational day 8 of the mouse caused an eventual change in the expression pattern of NMDA receptors, with a decrease in the NR2B receptor and an increase in the NR2A receptor. Researchers have hypothesized that this change could contribute to learning deficits in FASD as NR2A is less modifiable than NR2B. Also, the alcohol withdrawal-induced excitotoxicity of the NMDA glutamate system that follows heavy exposure to alcohol has been proposed as another mechanism by which injury to the fetal hippocampus may occur. Research has shown that the NMDA receptor blocker, MK-801, could attenuate the reductions in fetal hippocampal cell numbers in the rat associated with alcohol withdrawal. Similarly, the selective NMDA antagonist, eliprodil, was shown to reduce the severity of learning deficits in rats observed after exposure and withdrawal from alcohol, with alcohol administered on postnatal day 6 (corresponding to mid-third trimester in the human) and eliprodil administered the following day. Both of these findings indicate that glutamate/NMDA excitotoxicity can contribute to alcohol-induced fetal brain injury.

Prenatal alcohol exposure has been shown to affect the serotonergic system of the rodent, by reducing the quantity of serotonin acting as a growth factor during organogenesis and neurogenesis, and by depleting the amount of serotonin available for use as a neurotransmitter in older offspring, resulting in aberrant neural tube development and depletions in the density of serotonergic neurons, respectively Alcohol exposure in the prenatal period has also been demonstrated to affect other neurotransmitter systems including the muscarinic acetylcholine system, catecholaminergic (DA, NE), and GABA-ergic systems through various mechanisms that alter the availability of the neurotransmitter (e.g., depletion of neurotransmitter producing neurons, changes in baseline or stimulated release or uptake of neurotransmitters, or changes in the sensitivity of the neurotransmitter receptors).

Another important functional system altered by prenatal alcohol is the L1 cell adhesion system. Alcohol potently inhibits the cell adhesion and axonal growth properties of L1. Of particular interest is that children who are born with mutations involving the L1 molecule develop birth defects with a phenotype that is similar to FAS.

One striking observation is that short peptide fragments from two of the brain's neuropeptides, activity-dependent neurotrophic factor (ADNF) and activity-dependent neurotrophic protein (ADNP) have been found to afford significant protection from fetal alcohol injury at concentrations as low as the femtomolar (10-15) range. Peptide fragments from ADNF and ADNP could prevent alcohol-induced alterations in the function of L1. These peptide fragments have also been found to protect against reactive oxygen injury in the developing fetus.
D. Prevention

Researchers have pursued two paths for preventing FASD. The most desirable route for prevention involves eliminating or significantly reducing alcohol consumption by women during pregnancy. Other efforts have explored the possibility of minimizing the damage caused by prenatal alcohol exposure.

The Institute of Medicine addressed the issue of prevention of FASD in the mid-1990s and proposed three approaches that differed in degree of intensity depending on the level of risk of the pregnant woman.

The broadest approach involves universal prevention measures targeted to the global community of men and women, and conveys general education on risks and information to abstain from alcohol in pregnancy. Examples include notices in bars, restaurants and other points of sale, broad media campaigns, and labels on alcohol beverage containers. While these efforts raise the level of overall awareness, research to date has not demonstrated that universal approaches decrease alcohol use among the group at highest risk for having an FASD child. The next level involves selected prevention efforts which are directed to those women who are in special risk groups, for example, a population that is known to have a greater percentage of women who drink during pregnancy, or who frequently engage in binge drinking. An example may be a screening effort in primary care or prenatal clinics in a community known to have a high prevalence of risk drinking. Indicated prevention is at the highest level of intensity and is directed at individuals known to be more vulnerable because of a high prevalence of drinking in a high risk manner, including frequent binge drinking, having a diagnosis of alcoholism, or having previously given birth to a child with an FASD. To date, the limited research on selected and indicated prevention efforts has shown that these methods can produce changes in drinking behavior that would be expected to decrease risk for an adverse fetal outcome. Indeed, research has shown that both screening for alcohol use and administration of brief interventions in the clinic (selected prevention) have positive effects on drinking reduction during pregnancy. Also, conducting a single postpartum follow-up session showed promise for maintaining the gains made possible by the intervention during pregnancy. Several screening instruments have been demonstrated to have good sensitivity and specificity in identifying women at risk, and their effectiveness may be enhanced by computerized self-interview.

Pharmacological intervention during pregnancy is an alternative approach to prevention that may have applicability when there is early alcohol exposure before a woman recognizes that she is pregnant, or otherwise fails to stop drinking in pregnancy. Unlike many other teratogens that have a limited period of exposure vulnerability, there are many periods during gestation when alcohol can produce embryonic and fetal injury. While some agents have shown intriguing results with respect to the prevention of FASD associated injury, to date no agents have progressed to the point of consideration for human trials. Therefore, this area would best be described as at an early stage of development. However, among the promising potential agents tested in animal models are anti-oxidants that have been shown to reduce fetal cell toxicity, anti-inflammatory agents such as prostaglandin inhibitors; the nutritional co-factor choline; and agents that interfere with alcohol’s action in disruption of the functioning of the L1 cell adhesion receptor. Also, two neuropeptides derived from the neurotrophic factors ADNF and ADNP have been shown to exert significant protection from alcohol-induced fetal injury in cell culture and animal models, and derivatives of these factors may offer significant potential as future preventive agents.

 

E. Treatment

Diagnosis: Important to the implementation of treatment is the identification of the infant or child with FAS or FASD. Diagnosis of FAS and FASD often has been difficult due to the lack of a biological marker, nonspecific and often subtle symptomatology, differences in the severity and timing of the insult, individual differences in response and resiliency, and the overall complexity and plasticity of brain development. Diagnosis in neonates and infants is further complicated because neurodevelopmental deficits important to case identification may not be discernable in infancy, and facial features may not be prominent in the neonate. Because the physical signs of FAS moderate with age, and behavioral manifestations of FASD change according to developmental stage, diagnosis during later childhood (puberty and beyond) is even more difficult than at younger ages. However, with more recent advances in the application of complex, detailed facial imaging, researchers have been using the facial dysmorphology associated with FAS as a biomarker for CNS damage following confirmed maternal gestational alcohol consumption. So, while a definitive biomarker is still lacking, the use of an objective measure, facial imaging, may confirm the use of facial dysmorphology as a biomarker for gestational alcohol exposure.

Analysis of magnetic resonance images (MRI) of the brains of adolescents and adults with FAS, FASD, and normal subjects reveals that the shape of the corpus callosum is much more variable in the brains of alcohol-affected subjects. Statistical analysis of this excess variability reveals that it can discriminate affected individuals with good sensitivity and specificity. Further, the altered shape of the corpus callosum serves as a permanent record of brain damage, even in subjects suspected of FAS or FASD relatively late in life, or who lack the physical signs of FAS. More recently, a pilot study has provided evidence for the use of ultrasound in infants, through the infant's fontanelle, in determining the shape of the corpus callosum. This approach may offer the potential to assess the corpus callosum in infants as a diagnostic indicator for FAS. Early case recognition is important in the quest for early initiative of therapy.

Therapeutics for FASD behavioral deficits: Several promising approaches to restoration or improvement of neurobehavioral deficits are being explored in animal models. Twenty days of complex motor skill training in adult rats was shown to restore performance deficits on a motor task that resulted from binge exposure to alcohol in the neonatal period. Recent results showed that this training stimulates synaptogenesis in the cerebellum. Thus, Purkinje cells that survive the initial alcohol insult are capable of experience-induced plasticity. Other forms of directed activity may have similar beneficial effects in other neuronal cell populations.

Prenatal alcohol exposure produces functional changes in the cholinergic system of the hippocampus, leading to hyperactivity, passive avoidance deficits, and impairments in spatial and working memory. Dietary supplementation with choline, a precursor of the neurotransmitter acetylcholine, was shown to decrease hyperactivity and improve spatial and working memory in young rats that had been exposed to alcohol prenatally. The choline treatment had no effect on alcohol-induced deficits in motor balance and coordination, which are controlled by the cerebellum rather than the hippocampus. Thus, choline's ameliorative effects may be selective for hippocampal dysfunction.

Of particular importance are educational and skill oriented interventions to address the learning and neurobehavioral deficits of FASD children. Pilot studies with these populations are showing improvements in performance that can enhance the life skills of individuals with FAS and other FASD.

F. Opportunities

G. Outreach

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CHAPTER III. Birth to Age Ten

 

A. Background

The period from birth to age 10 is perhaps the most remarkable of all developmental periods with respect to the sheer extent of the changes that take place. It encompasses infancy, the toddler and preschool years, and middle childhood. By age 10, many of the most basic human systems for adapting to the world have developed and have some stability. These include the ways in which the individual will perceive and learn, problem solve, communicate, regulate emotion and behavior, respond to stress, and relate to other people.

As children traverse the period from birth to age 10 there are a number of key transitions that they must negotiate and developmental milestones they must achieve. These include: attachment to caregivers and others; understanding the language of the family; preschool entry and the transition to elementary school; understanding, speaking, reading and writing the language of the culture/school; sitting, walking, skipping and other developmental motor milestones; compliance with rules for conduct and impulse control; toilet training; playing with peers; and acceptance among peers in key community or school contexts.

A child's development takes place in multiple contexts. Key contexts from birth to age 10 include: caregiver relationships; the family, home, and neighborhood; daycare, preschool, and kindergarten; the primary grades of elementary school; peer play and activity groups; classrooms and playgrounds; friendships; and the media (television, music, electronic toys and games, computers, and movies).

 

Figure III-1. Systems that influence child and adolescent behavior. This schematic represents the multiple systems within which children and adolescents are embedded. Their relative influence varies across development.

Figure III-1. Systems that influence child and adolescent behavior.
Source: Surgeon General's Call to Action to Prevent and Reduce Underage Drinking (http://www.surgeongeneral.gov/topics/underagedrinking/calltoaction.pdf)

 

B. Epidemiology

There is little information available on alcohol use by those aged 10 and under. Only limited survey data are available and retrospective recall by adolescents about early drinking is not very reliable, with the age of first use increasing the older the adolescents are when questioned.

According to the most recent Partnership Attitude Tracking Study (1999 PATS; sponsored by the Partnership for a Drug-Free America) which surveyed a national probability sample of nearly 2,400 youth, 9.8% of 4th graders, 16.1% of 5th graders, and 29.4% of 6th graders had had more than just a sip of alcohol in their life. According to the 2003-2004 PRIDE Survey, which summarizes school district surveys performed across the U.S., 4.2% of 4th graders, 5.6% of 5th graders, and 8.7% of 6th graders had consumed a beer in the past year. Slightly more had consumed wine coolers (4.4%, 6.7%, and 10.3%, respectively), and approximately half as many reported drinking liquor in the past year (1.9%, 2.8%, and 5.2%, respectively). The PRIDE data are based on a large convenience sample of children from many school districts across the country rather than on a representative national sample and so contain an unknown level of bias. (Note that most 4th graders are 9 or 10 years old and some 5th graders are 10 years old.)

There is little evidence that children under 10 have alcohol abuse or alcohol dependence problems, despite some clinical reports and anecdotal stories of child alcoholics. In the few studies that examined very early alcohol abuse and dependence, rates of diagnosed alcohol use disorders was close to zero in the general population, but other studies have found alcohol problems among youth under 10. For example, one study found that 0.5% of fourth graders in rural New Hampshire qualified as problem drinkers, which was defined as drinking at least once a month and having been drunk to the point of falling down or vomiting.

C. Etiology

 

Non-specific to Alcohol Risk Factors in Childhood. A number of non-specific-to alcohol risk factors from birth to age 10 predict the early onset of drinking and the development of alcohol problems and alcohol use disorders in adolescence or adulthood. These risk factors for subsequent alcohol involvement are considered nonspecific because they also influence a broad range of other behavioral outcomes. The primary non-specific risk factors include the following:

Because of this cluster of non-specific factors, the pre-pubertal period is important for understanding and preventing adolescent alcohol use. There is evidence, for example, that some risk factors for later alcohol dependence can be identified as early as age three.

The Externalizing Pathway. Children who show early difficulties with impulse control and paying attention, exhibit unusually high levels of aggression during the preschool years, and develop early academic problems related to their behavior once they are in school are said to exhibit externalizing behaviors. During late childhood and early adolescence, some of these children disengage from school, begin to associate with deviant peers, engage in increasingly risky behaviors, and become involved in delinquent behavior. These same youth are at high risk for early alcohol use and other negative behaviors, including early and risky sexual activities and truancy.

The Internalizing Pathway. A second pathway toward underage drinking that may have its beginnings in childhood is associated with depressive spectrum disorders and related antecedents, including anxiety and shy/inhibited personality. The evidence is weaker for this internalizing pathway in relation to earlier alcohol use than for the externalizing pathway. However, there does appear to be a link between depression in adolescence and risk for alcohol initiation and considerably stronger evidence for an internalizing pathway to alcohol use disorders.

Alcohol-Specific Risk Factors in Childhood. The dynamic interplay of biological, psychological, and social processes from birth through age 10 shapes overall development including the risk for alcohol problems. Research has identified a number of risk factors that can be identified between birth and age 10 that predict risk for later alcohol use and abuse. Unlike non-specific risk factors that predict a spectrum of problems as well as alcohol use, these risk factors are specific to alcohol. They include:

Development of Children's Beliefs and Expectancies about Alcohol. As they develop, children become aware of alcohol as an object in their social environment through a variety of mechanisms. These include drinking by their parents and other adults in the family context as well as alcohol use by adolescents and adults portrayed in the mass media (television, movies, print media, and advertising). In the absence of their own experience with alcohol, this vicarious learning is the major influence on children's attitudes toward alcohol and their expectancies about the effects of drinking. As children grow older, they learn that alcohol produces changes in cognition, feeling, and behavior and that it has a role in social relationships. They discover who uses it and why, and, ultimately, develop expectancies about its use.

Expectancies about alcohol and its use have been shown to play an important role in determining if and when youth will consume alcohol, and how much they will consume if they choose to drink. Studies of normal samples over a twenty-year period show that children's ratings of adults depicted drinking alcohol are basically neutral at age 6, and become more negative until about age 10. In one recent study, the researchers found that between ages 8 and 12, both positive and negative expectancies increase suggesting increasing ambivalence about the effects of alcohol. A number of studies indicate that between ages 10 and 14, children's attitudes about alcohol become more positive. This is important because positive expectancies have been shown to predict onset of drinking in adolescence.

The Role of Childhood Social Contexts in the Risk for Drinking. Parents are a major source of children’s exposure to alcohol use. When children are asked the source of their first drink, they overwhelmingly cite their parents or home. For example, 78% of the third- through sixth-grade children participating in the 1993-94 Bogalusa Heart Study who had tried alcohol took their first drink with someone in the family. Among children, self-reports of alcohol use correlate significantly with child perceptions of parental drinking. Research over the past 40 years consistently shows that children are more likely to eventually become drinkers if their parents are drinkers.

In addition to their observation of parental drinking, children learn about alcohol use and its effects through their exposure to movies, television content, and advertisements. On average, children aged 2-11 saw 99.4 alcohol advertisements on television between January and October of 2004 (81% for beer and ale, 11% for spirits, 5% for alcopops, 3% for wine). Alcohol advertisements are not the only source of alcohol portrayals on television, however. Portrayals of alcohol use (and typically its lack of consequences) are common on television programs aired in prime time (8-11pm) when children may be watching. An estimated 71% of sampled episodes from the 1998-99 season included alcohol use by characters on the shows. Approximately 38% of the shows with a TV-G rating, which makes them appropriate for most children, depicted alcohol use. More episodes characterized drinking as a positive experience rather than a negative experience. Negative consequences were portrayed or mentioned in only 23% of the episodes. Moreover, a recent study provides evidence for an association between exposure to movie alcohol use and early-onset teen drinking.

Children in Alcoholic Families and/or with a Family History of Alcohol Dependence. According to National Longitudinal Alcohol Epidemiologic Survey (NLAES) data approximately 6.8 million children age 11 or younger were living in households with one or more adults classified as having a current diagnosis of alcohol abuse or dependence and thereby would meet the formal definition of children of alcoholics (COA). Children of alcoholics are between 4 and 10 times as likely to develop alcohol dependence themselves. But prior to that, they are also at elevated risk for earlier onset of drinking and for earlier progression into drinking problems.

Some of the elevated risk of the COA is attributable to environmental risk, including exposure to an alcoholic parent as well as socialization effects found in alcoholic households, some to genetically transmitted differences in response to alcohol that make drinking more pleasurable and/or less aversive, and some to elevated transmission of risky temperamental and behavioral traits that lead the COA into greater contact with earlier and heavier drinking peers. Both genetic vulnerability and environmental risk are important as are the length of exposure and the developmental period(s) during which the exposure(s) take place. For example, studies show that children with an alcoholic biological parent who were raised by non-alcoholic adoptive parents were still significantly more likely to develop alcoholism later in life than were control children with no genetic risk for alcoholism. In addition, a substantial number of alcoholic men marry alcoholic women further compounding risk for their offspring through increased genetic exposure and impaired martial interactions. Environmental risk for COAs involves both familial and neighborhood exposure. Families with an alcoholic member tend to be more dysfunctional and experience higher levels of psychiatric comorbidity. They are also more likely to be poor and to live in poorer neighborhoods where the risk of a child's exposure to deviant peers is higher.

Fetal Alcohol Exposure. An additional potential risk for early onset drinking as well as for the development of risk factors for later alcohol problems is the exposure of the child to alcohol in utero. Given the number of alcoholic men who marry women with the same problem, some children will be affected not only by genetic risk and by socialization risk associated with being a child of alcoholic parents, but also by the risk arising from the effects of heavy alcohol exposure during fetal development (i.e., teratogenic effects). The teratogenic risks are discussed in detail in the section on the Fetus. What is relevant for this age group is the possibility that prenatal alcohol exposure itself increases the risk of the exposed child for developing alcohol problems of his own.

D. Prevention and Intervention

Resilience. Considerable evidence indicates that later alcohol use can be predicted from developmental patterns evident well before 10 years of age, suggesting that young children have already started down developmental paths leading toward or away from early use and abuse of alcohol. In some cases, high risk pathways are so well established that these pathways are clear targets for preventive intervention, although such pathways are always probabilistic and not certain roads to underage drinking. In fact, there are children who appear to be on the same high-risk pathways who do not begin to drink early or who take a turn for better development.

Protective and Promotive Factors. "Protective factor" has had two meanings in the literature on risk and resilience. The first meaning refers to a positive correlate of a desirable outcome (i.e., it is a simple predictor of better outcomes). For alcohol use, therefore, a protective factor is one that predicts lower rates of use or dependence (i.e., it is negatively correlated to the outcome). With this definition, a bipolar predictor of the outcomes could be labeled either as a risk or a protective factor depending on how it is scored or named. Parenting is a classic example, where good parenting can be viewed as a protective factor, and bad parenting can be viewed as a risk factor for underage drinking. Rearing environments that are high in warmth, moderate in discipline, and lower in stress level are the most effective in instituting lower levels of externalizing behavior in children and adolescents, and ultimately, in producing lower drug involvement in adolescence. Parents who are responsive to their child's needs gradually increase the self regulatory capacity of the child.

The second meaning of protective factor refers to a factor that has a buffering effect on the outcome, so that the factor is associated with better-than-expected outcomes in the context of risk. For alcohol use, such a factor would be associated with lower-than-expected alcohol-related outcomes given the level of risk for alcohol use or AUDs present in the individual. Thus, among children living in poverty in bad neighborhoods surrounded by deviant peers who encourage underage drinking (where risk for underage drinking appears to be high), effective parenting may be particularly important and may have protective effects beyond the generally positive effects of good parenting on child outcomes. These concepts are clarified in the resilience literature, where the term "promotive" factor is often used to mean a simple predictor of risk and "protective" factor is one that plays a moderating role when risk is present. Little research has been performed to establish the operation of protective factors among children under the age of 10 years.

Developmentally Influenced Interventions

A number of opportunities exist for developmentally-related interventions prior to the initiation of alcohol use in childhood. These interventions focus not only on the children but on their parents as well.

Child-Focused Interventions

1. Among those children identified as having prenatal exposure to alcohol, early childhood interventions should be instituted prior to school entry. Such interventions should teach child and parental behaviors that improve the child’s functioning at academic tasks, enhance response inhibition, and reduce inattention.

2. Better surveillance systems in the schools, pediatric medicine, social services, and public safety (police) will identify children already displaying evidence of externalizing disorders, which are risk factors for earlier onset of drinking and the development of alcohol problems in adolescence.
3. Develop a program to enhance or enable collaboration between alcohol researchers and other developmental researchers in allied fields who may already have successful prevention or intervention programs to reduce conduct problems in children and preadolescents. Important considerations would include determining at what ages interventions are likely to be most efficacious, what are the most engaging and least stigmatizing venues for such interventions, and how best to reduce barriers to parental involvement in the programs.
4. Although childhood onset of alcohol use is less likely affected by affiliation with deviant peers, associating with such peers is a major risk factor for early adolescent onset of drinking and for movement into problematic drinking in adolescence. The pathways toward later affiliation with deviant peers begin in childhood and are influenced by a variety of family risk factors, including harsh and inconsistent discipline, low levels of parental warmth, low parental support, less parental monitoring, and low parental attachment and identification. Research suggests that the most effective interventions involve parent education in school family resource centers, rather than child interventions that group and segregate children at risk.
Parent-Focused Interventions
The goal in parent-focused interventions is to make the intergenerational transmission of alcoholism less likely. Given the importance of genetic risk for alcoholism and its associated socialization risks, these interventions:
1. Emphasize treatment for the alcoholic parent(s) to reduce the parent's problem drinking and thereby reduce the children's exposure to such drinking in the home
2. Train parents in more effective parenting practices to reduce instances of child neglect and maltreatment
3. Provide marital or couples' counseling to reduce conflict in the home. Such parental training and counseling should be offered as part of the parents' alcoholism treatment.

E. Opportunities

A number of significant research opportunities and directions exist for the birth to age ten years group. The first two are of importance since there is little to no information in these areas. The third is also of importance as there is a need to better understand why drinking is a normative behavior among American adolescents and how drinking becomes so widespread among youth. The remaining opportunities represent areas where increased knowledge about known developmental pathways into alcohol use and AUDs will enhance prevention efforts with specific groups of youth at high risk.

In some cases, familial, neighborhood, and peer structures act in concert to encourage the development of early involvement with alcohol. Determine the degree to which these concurrent risk factors are synergistic for the development of risk.

F. Outreach

 

Outreach activities for the Birth to Age Ten category are located in the Youth/Adolescence Outreach section.

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CHAPTER IV. Youth/Adolescence

 

A. Definition of Youth and Adolescence

 

Adolescence is a period of life characterized by dramatic changes in biological processes, as well as physical and social contexts. For the purpose of this document, we define the age range of adolescence as spanning the period between 12-17 years old. There are many factors that impinge on the development of the individual as they progress through the adolescent period. Biological changes include substantial physical growth, endocrine changes, and brain maturation that continue into the third decade of life. Important psychosocial changes include spending more time with peers and less time with family, a change in the level and type or supervision (parental or otherwise), the development of sexuality and romantic interests, and increasing independence and self-reliance. At the same time, the environments with which youth interact - schools, peers, parents and family, neighborhoods and the larger society– are changing as are the multiple ways in which youth interface with and relate to these environments. As youth traverse this complex period of life, they are expected to successfully negotiate important transitions (such as from elementary to middle school and from middle school to high school), take on new roles (such as employee), master new tasks (such as driving), develop increased self-regulation, and set long-term goals. During this time the majority of youth begin to drink (80% by the end of high school), and some experience significant alcohol-related problems including the development of alcohol use disorders.

The beginning of adolescence is demarcated biologically with the onset of puberty, and, by convention, is understood to end when an individual assumes adult roles and responsibilities. Puberty was once thought to be initiated by hormonal events triggered by neuroendocrine changes in the brain. Furthermore, puberty is not a single entity, but consists of many biological processes that may not occur at the same time, and do not necessarily progress at the same pace or have the same pattern of unfolding. As already mentioned the brain itself continues to mature during adolescence and into the mid 20s with early adolescence marked by proliferation of neurons and connections between neurons and later adolescence characterized by pruning of neural connections and increased myelination. Very important to understanding alcohol use by youth from a developmental perspective is the fact that, over the past 100 years, the endocrine changes associated with puberty have been occurring at younger ages, while the attainment of adult roles such as starting a career, finding a partner, owning a home and becoming a parent are occurring much later. The result is the dramatic expansion of the period referred to as adolescence.

Adolescents are the healthiest cohort in the population in terms of organic disease but, at the same time, they experience relatively high rates of mortality and morbidity due to their behavior, including the use of alcohol. Across many species including humans, adolescence is a time of heightened risk-taking and for many young people in our society, some of that risk-taking involves alcohol use. Further, adolescence is a period of increasing socialization often involving alcohol. For some, the increased social demands of adolescence may be accompanied by increased anxiety heightening the risk for alcohol use. In this way, alcohol use has become intertwined with the normal developmental processes of adolescence. And alcohol use both affects development and is affected by developmental processes. Therefore, an overarching developmental framework will provide a useful vantage point for advancing our understanding of underage drinking.

 

B. Epidemiology

Alcohol is the drug of choice among youth, used by far more young people than cigarettes, marijuana, or illicit drugs (see Figure IV-1)

 

Figure IV-1. Alcohol as the Drug of Choice Among Youth

Alcohol as the Drug of Choice Among Youth

Source: SAMHSA 2002 National Survey on Drug Use and Health (NSDUH) data

As a result, underage drinking is a leading public health problem in this country, as young people create problems for themselves, for people around them, and for society as a whole by drinking too much, too often, at too early an age. A number of studies have found that early initiation of alcohol use (usually defined as starting to drink at age 13 or younger) is a risk factor for escalation of alcohol use in adolescence, and that both are risk factors for the development of alcohol-related problems in adulthood.

Nationwide surveys indicate that adolescent males and females between the ages of 12 and 17 have similar patterns of alcohol use (frequency and quantity) as well as prevalence of DSM-IV alcohol abuse and dependence. By late puberty, however, sex specific patterns and prevalence begin to diverge, with females exhibiting fewer drinking days in the past month, fewer episodes of heavy drinking, and lower prevalence of alcohol abuse and dependence. Research also suggests that early puberty, particularly in girls, is associated with higher rates of substance use and abuse (including alcohol) independent of age and school grade. The usual interpretation of this finding is that social factors and environmental stressors mediate the relationship between maturational changes during puberty and the onset of alcohol/substance use. However, hormonal mechanisms that could explain the progression of sex differences in alcohol drinking patterns during puberty, such as activation of reproductive hormones, stress responses, and their effects on brain developmental processes, remain relatively unexplored.

Even though this chapter focuses on youth from ages 12-17 and their alcohol consumption and consequences, it is important to note that alcohol is a leading cause of death for people under age 21. Each year, approximately 5,000 persons under the age of 21 die from causes related to underage drinking. These deaths include about 1,500 homicides and 300 suicides. Alcohol is also often associated with unintentional burns, falls, drownings, and other fatal and non-fatal events, and is a frequent factor in physical and sexual assault and in unwanted/unintended sexual activity. Underage drinking also causes second-hand consequences. Half of all persons who die in traffic crashes involving drinking drivers under age 21are persons other than the drinking driver. Among college students under age 21 alone, 50,000 experience alcohol-related date rape, and 43,000 are injured by another student who has been drinking.

While the prevalence of drinking among youth has decreased since the 1970s, available information from a number of national surveys indicates that rates of consumption have remained stable, at quite high levels, during the past decade.

Particularly worrisome among adolescents is the high prevalence of binge drinking. In fact, the majority of youth who drink are binge drinkers. In the figure, below, heavy drinkers are those who binge drink five times a month or more, so among youth who drink, 60.5% binge drink (see Figure IV-2).

 

Figure IV-2. Three Broad Types of Drinkers

Figure IV-2. Three Broad Types of Drinkers

Source: SAMHSA 2002 NSDUH data. Data based on responses to questions about drinking within the past 30 days from 4.37 million adolescents ages 12-17.

Underage drinkers consume, on average, 4 to 5 drinks per occasion about 5 times a month. By comparison, drinkers age 26 and older consume 2 to 3 drinks per occasion, about 9 times a month (see Figure IV-3).

Figure IV-3. Frequency vs. Quantity of Alcohol Consumption in Youth

SFigure IV-3. Frequency vs. Quantity of Alcohol Consumption in Youth

Source: SAMHSA 2000 National Household Survey on Drug Abuse (NHSDA)

The U.S is not unique with regard to the problem of underage drinking. Alcohol use and misuse by youth is an international phenomenon (see Figure IV-4).

Figure IV-4. Frequency of Alcohol Use and Drinking to Intoxication During Past 12 Months in Youth Across Nations

Frequency of Alcohol Use and Drinking to Intoxication During Past 12 Months in Youth Across Nations

Source: The European School Survey Project on Alcohol and Other Drugs, 2003 ( http://www.espad.org/ ) (thick vertical bar represents the percent of 15 year olds performing that action in the United States)

 

C. Biology

Adolescence is a period of rapid growth and physical change; a central question is whether consuming alcohol during this stage can alter development in ways that have long-term consequences. As noted above, brain development and maturation continue during adolescence, and even into the mid 20s. Limited research with animals and humans suggests that alcohol may perturb normal brain development in adolescence and young adulthood, thereby altering neurophysiology and associated behavioral functioning.

Imaging studies have shown that the hippocampus, a brain region that plays an important role in learning and memory, is smaller in adolescents who begin drinking at an earlier age than in those who begin drinking later. Researchers have found that memory problems are common among adolescents in treatment for alcohol withdrawal. Since so many youth use alcohol on a regular basis, and often in a "binge" pattern of consumption, we must understand more about the impact of alcohol on the physiological, neurophysiological and functional development of the brain. In general, adolescents are less sensitive to the acute, negative effects of alcohol, such as sedation and motor impairment, which would normally serve to limit alcohol consumption. This may partially explain the heavy, binge-like pattern of drinking undertaken by adolescents. However, on tasks with which youth are unfamiliar or less experienced, such as driving a motor vehicle, they are more susceptible to the negative effects of alcohol (this effect could be due to processes related to state dependent learning or the development of tolerance).The heavy, binge pattern of alcohol consumption places adolescents in repeated exposures to, and withdrawals from, the high (medically damaging) concentrations of alcohol that are thought to make individuals more vulnerable to alcohol's detrimental and toxic effects. Although withdrawal symptoms normally associated with abstinence from alcohol abuse are rare in adolescents, subsyndromal effects from binge-like alcohol exposure may still initiate harmful consequences.

D. Prevention

Prevention of alcohol problems in adolescents poses special challenges due to the unique physical, psychological, and social maturation processes occurring during this period. As the developing adolescent advances through middle/junior high and high school, and becomes active in sports and other after-school activities, he or she will likely be granted more freedom of movement and use of discretionary time, and have access to resources like money and a motor vehicle. As greater degrees of independence are obtained, the adolescent becomes exposed in a greater degree to the influences of the larger culture, including significant peer pressure, which becomes increasingly important in shaping attitudes, beliefs and tastes in clothing, music, and behavior. These intense pressures on the adolescent, in combination with their developing attitudes and beliefs, make them "moving targets" for intervention and treatment. These external influences may, or may not, be in synchrony with the competencies, interests, and capacities of any particular adolescent. In tandem with these biological and environmental changes, progressive demands are made on the developing youth for academic progress, self-regulation, and self-governance, in the face of increasing freedom to choose one's own day-to-day and life directions. Recent studies point to developmental processes intrinsic to adolescence that may support or even encourage alcohol use, abuse, and dependence. The challenge is then to reduce underage drinking despite strong psychosocial influences that may lead young people toward alcohol use since long-term consequences may result from alcohol exposure during this time of accelerated neural, endocrine, behavioral and social maturation.

Current prevention efforts approach the issue of youth drinking in two ways. Environmental-level interventions seek to reduce the availability of alcohol to youth and opportunities to drink, increase penalties for violation of minimum legal drinking age laws, and reduce community tolerance for alcohol use by youth. Individual-level interventions seek to change knowledge, attitudes, and skills so that youth are better able to resist influences that support drinking.

At the environmental level, the most comprehensive interventions to date encompass coordinated school, family, and community programs. One such universal prevention program, implemented in the last decade called Project Northland, included school curricula, peer leadership, parental involvement programs, and communitywide efforts to address community norms and alcohol availability. The intervention was delivered to a single cohort from grades 6 through 12. Comparisons in such measures as "tendency to use alcohol" and drinking five or more drinks in a row revealed differences between intervention and comparison communities.

At the individual level, the ability of parents to influence whether their children drink is well documented and is consistent across racial/ethnic groups. Family interventions encourage parents to be aware of the risks from underage drinking, communicate with children, clarify expectations, set rules and consequences about alcohol use, and monitor children's activities. In addition to changing the knowledge and skills of young people, families can create an environment that reduces alcohol availability and increases the costs associated with drinking.

Another type of individual intervention uses the contact time with the medical system following an alcohol-related adverse event that represents a "teachable moment" Recent studies in pediatric and other emergency departments and with college age and other populations have indicated screening and brief interventions can reduce current drinking and related problems. For example, in a study of alcohol-involved teens in an urgent care setting, those who participated in a brief motivational interview showed significantly greater improvement as reflected in significantly lower incidence of drinking and driving, fewer alcohol-related social and legal problems, and fewer alcohol-related injuries during follow-up compared to those receiving standard care. Another study in a similar population found that those adolescents receiving a brief motivational intervention had significantly fewer drinking days per month and lower frequency of high-volume drinking compared with adolescents who received standard care.

E. Treatment

The rates of problematic drinking and serious consequences are high among adolescents, and many have problems, such as alcohol dependence, appropriate for intervention by the alcoholism treatment system. Data from the National Household Survey indicate that 1.47 million youth ages 12-17 met the criteria for alcohol dependence or alcohol abuse in 2003 (5.9% of adolescents in this age group). The same survey showed a major unmet need for alcohol treatment in this group. Only 216,000 (15%) received any type of treatment for their alcohol problem (see Table IV-1).

Table IV-1. Percent Youth Meeting DSM-IV Criteria for Alcohol Dependence and Seeking Treatment

Alcohol Dependent
Seeking Treatment
Ages 12-17
5.9%
15%
Source: National Household Survey, 2003

 

Youth prefer easy access, low threshold approaches that accentuate strategies adolescents normally use to stop drinking and treatments that do not remove them from their primary home or academic settings. Youth perceive traditional services (e.g., alcoholism treatment programs, Alcoholics Anonymous) as less helpful than brief interventions tailored to salient adolescent concerns. Consequently, alternative formats, attention to developmental transitions, and use of social marketing are needed to more adequately address alcohol problems emerging in adolescence.

Adolescents in treatment for alcohol use disorders (AUDs) are likely to have more than one substance use disorder and may have other psychiatric co-morbidities; the success of treatment is lower with those who have multiple problems than with other subgroups of youth. To date, treatment for adolescent addiction has involved adapting adult treatments to youth. Ongoing research is testing some innovative and developmentally tailored interventions aimed at improving treatment outcomes.

Research has shown that adolescents in treatment for alcohol dependence have deficits in neural function and structure demonstrated through neuropsychological assessments and structural imaging. The question of whether the adolescent brain is more or less vulnerable than the adult brain to alcohol's acute and chronic effects remains to be determined. Recovery of function may also provide insight on whether such deficits may have been causative rather than consequential to the development of the alcohol use disorder.

The changes that occur in the endocrine systems during adolescence may significantly contribute in processes associated with the development of alcohol problems. Therefore, an important element for research investigation is to identify the relationship among reproductive hormones, stress hormones, and sex differences in alcohol use and dependence that unfolds during late puberty.

F. Opportunities

Correlate changes in brain structure and function with neuropsychological functioning using current and newly emerging neuropsychological tools from the NIH Normal Brain Development Project.
Research in this area needs to be pursued through the expansion of investigations on the adolescent decisional process overall, and the influence of affect, external environmental factors, and expectations on those decisions. Important in the context of alcohol use is the observation that alcohol is typically used in a social rather than an individual context, by both adolescents and adults (with the exception of those who have become physically dependent on alcohol). Examining the interplay of environment, and biological traits related to temperament, and socialization, through longitudinal research and clinical study, is a direction that may uncover important factors in decisional processes about alcohol. These human studies can employ the use of time-line follow backs as one tool to assess decisional changes.
Some of the needed decision making investigations can be carried out in laboratory simulated environments similar to those used in other human decision making research. In addition, animal research, particularly in primates, can be used to examine decisional processes related to alcohol. Through such investigations, it may also be possible to understand how alcohol affects the valence of the various factors that contribute to decision making in adolescence and whether those effects are different for adolescents than they are for adults.
G. Outreach
The preceding two sections of the NIAAA Strategic Plan have provided research information pertaining to drinking by young people in two broad age groups: Birth to Age 10 and Youth/Adolescence (~ages 12-17). The NIAAA outreach activities for these two age groups are presented in this particular section because they target young people of both ages, and the adults who interface with them. NIAAA's Underage Drinking Research Initiative has framed the issue of underage drinking in a developmental context. This framework also informs NIAAA's outreach approach. While some materials and activities are best suited to a particular age group, many are appropriate for both children and adolescents, and their parents.

H. Collaborations

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A. Definition of Young Adult

Many factors contribute to the definition of young adult. For this purpose, the ages of 18-29 are used to delineate this period, although this time frame can be further broken down into 18-24, and 25-29. For example, the late teens and early 20s see the completion of major maturational changes to the prefrontal cortex of the brain and optimization of goal-directed behavior, yet the transition from adolescence to early adulthood is not otherwise demarcated by the kind of overt biological events that typify entry into adolescence. Rather, young adulthood entry into this life stage has come to be defined by a variety of self-directed transitions that signal an individual's burgeoning independence from parental care. The pursuit of post-secondary education, enlisting in the military, and entering the workforce are a few such milestones, which traditionally have occurred when an individual is in his or her late teens or early twenties. Other events that traditionally mark this period include assuming large financial obligations, courtship, and marriage. In the U.S, most states have adopted age 18 as the legal age of majority -- the point at which individuals assume responsibility for their own actions. However, from a developmental rather than a legal perspective, emerging or young adulthood now comprises an extended period of unsettled behavior for many individuals, as age of marriage and age of career initiation in the U.S., for example, have increased relative to historic norms.

Table V-1. Percentage of U.S. Adults 18 and Over with Past-year Alcohol Abuse or Dependence and Percentage of Those with Past-year Abuse or Dependence Who Received Alcohol Treatment, by Type of Treatment

Past-year disorder
Type of treatment
Age group

Abuse

Dependence
Any treatment
12-Step only
Other only
12-Step and other
18-297.0 (0.4)
9.2 (0.4)
5.9 (0.7)
1.3 (0.4)
2.3 (0.4)
2.3 (0.5)

18-24

6.7 (0.5)
11.6 (0.6)
6.4 (0.9)
1.4 (0.5)
2.8 (0.6)
2.2 (0.6)
25-29
7.3 (0.6)
5.7 (0.4)

4.9 (1.2)

1.0 (0.5)
1.2 (0.5)
2.7 (0.9)
Source: Adapted from Table I-8 in the Overview.

 

Compared to all other age groups, the prevalence of periodic heavy or high-risk drinking is greatest among young adults aged 18 to 24. Alcohol use disorders, including alcohol dependence, also peak during this period (see Table V-1 above). While most young adults transition out of harmful drinking behaviors, a minority will continue to drink heavily into the later stages of adulthood. For example, recent NESARC data has shown that, while the prevalence of past-year DSM-IV alcohol dependence is more than 12 percent for 18-20 year olds and more than 10 percent for 21-24 year olds, by age 25-29 prevalence has dropped to less than 6 percent and is less than 4 percent for adults ages 35 and over (see Figure V-1). These phenomena raise important research questions. For example, what factors allow some young adults to discontinue harmful drinking patterns, most often in the absence of formal alcoholism treatment? Why do others experience protracted alcohol problems well into their adulthood?

 

Figure V-1. Prevalence of Past-year DSM-IV Alcohol Dependence by Age in the United States
Figure V-1. Prevalence of Past-year DSM-IV Alcohol Dependence by Age in the United States
Source: NIAAA 2001-2002 NESARC data (18-60+ years of age) and SAMHSA 2003 NSDUH (12-17 years of age)

 

B. Epidemiology
Figure V-2 illustrates that problematic drinking behaviors are prevalent among college, non-college, military, and civilian young adult populations. A recent review by NIAAA researchers found that from 1998 to 2001 the nationwide number of alcohol-related deaths among 18--24-year-olds rose at a rate that significantly exceeded that age group's proportional population increase. Whereas the population increased 7% from just over 26 million to almost 28 million, alcohol-related unintentional injury deaths rose 12% from 4771 to 5367. Thus, alcohol-related deaths per population of 18--24-year-olds rose 5% from 1998 to 2001.

 

Figure V-2. Prevalence of Heavy and Binge Drinking in Young Adults by Specific Institution (Military, College)
Figure V-2. Prevalence of Heavy and Binge Drinking in Young Adults by Specific Institution (Military, College)

Source: Ames and Cunradi. Alcohol Use and Preventing Alcohol-Related Problems Among Young Adults in the Military Alcohol Res Health 28: 252-257, 2005. (Military data: Bray, et al., 2003; Civilian data: SAMHSA 2002 NSDUH)

According to NESARC data, in 2001-2002 over three-quarters of young adults ages 21-24 were current drinkers, as were nearly two-thirds of those ages 18-20, despite the fact that the legal drinking age is 21. More than half of young adult men exceeded the recommended daily drinking limit, as did two-fifths of young adult women (see Figure V-3). Although the prevalence of exceeding the daily limit is higher for those ages 21-24 than for those ages 18-20, it also is substantial for those ages 18-20. Because drinking more than the recommended per-occasion maximum is likely to impair mental and physical performance, the increase over the past decade in the prevalence among young adults of drinking five or more drinks 12 or more times per year may help explain the increased risk of injury and other acute negative consequences commonly observed among college students ages 18-24.

Of the various sub-populations of young adults, college students have received perhaps the greatest research scrutiny regarding alcohol consumption in recent years. As we have learned much about alcohol use in the transitional roles through college, there is a need to expand our knowledge on the similarities and differences that occur among the young adults who enter the military or the workforce. We must also continue to explore similarities and differences in drinking behaviors of young adults from different racial and ethnic sub-populations.

Figure V-3. Percentage of Individuals Exceeding the Daily Drinking Limit for Ages 18-20 and 21-24, by Gender, Race-Ethnicity, and College Enrollment Status
Percentage of Individuals Exceeding the Daily Drinking Limit for Ages 18-20 and 21-24, by Gender, Race-Ethnicity, and College Enrollment Status
Source: NIAAA 2001-2002 NESARC data. AIAN = American Indian/Alaska Native, ** NHOPI = Native Hawaiian/Other Pacific Islander

College

Research on the college-attending population has shown that some 1,700 college students between the ages of 18 and 24 die every year as a result of hazardous drinking. In addition, nearly 600,000 college students suffer unintentional injuries under the influence of alcohol, and another 700,000 are assaulted by fellow drinking students. Alcohol-related assaults include nearly 100,000 sexually assaults or date rapes.

The proportion of college students who drink varies with where they live. Drinking rates are highest in fraternities and sororities followed by on-campus housing (e.g., dormitories, residence halls). Students who live independently off-site (e.g., in apartments) drink less, while commuting students who live with their families drink the least.

Although the existing literature on the influence of collegiate environmental factors on student drinking is limited, a number of environmental influences working in concert with other factors may affect students' alcohol consumption. Colleges and universities where excessive alcohol use is more likely to occur include schools where Greek systems dominate (i.e., fraternities, sororities), schools where athletic teams are prominent, and schools located in the Northeast.

Some first-year students who live on campus may be at particular risk for alcohol misuse. During their high school years, those who go on to college tend to drink less than their noncollege-bound peers. But during the first few years following high school, the heavy drinking rates of college students surpass those of their noncollege peers, and this rapid increase in heavy drinking over a relatively short period of time can contribute to problems with alcohol and with the college transition in general.

Military and Non-College Civilians

Researchers have noted that heavy drinking is common among those who enlist in the military. A study that tracked high school students into adulthood found that those who entered the military were more likely than other young adults to have been heavy drinkers in high school.

A 2002 survey by the Department of Defense found that, among the 193,000 active duty military personnel between the ages of 17 and 20, 26 percent are heavy drinkers who consume five or more drinks per drinking occasion at least once a week. As shown in the table below (Table V-2), a comparison of data from military and civilian surveys found that rates of heavy drinking among 18- to 25-year-olds in the military are higher than for civilians of the same age (32 percent vs. 18 percent for men and 8 percent vs. 5 percent for women).

Table V-2. Standardized Comparisons of the Prevalence of Heavy Alcohol Usea Among 18- to 25-Year-Old Military Personnel and Civilians, Past 30 Days, by Gender, 2001-2002

 

Comparison Population

Gender

Civilian

Total DOD

Males

17.8% (0.5)

32.2% (2.3)b

Females

5.5% (0.3)

8.1% (1.0)b

In Total Population

15.3% (0.4)

27.3% (2.1)b

 

Source: Ames and Cunradi. Alcohol Use and Preventing Alcohol-Related Problems Among Young Adults in the Military Alcohol Res Health 28: 252-257, 2005. (Military data: Bray, et al., 2003; Civilian data: SAMHSA 2003 NSDUH)

NOTE: Table entries are percentages, with standard errors in parentheses. Civilian data have been standardized to the U.S.-based military data by gender, age, education, race/ethnicity, and marital status. Data for the total Department of Defense and the individual services are U.S.-based population estimates (including personnel in Alaska and Hawaii).

a Defined as consumption of five or more drinks on the same occasion at least once a week in the past 30 days.

b Significantly different from the civilian estimate at the 95-percent confidence interval.

C. Biology

Research in college students has found short-term health-related consequences of heavy drinking such as hangovers, nausea and vomiting are experienced by a large minority, if not the majority, of such students. One survey of students at 89 schools across the nation produced a self-report result of 40% with at least one hangover (47% of drinkers) and 47% (56% of drinkers) having nausea or vomiting as a result of alcohol or other drug use within the year. In one study at a New England university where almost all students (97%) drank alcohol within the year, 29% of the student sample reported that anywhere from one-half to 24 hours of their normal functioning were lost "in recovery" from drinking in the last week. Alcohol poisoning, alcohol-induced coma, and the fatal outcomes resulting from extremely high blood alcohol levels induced by excessive alcohol consumption are occasional, but not unfamiliar incidents in campus health centers and local hospital emergency rooms, although systematically collected data on the prevalence of student alcohol poisoning are not available in the research literature.

Longer term consequences of heavy alcohol use to one's health may include reduced resistance to illnesses. Self-reported illnesses were correlated with drinks consumed per week among undergraduates enrolled in a general education course at a large mid-western university. Although light to moderate consumption was not significantly associated with increased health risks, consuming an average of 22 drinks or more per week was associated with increased upper respiratory infections, and consuming 28 drinks or more was associated with greater acute illness on an aggregate measure, thus suggesting that heavy alcohol consumption contributes to lowered resistance to common illnesses among students.

With respect to young adults in the military, one study found that the highest levels of negative effects—serious consequences (e.g., missing a week or more of duty because of a drinking-related illness or being arrested for driving while impaired), productivity loss, and dependence symptoms—occurred among military personnel in the lowest pay grades. Other serious consequences included not being promoted, receiving a low performance rating, being arrested for another alcohol-related reason, being involved in a traffic crash resulting in injury or property damage, and fighting while drinking. These pay grades generally correspond to the youngest enlisted service members, who typically lack a college education. During 2002, 20.2 percent of junior enlisted personnel reported serious alcohol-related consequences, 27.2 percent reported lost productivity, and 22.6 percent reported symptoms of dependence.

D. Prevention and Treatment

Researchers have noted that young adults rarely identify themselves as problem drinkers, suggesting that proactive screening approaches may be necessary to identify problem drinkers in young adult populations.

With respect to college populations, a 2002 review of college drinking prevention strategies found that campuses would best serve the student population by implementing brief, motivational or skills-based interventions, targeting high-risk students identified either through brief screening in health care centers or other campus settings or through membership in an identified risk group (e.g., freshmen, Greek organization members, athletes, mandated students). More recently, researchers have analyzed the effects of interventions on college students. In an examination of a multi-site environmental prevention initiative, investigators reported significant although small improvements in alcohol consumption and related harms at colleges that most closely implemented a particular program model. Other investigators found that environmental DUI campaigns similar to those validated in community prevention trials can be effective in college settings, but noted that further research is needed to determine the robustness of the changes associated with such campaigns. The issue of determining effective strategies for identifying, recruiting and retaining students in efficacious individually focused prevention services remains, as is the determination of the effectiveness of mandated student prevention services.

With respect to young adult military populations, current strategies to prevent alcohol problems include instituting and enforcing policies that regulate alcohol availability and pricing, deglamorizing alcohol use, and promoting personal responsibility and good health. The U.S. military has implemented policies and programs designed to reduce alcohol use and related problems among personnel. However, there has been little formal evaluation of these programs.

Several studies indicate that the non-student population of emerging adults is an important target for preventive interventions, especially because people in this segment of the population may be less likely to mature out of heavy drinking patterns established during adolescence. Although the non-students’ risks for alcohol-related problems in their early twenties may not be as high as those of students’, recent research has shown that the risk for alcohol-related problems in non-student young adults is steadily increasing towards those of college students. Unlike students, however, the risks for non-students appear to increase over time. This population does not have the benefits of campus health care centers or institutionally based programs that college students have. Similarly, students who do not live on campus may not have the benefits of campus alcohol prevention programs (which often are designed for residents) or the protective benefits of campus organizations and peer groups. Furthermore, in addition to limited exposure to alcohol-related services, the non-student/non-military population of individuals may not have exposure to mental health services that are available to the individuals in a structured setting such as college or the military. The lack of access to mental health care or health care in general may predispose these individuals to comorbidities associated with excessive alcohol consumption.

E. Opportunities

F. Outreach

  • Audience segmentation research conducted at NIAAA has revealed that urban-dwelling young adults comprise a major segment of U.S. society that binge drinks two or more times a month. Thus, binge drinking young urban adults are a well-delineated group of individuals at significant risk for alcohol-related problems. This research has also revealed their primary cities of residence, their beliefs, social norms, their mass media viewing habits, their shopping habits, food preferences, health habits and typical sports and leisure activities. Thus, we have rich descriptive data about the lives and habits of binge drinking young adults. This information can provide a strong and unique foundation for programmatic prevention intervention research for these at-risk young adults.

Top

 

CHAPTER VI. Midlife

 

A. Definition of Midlife and Epidemiology

While some may view the underage and young adult life stages as perhaps the most problematic periods for alcohol abuse and dependence, a much more complete spectrum of alcohol-related problems and issues becomes manifested during the adult period of life often referred to as mid-life. At midlife, many of the pathological consequences of heavy alcohol use become most evident, and individuals with alcohol dependence are most likely to seek treatment of their alcoholism at this time.

As with young adulthood, entry into midlife is not signaled by specific biological events. But unlike young adulthood, there is no legal construct analogous to the "age of majority" associated with midlife. Typically, a person in mid-life has assumed one or more "stable" responsibilities of career, marriage, and family life. Chronologically, this period may be viewed as encompassing the 30-59 year old age, but these boundaries are not exact and will vary among different individuals. Table VI-1 shows that percentage of individuals in their midlife meeting criteria for alcohol dependence or alcohol abuse within the past year, at 3 and 5 percent, respectively, and that the percent of those individuals receiving any type of treatment during their lifetime for their alcohol use disorder is only 8.5 percent.

Table VI-1. Percentage of U.S. Adults 18 and Over with Past-year Alcohol Abuse or Dependence and Percentage of Those with Past-year Abuse or Dependence Who Received Alcohol Treatment, by Type of Treatment

Past-year disorder

Type of treatment

Age group

Abuse

Dependence

Any treatment

12-Step only

Other only

12-Step and other

30-59

5.0 (0.2)

3.0 (0.2)

8.5 (0.7)

0.8 (0.2)

3.1 (0.5)

4.5 (0.6)

30-44

6.0 (0.3)

3.8 (0.2)

8.9 (1.0)

0.7 (0.2)

3.2 (0.7)

5.0 (0.8)

45-59

3.9 (0.3)

2.0 (0.2)

7.5 (1.2)

1.0 (0.4)

3.0 (0.8)

3.5 (0.8)

Source: Adapted from Table I-8 in the overview.

B. Biology

Chronic diseases associated with alcohol abuse and alcoholism predominate among mid-life rather than any other age group. Alcohol abuse and alcohol dependence are but two of the disorders that result from the chronic heavy use of alcohol. Many other alcohol-use disorders also manifest in the mid-life stage of life, including several types of alcoholic liver disease, alcoholic pancreatitis, several types of cancer, such as esophageal, larynx, colon, and liver, disorders of the heart and vascular system including alcoholic cardiomyopathy, alcohol-related brain disorders, as well as other adverse effects upon the endocrine and immune system (see Table I-6 in the Overview Section). An alcohol attributable factor (AAF) indicates the relative significance of alcohol as a causal factor in the onset and progression of certain diseases or its role in specific types of injury. Table VI-2 shows that several diseases, including cancer, have an alcohol attributable factor ranging from 25% to 75%, while the alcohol attributable factor for injuries, including those involving motorized vehicles, is just over 40%. These data show that alcohol has a tremendous impact on the human population in a multi-faceted manner.

Table VI-2. Selected Alcohol-Related Diagnoses, Alcohol-Attributable Fractions (AAFs), and Age Ranges Included in the Calculation of AAFs

ICD-9-CM
Code
Diagnosis
AAF
Age
 
Alcohol-Related Diagnoses With AAFs Equal to 1
  
303
Alcohol dependence syndrome
1.0015 and older
305.0
Nondependent abuse of alcohol 1.0015 and older
425.5
Alcoholic cardiomyopathy
1.0015 and older
571.0Alcoholic fatty liver 1.0015 and older
571.1Acute alcoholic hepatitis1.0015 and older
571.2Alcoholic cirrhosis of liver1.0015 and older

 

 

Alcohol-Related Diseases With AAFs <1
  
011, 012
Pulmonary and other respiratory tuberculosis0.2535 and older
140-149
Malignant neoplasm of lip, oral cavity, and pharynx
0.5035 and older
150Malignant neoplasm of esophagus0.7535 and older
151
Malignant neoplasm of stomach0.20 35 and older
155
Malignant neoplasm of liver and intrahepatic bile ducts
0.1535 and older
571.5
Cirrhosis of liver without mention of alcohol

 

0.5035 and older
 
Alcohol-Related Injuries With AAFs <1
  
E810-E825
Motor vehicle traffic and nontraffic accidents
0.42All
E960-E969
Homicide and injury purposely inflicted by other

persons

0.4615 and older

Source: Adapted from: McDonald AJ 3rd, et al. US emergency department visits for alcohol-related diseases and injuries between 1992 and 2000. Arch Intern Med 164(5):531-7, 2004

C.1. Metabolism and Organ Injury

The routes by which alcohol causes organ pathologies continues to be of great interest as an understanding of these mechanisms is key to the development of both preventive and treatment approaches to these disorders that, as noted above, exact high morbidity and mortality in the U.S. population. Alcohol may cause tissue and organ injury via many mechanisms, and researchers in recent years have gained an increased understanding of several factors contributing to the development of these conditions. But a complete understanding of the mechanisms underlying these diseases, whether they are common across multiple organs, or specific to only one organ, requires exploration and identification of new knowledge.

Alcohol by itself, or through its metabolites, can elicit various pathologic conditions. Alcohol also may serve to perturb other metabolic pathways thereby changing the relative concentrations of other biological intermediates in eliciting the development a particular pathologic condition. For example, alcohol may alter pathways involved in the biosynthesis of methyl donors, or in generating reactive oxygen species or in depleting antioxidants all of which may be detrimental to cells, tissues and organs.

One of the direct routes by which the alcohol molecule contributes to organ pathologies is through its actions on the intestinal mucosa, an action that increases the permeability of the intestine to the bacterial endotoxin lipopolysaccharides (LPS) into the circulatory system. LPS is an important factor in the development of alcoholic hepatitis, which in turn may contribute to the development of other liver pathologies such as liver cirrhosis and cancer.

The alcohol metabolite acetaldehyde also may serve as a potential source of organ cell toxicities. Acetaldehyde is the first metabolic intermediate in the oxidative metabolism of alcohol. Acetaldehyde can form adducts with various proteins and other molecules potentially disrupting their normal physiological function. Individuals with specific variants of the two major enzymes in alcohol metabolism, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) achieve elevated levels of acetaldehyde when they consume alcohol. These ADH variants are the alleles ADH1B*2 or ADH1B*3, and the ALDH variant is the allele ALDH2*2. The consequence of possessing one of these enzyme variants, especially the ALDH variant, can produce a dysphoric state that includes facial flushing and nausea. Experiencing these unpleasant reactions can limit the desire to consume alcohol. It has been shown that Individuals with the ALDH2*2 variant have a greatly reduced risk for alcohol dependence. Most likely related to the decreased drinking, individuals with the ALDH2*2 variant have over a 70% reduction in alcoholic cirrhosis, presumably due greatly reduced frequency and quantity of alcohol consumption. While individuals possessing both the ADH and ALDH variants are at lower risk alcohol dependence (alcoholism), when they do drink, they are likely at higher risk for tissue and organ pathology from acetaldehyde.

Another route to alcohol-induced tissue injury is through the generation of reactive oxygen species (ROS). As presented in an earlier section, the cytochrome P450s, as well as the mitochondrial oxidative chain are capable of generating ROS as a consequence of alcohol metabolism. When sufficient levels of ROS are generated they can deplete the cells reserve of antioxidants, among which is glutathione, thereby increasing the likelihood of oxidative injury.

Elevated levels of ROS have been shown to lead to the peroxidation of lipids, proteins, and DNA. The products of lipid peroxidation include two aldehydes, malonedialdehyde (MDA) and 4-hydroxynonenal (HNE). As is the case with acetaldehyde, both of these aldehydes can form adducts with proteins. As well, acetaldehyde and MDA can react with proteins in a synergistic manner to generate a stable adduct, MDA-acetaldehyde-protein adduct (MAA). MAA has been demonstrated to be immunogenic and it can induce inflammation and autoimmune reactions in various systems, including the circulatory system, and alter neuroendocrine functioning.

Another consequence of the elevated levels of ROS is the potential for mitochondrial damage which affects cell survival by inducing programmed cell death (apoptosis). ROS may further cause organ injury through the alteration of gene expression. ROS are capable of stimulating transcription factors such as NF6B and AP-1, which in turn increases the genetic transcription of inflammatory cytokines (part of the disruption of mitochondrial signaling pathways) leading to tissue damage.

Fatty acid ethyl esters (FAEE) are another class of metabolic products arising from alcohol metabolism, in this case via a non-oxidative esterification between fatty acids and alcohol. FAEEs may accumulate in significant concentrations in some organs, including the pancreas where they may contribute in the development of acute and chronic alcoholic pancreatitis.

Alcohol use may also lead to the development of organ pathologies by altering the mechanisms through which normal epigenetic regulation occurs (see Figure VI-1). For example, in a rat model alcohol has been shown to cause an increase in the acetylation of one particular histone protein, H3, in a site-specific manner. The consequence is an increase in transcription of a number of genes, including the gene for the rat class I ADH enzyme. This research further showed that acetate, an alcohol metabolite, was responsible for this effect by acting upon the enzyme histone aceteyltranferase (HAT).

Figure VI-1. Epigenetic Implications for Alcohol Metabolism
Selected Alcohol-Related Diagnoses, Alcohol-Attributable Fractions (AAFs), and Age Ranges Included in the Calculation of AAFs

Source: Garro et al ACER 15:395, 1991; Lu et al., Am J Physiol Gastrointest Liver Physiol 279:G178, 2000; Lu and Mato, Alcohol 35:227, 2005; Mason and Choi Alcohol 35:235, 2005.

In another example, alcohol, at high intoxicating doses, has also been demonstrated to bring about a significant reduction in tissue levels of the metabolite, S-adenosylmethionine, required for the methylation of both histones and DNA. By inhibiting the biosynthesis of methionine at the level of the enzyme methionine synthase (MS) (Figure VI-1) the synthesis of the methyl donor S-adenosyl methionine will be impaired, and in turn the methylation of histones and DNA. In this manner, alcohol has the potential to cause significant disruption in gene expression altering many biological processes that may result in various disease states. Decreased DNA methylation has been linked to tumor formation, although it is not known whether this is the route by which alcohol increases the risk for the development of cancer in such organs as the liver, throat, larynx, and esophagus.

As noted in an earlier chapter, the oxidation of alcohol to acetaldehyde and subsequently to acetate is accomplished by the reduction of the co-factor nicotinamide adenine dinucleotide (NAD+) to its reduced form, NADH. This changing in the oxido-reductive (redox) state itself has the potential to cause metabolic changes, including those that involve gene expression. One example of this has been demonstrated in yeast and rat studies of caloric restriction. Caloric restriction increases NAD+ relative to NADH. The yeast enzyme histone deacetylase, Sir2, and the rat version of this enzyme, SIRT1, respond to this increase in NAD+ by significantly increasing their catalytic activity. The function of histone deacetylase is to remove acetyl moieties from specific sites on histone proteins. In turn, the removal of the acetyl moieties silences selected genes in the region of the affected histone proteins. Among the genes silenced are those that code for enzymes involved in the deposition of lipids into fat cells, a desired effect during a period of starvation. While the shift in the NAD+/NADH ratio resulting from alcohol metabolism, which would be in the opposite direction to that arising from calorie restriction, has yet to be shown to have an effect on gene expression mechanisms, the possibility of observing this phenomenon is worthy of pursuit.

 

C.2. Organ Disease

Many of the major systems and organs of the body may develop a disease state from heavy and long-term use of alcohol. Several of these disorders are presented in the section on epidemiology (above). While advances in our understanding of all of the diseases are not discussed here, particular note is made of research findings on alcoholic liver disease because of its identification as the leading cause of death from alcohol.

Liver Damage. The multiple disorders of the liver that can arise from alcohol use are collectively referred to as alcoholic liver disease. Among these is fatty liver, a condition once considered to be benign. Other alcohol-derived diseases in the liver include an inflammatory disease, alcoholic hepatitis, and alcoholic cirrhosis, a disease characterized by marked scarring of the liver. Other agents, such as a variety of other chemicals and various bacterial and viral agents may also bring about liver disease, and alcohol has generally been considered to accelerate the progress of liver disease arising from viral agents such as hepatitis C, one of the other major causes of liver disease in the U.S. However, while individuals with hepatitis C who drink clearly have increased risk for progression to cirrhosis, whether there is an interactive as compared to a simple addition effect of the alcohol exposure, or whether there is a threshold dose above which alcohol accelerates viral liver diseases remains to be determined.

Alcohol-induced liver disease (ALD) occurs in only about 15-20% of heavy alcohol consumers suggesting that genetic factors may contribute to this process. Recent research has suggested that such genetic factors as the presence of mutant c2 allele of CYP2E1 may increase the risk of alcoholic liver disease.

C.3. Genetic Variants and Alcohol Pathology

Genetic factors have also been considered to underlie the risk for other alcohol-related disorders, beyond alcohol dependence itself which was discussed previously (Chapter V. Young Adult). Research has suggested that individuals with the ADH1C*1 allele have an increased risk to develop breast cancer from moderate amounts of alcohol. However, a putative mechanism to explain this association has not been established. It is also possible the genetic risk factor is not ADH1C*1 but ADH1B*2, a variant of ADH which is in linkage disequilibrium with ADH1C*1. Also, several polymorphisms of CYP2E1 have been identified and a few preliminary studies have been undertaken to determine their effect on alcohol metabolism and tissue damage. In one study, an association between the m2/m2 CYP1A1 genotype and alcoholic liver cirrhosis was found. Another study found a relationship involving glutathione S-transferase where the Val/Val GSTP1 variant was associated with chronic pancreatitis.

C.4. The Effects of Moderate Alcohol

In addition to the development of pathologic conditions, many years of epidemiological studies have produced findings to suggest that moderate alcohol use (defined as no more than one drink per day for women and two drinks/day for men) may afford a degree of protection from a number of disease conditions including coronary artery disease (CAD), type 2 diabetes, dementia, and ischemic stroke. Recently, the results of many such studies in the literature have been re-analyzed by several groups of researchers in a meta-analysis examining the effects of moderate alcohol consumption and total mortality in both men and women. It appears that J-shaped relationship between moderate alcohol consumption and total mortality is similar for both sexes, and that low to moderate levels of alcohol consumption do confer some protection for mortality. Although some mechanisms of action for this epidemiological finding have been studied, more basic research offers the potential to confirm these initial findings and more fully understand the means by which protection is afforded. Such findings could guide the development of pharmaceutical approaches for the prevention and treatment of these disorders.

Of all of the disorders that may benefit from moderate alcohol consumption, CAD has been the most studied. Mechanisms that appear to underlie alcohol-induced cardioprotection include changes in serum lipids, blood clotting proteins, platelets, anti-oxidant polyphenols and inflammatory cytokines. In addition, several reports suggest that moderate alcohol consumption lowers systemic markers of inflammation, e.g., C-Reactive Protein (CRP) associated with increased risk for CHD. Also, exposure of the myocardium to a moderate alcohol dose before an ischemic insult resulted in up to an 80% reduction in cardiac damage. Enhanced recovery appears to be is associated with sustained activation of e-Protein Kinase C (PKC).

One potential mechanism underlying alcohol-induced reduction of risk for Type II diabetes is an increase in insulin sensitivity. Formation of advanced glycation end products (AGE's) and their binding to vascular wall components contributes to atherogenesis. The anti-atherogenic effect of moderate alcohol consumption may be linked to acetaldehyde, which can react with nucleophilic precursors of AGE's to prevent AGE formation and lipoprotein oxidation.

Some research to date on the mechanisms underlying alcohol-induced reduction of risk for age-related dementia have focused on constituents of alcoholic beverages including wine such as polyphenols, tannins, and anthocyanin pigments that have antioxidant and anti-inflammatory properties. In degenerative diseases of the brain, alterations in consciousness are associated with regional deficits in the cholinergic system. Moderate alcohol consumption has been shown to enhance the release of acetylcholine in the hippocampus which may underlie its neuroprotective effect.

A complete understanding of the biological mechanisms underlying the protective or beneficial effect of alcohol consumption may improve our understanding of the molecular targets that could lead to development of therapies for coronary artery disease, dementia and diabetes.

C.5. Alcohol and Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDs)

The acquired immunodeficiency syndrome (AIDS) was first reported in the United States in 1981 and has since become a major worldwide epidemic. Caused by the human immunodeficiency virus (HIV), AIDS has killed more than 500,000 people in the United States, and as many as 950,000 people in the U.S. may be infected with HIV. Between 40,000 and 60,000 new HIV infections occur each year in this country.

The epidemic is growing most rapidly among minority populations and is a leading killer of African-American males ages 25 to 44. According to the Centers for Disease Control and Prevention (CDC), AIDS affects nearly seven times more African Americans and three times more Hispanics than whites. People with HIV/AIDS are susceptible to opportunistic infections caused by viruses or bacteria that usually do not make healthy people sick. HIV-infected individuals may also suffer from depression, dementia, various psychiatric conditions, and early neuropathology, manifested as impaired cognition and motor function, and poor executive function.

Studies estimate that more than 80 percent of HIV-infected individuals drink alcohol and that between 30 and 60 percent of people with HIV also have alcohol use disorders. Research also indicates that chronic alcohol consumption facilitates HIV infection in people who have been exposed to the virus, and accelerates the disease process and death of HIV-infected people who progress to AIDS. The reasons for these effects are unclear, but may involve basic biological actions of alcohol and its metabolites on the virus and its tissue target. Alcohol may also interfere with the metabolism of anti-HIV medications, an effect that could account for the increased frequency of adverse medical events from treatment with antiretroviral regimens among HIV-infected individuals who drink alcohol.

Social factors influence the interaction between HIV and chronic alcohol consumption and may affect the progression to AIDS. For example, people with alcohol use disorders are less likely to be tested for HIV. Such individuals who do get tested and are found to be HIV-positive are less likely to seek treatment, and less compliant with prescribed treatments for HIV infection or related diseases, than individuals without alcohol use disorders. Excessive alcohol consumption also is closely associated with HIV/AIDS risk behaviors such as unprotected sexual intercourse and intravenous experimental drug use. Although HIV is most commonly diagnosed at midlife, HIV infection usually is contracted earlier in life, typically during the young adult stage, a period often characterized by heavy alcohol consumption or binge drinking and increased prevalence of high risk behaviors associated with HIV transmission.

Effective treatment for both alcohol abuse and HIV/AIDS leads to reductions in viral load, viral mutation, and subsequent infectivity. The complex interactions between alcohol and HIV/AIDS, as well as the broad range of co-morbidities experienced by HIV-infected individuals who drink alcohol provides a rationale for longitudinal clinical studies aimed at advancing our understanding of these complex issues.

D. Treatment: Mechanisms of Behavior Change

Most individuals who seek alcoholism treatment do so during the midlife period. Currently available treatments, which include behavioral therapies and those that employ behavioral treatment with newly available medications, help many such individuals successfully recover from alcohol dependence. With minor exceptions, therapeutic approaches using different models yield similar results, and there is only minimal interaction with a wide variety of demographic and clinical patient characteristics.

 

Recommendations of the NIAAA Extramural Advisory Board (EAB) 'Developing an NIAAA Plan for HIV-related Biomedical Research'

  • Focus on key mechanistic targets for ethanol and HIV-induced injury to identify, measure, and prevent additive and interactive harmful effects at the cellular and organ systems level.
  • Examine the pharmaco-kinetic and -dynamic effects of alcohol on current and emerging pharmacotherapies for the treatment of AIDS and alcohol use disorders.
  • Characterize unique aspects of alcohol/HIV interactions among women, children, adolescents and older adults in domestic and international settings and how these are moderated by racial, ethnic, and environmental factors.
  • Examine impact of alcohol on viral indices, mucosal barriers, blood brain barrier, and immune responses and their impact on susceptibility, progression, and transmission of HIV.
  • Develop cellular, systems-level, and animal models to study mechanisms underlying alcohol/HIV interactions, and to identify effective approaches to translating findings from animal models to human models of alcohol/HIV interactions in the etiology and pathogenesis of AIDS.
  • Study the effects of longitudinal drinking patterns on HIV disease course, co-morbid disease burden, development, and neurocognitive function.
  • Determine mechanisms of alcohol-related immune dysregulation in HIV with and without co-infection (e.g., TB, HCV, etc.) and the impact of other co-morbidities.

Detailed information regarding these EAB recommendations can be found at: http://www.niaaa.nih.gov/ResearchInformation/ExtramuralResearch/AdvisoryCouncil/

 

Just as some young adults recover from alcoholism without the benefit of treatment, some individuals' transition away from alcoholism during midlife without the help of any specialty alcohol treatment, a phenomenon sometimes referred to as "aging out." Indeed, the NESARC and other studies reveal that a large majority of heavy drinkers (including those with dependence) reduce or stop drinking without seeking help in a specialty treatment program. However, many other individuals either do not experience this aging out phenomenon at all, or achieve multiple episodes of short-term success from their alcohol use disorder followed by relapse back into alcohol dependence.

People who resolve heavy drinking and its related problems without specialized treatment differ systematically from those who do. Recovery outside of treatment is more likely in those with fewer symptoms of dependence, less co-morbid psychiatric disorders, less pressure to quit drinking, and more social capital. This group of individuals forms a unique population for further study. Although these individuals resolve their alcohol use disorder, a more comprehensive understanding of how the natural recovery occurs would provide the research community with the information required to develop interventions targeting those individuals who would not normally seek treatments. One of the goals of this area of research would be to reduce the amount of time these individuals must endure the current and future range of consequences related to their alcohol use disorder before they age out or recover naturally. Progress has been made to delineate trajectories and their statistical predictors among young people, where much non-treatment change takes place.

Recommendations from NIAAA Extramural Advisory Board (EAB) for 'Mechanisms of Behavior Change'

  • Develop consortia of investigators using existing studies or data sets to test a series of common questions. These questions will use a transdisciplinary approach that integrates neuroscientific, computational, and behavioral-social sciences.
  • Promote funding mechanisms that allow time for adapting and/or developing conceptual approaches and measures for assessing behavioral change.
  • Emphasize the development of innovative and exploratory research, recognizing the high risk nature of this type of work. Develop and support longitudinal studies of the natural history of behavioral change in drinking behavior.

More detail on the recommendations made by the NIAAA EAB can be found at: http://www.niaaa.nih.gov/ResearchInformation/ExtramuralResearch/AdvisoryCouncil/

 

Still, a better understanding of the characteristics, mediators, and environmental factors that motivate individuals to try to change their drinking behavior, either on their own or through professional alcoholism treatment, will greatly aid the search for improved prevention and treatment strategies. If specific psychotherapy techniques are not primary change agents, how does change occur? Even if "common factors" such as therapist empathy, expectancy, therapist allegiance to the model, and the therapeutic alliance are change agents, how, exactly, do they work? In addition, improving the efficacy of alcoholism treatment will require greater knowledge of the factors and mediators that underlie a transition from alcohol dependence in those individuals who are successful in recovering, in both the absence and presence of formal alcoholism treatment. Insofar as it appears that the change processes begin well before treatment entry, it may be that treatment is more a result of change rather than a cause of it. Even if that were the case, though, treatment could still have important effects such as prevention of relapse, or more rapid or profound or more gratifying change.

Historically, research on professional psychosocial interventions focused first on development of theoretical frameworks to explain change and to direct intervention efforts. Examples of such frameworks include cognitive-behavioral, twelve-step, and motivational enhancement. Subsequent research in this area included studies to refine the internal validity of studies of these frameworks using therapy manuals, training, and monitoring; development and use of well-validated and reliable instruments; and improved research designs such as randomized controlled trials. The results were unexpected: treatments with very different conceptual frameworks and intervention techniques have approximately equivalent (and reasonably good) outcomes (e.g., abstinence or significantly decreased drinking and consequences). Furthermore, relatively brief, non-intensive treatments yield outcomes as good as more intensive treatments. These results suggest that non-specific factors such as a decision to seek help, installation of hope, empathy and the therapeutic alliance may be more important that specific factors hypothesized by treatment models. An alternative explanation is that the mechanisms are specific to each technique but they lead to a common outcome. One reason that the two alternatives have not been differentiated is that research to date has primarily focused on simple efficacy comparisons, and therefore has been silent on the question of what the mediators and moderators of change in these treatments actually are.

E. Treatment: Medications Development

While for many years, alcoholism treatment approaches relied almost exclusively on behavioral therapy, efforts to develop medications for alcohol use disorders have expanded rapidly in recent years. Three agents -- disulfiram, naltrexone, and acamprosate -- are now approved for use in the United States and many other countries. As is the case with medications for other chronic diseases, these medications have been found to be highly effective with some patients but others have failed to respond to them. New medications, providing effective therapy to a broader spectrum of alcoholic individuals, would be of value for the treatment of alcohol dependence. Research findings revealing that drinking and alcohol-seeking behavior are influenced by multiple neurotransmitter systems, neuromodulators, hormones, and intracellular networks provides evidence that there are a number of potential target sites for which new pharmaceuticals may be developed. Potential target sites include neurotransmitter systems related to opioids, serotonin, dopamine, glutamate, gamma-aminobutyric acid (GABA), cannabinoids, the hypothalamic-pituitary-adrenal (HPA) axis, adenosine, neuropeptide systems (for example, neuropeptide Y, corticotrophin releasing factor), signal transduction pathways (such as, protein kinase A and protein kinase C); and gene transcription factors (delta fos B and cAMP response element-binding protein [CREB]). Indeed, many such agents are under test as shown in Table VI-3. Among these agents several promising compounds are currently being considered as candidates (baclofen, rimonabant, and memantine) for evaluation to determine their safety and efficacy in the treatment of alcohol use disorders and it is likely that additional agents will be identified as medications development efforts for alcoholism proceed.
Table VI-3. NIAAA Medication Development Lead Compounds

Medication under development

Mechanism

Pre

Cln

Ph1

Ph2

Ph3

Naltrexone depot formulation (Vivitrex®) Alkermes)

Opiate antagonist

X

Topiramate (Topamax™ Ortho-McNeil)

Facilitates GABA and inhibits glutamate activities

X

X

Gabapentin (Neurontin™ Pfizer)

Facilitates GABA and inhibits glutamate activities

X

Ondansetron(Zofran™ GSK)

5-HT3 antagonist

X

Baclofen (FDA approved)

GABAB agonist

X

rimonabant

(Acomplia™ Sanofi-Synthelabo)

Cannabinoid CB1 antagonist

X

Memantine (Namenda™ Forest Laboratories)

glutamate NMDA antagonist

X

antalarmin

CRF1 antagonist

X

CRF1 antagonist

CRF1 antagonist

X

Kudzu extract

Unknown

X

Diphenylureido compound, DCUKA

glutamate NMDA antagonist, sodium channel blocker

X

Aripiprazole

Dopamine partial agonist

X

NK1 antagonist

Neurkinin1 receptor antagonist

X

Nociceptin agonist

NOP agonist

X

N,N'-bis-(3-aminopropyl) cyclohexane-1,4-diamine (DCD)

Glutamate NMDA antagonist

X

2-Methyl-6-(phenylethynyl)-pyridine (MPEP)

mGluR5 antagonist

X

NPY agonists/antagonists

NPY agonists/antagonists

X

CRF2 agonists

CRF2 agonists

X

Adenosine A2 antagonists

Adenosine A2 antagonists

X

betaCCt

GABAA 1 mixed agonist/antagonist

X

RY 023

GABAA 5 inverse agonist

X

 

The development of new medications for alcoholism is greatly aided through the use of animal models for the screening of new agents that can alter attributes associated with alcohol dependence. Several laboratory paradigms which model facets of alcoholism are now used to study the behavioral effects of alcohol in mice, rats and monkeys. These include:

Therefore, while it is now possible to model some attributes of dependence, craving, lapse, and relapse using a variety of current animal laboratory paradigms, new models that more closely model the endophenotypes and intermediate phenotypes (for definitions see Table I-10) involved in the development and expression of alcoholism would greatly benefit medication development efforts. For example, the endophenotype of neural disinhibition may be modeled in different animal models and prove useful as a tool for medication development research.

Another aid in the search for new medications is through human laboratory testing. Testing of model therapeutics, in a human laboratory environment with a relatively small subject population carefully selected for their targeted drinking behavior can provide a significant savings in the time and cost associated with clinical trials for the development of new medications. These efforts are undertaken after animal pre-clinical screening. Currently, there is no consensus on the best way to evaluate drugs to treat alcoholism in the human laboratory environment, although two models have been used: alcohol self-administration and relief from the symptoms of alcohol protracted abstinence. The continued study of these laboratory animal models, and the development of new models is timely and required for rapid progress to be made in the screening of targeted compounds shown to offer promise from animal studies.

The identification of new biomarkers to provide an early indication of treatment success would be a great asset in medications development. During the past years, efforts have been made to develop and characterize new as well as traditional biomarkers of alcohol consumption and alcohol-induced tissue injury. Traditional biomarkers of alcohol consumption include gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and corpuscular volume (MCV). Newer markers include carbohydrate-deficient transferrin (CDT), 5-hydroxytryptophol (5-HTOL), a serotonin metabolite, and ethyl glucuronide (EtG), a metabolite of alcohol.

In addition to biomarkers of alcohol consumption, biomarkers of alcohol-induced tissue injury are also of importance. Such potential markers for alcoholic liver disease include alpha-smooth muscle actin (SMA), fibronectin, collagen type I, serum hyaluronate, matrix metalloproteinase (MMP)-2, and MMP-9.

However, current biomarkers, for the most part, lack specificity or sensitivity, or have a very short half-life. Due to the limitations of these biomarkers, it is vital to discover new biomarkers that are unique to alcohol consumption and/or alcohol-related diseases. Recent advances in high-throughput technologies for proteomics, genomics, and metabolomics have been successfully used for studying complex biological problems and show promise for the identification of individual biomarkers and unique signatures. These high-throughput technologies have created new exciting opportunities for discovering and developing novel biomarkers that may be useful for alcohol-use disorders.

Another important direction for medications development research lies in pharmacogenetic research, that is, the identification of genetic subtypes of alcohol dependence that respond to specific pharmacologic agents. Research in recent years has discovered specific genetic variants that may contribute to the risk for alcoholism, and which may define specific sub-sets of alcohol dependent individuals who respond to specific therapeutic agent. Among the genetic variants are the GABAA receptor genes GABRA2 and GABRG3 that have recently been associated with alcoholism. Other promising sites include the short versus the long allele of the serotonin transporter, the presence or absence of the A1 allele of the dopamine D2 receptor gene, catechol-O-methyltransferase (COMT) Val158Met allele, and the NPY gene variant Leu7Pro. Also included here, as discussed in the context of protection versus susceptibility for alcoholism, are the polymorphisms in the alcohol dehydrogenase gene ADH1B and the aldehyde dehydrogenase gene ALDH2. Consideration of an individual patient’s unique genetic profile and phenotypic characteristics may help in the future for selecting the most effective anti-alcohol medication. Although research is in early stages, some advances have been made. A polymorphism in the gene that codes the opioid mu receptor (A118G, which causes an Asn40Asp substitution in the protein) has recently been associated with the response to naltrexone in alcohol dependent patients and to a family history of alcoholism, alcohol intoxication, and alcohol-induced stimulation and sedation. In a preliminary study, alcoholic patients treated with the drug olanzapine who possess the dopamine DRD4 L allele (7 or longer repeat allele of the tandem repeats [VNTR]) experienced reduced craving for alcohol, while olanzapine did not reduce craving in those with the DRD4 S allele.

Progress has also been made with respect to defining new medication targets for organ pathologies. In particular, cytokines, reactive oxygen species (ROS), and other primary factors in the onset and progression of alcoholic liver disease may prove fruitful as medication targets. For example, it has been found that the severity of alcohol-induced liver injury in rats could be reduced through the administration of antibodies against tumor necrosis factor α (TNF-α), a molecule that promotes inflammation. Antioxidants such as Vitamin E, glutathione, or its methyl donor, S-adenosyl-L-methionine (SAMe) also have shown potential for treating alcoholic liver disease. These compounds can quickly inactivate ROS, by-products of alcohol metabolism that can damage the liver. Research suggests that cannabinoid CB1 antagonists and CB2 agonists may be a potential therapeutic target for alcohol treatment given their close association with the reward centers of the brain (nucleus accumbens) and their modification by ethanol intake in animal studies. Furthermore, metformin, an insulin-sensitizing agent, also warrants further study as a potential medication for alcoholic liver disease.

 

F. Opportunities
Metabolism and Organ Injury

Alcohol and HIV/AIDS

Treatment and Behavioral Change

Medications Development

Increase the number of medications available for the treatment of alcoholism to reach a broader spectrum of individuals with alcoholism. To accomplish this goal, the following initiatives are currently timely and feasible:
G. Outreach
 
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CHAPTER VII. Senior Adult

A. Background

Aging is associated with a variety of changes that place senior adults at special risk for alcohol-related health problems. As people live longer, the absolute number of senior adults who continue to drink as they age will increase. Since the percentage of aging individuals in the general population is steadily increasing, the number of senior adults with problem drinking habits will become a national healthcare issue. Senior adults are known to differ in their physiological and behavioral responses to alcohol in a variety of social contexts, and their ability to respond to alcohol tolerance is greatly altered during the senior years. Drinking can aggravate a variety of pathological conditions in the senior adult including stroke, hypertension, neurodegeneration, memory loss, mood disorders, and cognitive or emotional dysfunction. On the other hand, moderate drinking in the senior population has been shown to have some effect on reducing the risk of death; both women and men consuming alcohol daily had a 15% reduction in risk of death, and the stable consumption of alcohol across the senior lifespan (measured over two decades) appeared to be a significant factor. Notwithstanding the obvious problems associated with diagnosing problem drinking in the senior adult population, including the similarities in alcohol-related and age-related manifestations, the results of studies may be influenced by the location of the subjects at the time of measurement (e.g., nursing home or assisted care facility, independent living in retirement community, hospital, primary care setting).

 

B. Epidemiology

Although senior adults drink less than other adults, their pattern of alcohol consumption has changed over time; more recent birth cohorts of seniors tend to drink more than less recent birth cohorts, which represents generational shifts in attitudes about alcohol consumption over time. Therefore, more aging individuals will be drinking more and the health related issues resulting from this fact will change the need for better surveillance of the problems faced by the future generations.

Table VII-1. Percentage of U.S. Adults 18 and Over with Past-year Alcohol Abuse or Dependence and Percentage of Those with Past-year Abuse or Dependence Who Received Alcohol Treatment, by Type of Treatment

Past-year disorder

Type of treatment

Age group

Abuse

Dependence

Any treatment

12-Step only

Other only

12-Step and other

60+

1.4 (0.1)

0.5 (0.1)

3.4 (1.3)

1.9 (1.1)

0.8 (0.6)

0.6 (0.4)

Source: Adapted from Table I-8 in the overview.

As shown in the table above (Table VII-1), only 0.5 percent of individuals over 60 met criteria for a diagnosis of alcohol dependence during the previous year. Only 1.4 percent met a diagnosis of alcohol abuse. Despite this, only 3.4 percent of those meeting a diagnosis of either alcohol dependence or alcohol abuse had, at some point in their lives, treatment for their alcohol-use disorder.

In a large sample of seniors aged 65-103 years in primary care, heavy alcohol consumption and binge drinking were associated with depression, anxiety and perceived poor health compared with moderate drinkers, and in another study, moderate alcohol consumption was associated with better cognitive health and subjective feelings of well-being than non-drinkers. In addition, moderate alcohol consumption was related to lower Medicare costs in patients with cardiovascular disease (CVD) than in non-drinking patients with CVD.

Longitudinal studies indicate the majority of those individuals who drink heavily as seniors were also heavy consumers over the course of their adult years before entering the senior adult years. Consumption of alcohol has declined more slowly among the more recent cohorts of older individuals as subsequent generations of senior adults are influenced by generational attitudes towards drinking. This has significant implications for healthcare of future senior adult populations. An important distinction is made between individuals with an early onset versus late onset of problem drinking: those with a late onset (the majority are female) have a better chance at recovery and fewer alcohol-health related problems than those with an early onset of problem drinking, although little research on this specific topic has been performed. However, alcohol misuse in the senior adult population remains an important public health issue since older individuals are more likely to have additional health problems that may confound accurate diagnoses of wholly organic versus wholly alcohol problems.

One of the major issues with respect to estimating the prevalence of alcohol abuse in senior adults involves survey location, e.g., estimates are lowest from community-based surveys (those that sample from senior adults living in independent settings), increased from health care settings (hospital admissions from emergency room and psychiatric wards), and the highest estimates were derived from studies within nursing and critical care facilities, and the diagnostic criteria with which senior adults are compared for the purpose of diagnosis (many of the criteria are not relevant for the senior adult with drinking problems).

C. Etiology

The etiology of problem drinking by older persons is not well studied. Obviously, senior adults differ from non-senior adults in physiology, biology and social aspects, all of which may contribute to higher alcohol consumption on average in the senior adults. In terms of biological effects, senior adults have a smaller body mass and lower water content than non-senior adults, thus the blood alcohol concentration attained for like-amounts of alcohol consumed will differ between these groups of individuals independent of their inherent metabolism. Senior adults are more likely to have intrinsic problems with health issues related to blood pressure, sleep patterns and bone metabolism, for example, which may prompt an increase in alcohol consumption to offset the perceived effects of such medical conditions. Senior adults take more medications than non-senior adults, therefore causing a potential reduction in the effectiveness of medications taken to alleviate specific medical conditions or a significant interaction between prescription drugs and alcohol resulting in additional potential for harmful side effects of either drug on the individual.

There are various social factors that may result in increased alcohol consumption in senior adults, such as loss of a spouse, lack of or reduced family support, and the availability of disposable income to engage in drinking. Furthermore, the period of retirement may be a risk factor in the development of increased alcohol consumption since senior adults have more unstructured free time and no longer have job-related ramifications of heavy alcohol consumption. Individuals in any age range may misinterpret the information regarding the benefits of alcohol consumption on general health (including misinterpretation of amount and frequency that may produce the benefit). For senior adults, the consequences of inappropriately weighing the relative risk versus benefit of alcohol consumption for their age group may have particular negative consequences with regard to their personal medical conditions.

D. Treatment and Prevention

There is some evidence that senior adults will respond positively to treatments especially if they are treated within groups consisting of similar-aged individuals. Senior adults with late onset problem drinking (more typical of female than male) and shorter history of problem drinking tend to respond more positively to treatment efforts than those with early onset problem drinking. The most efficacious therapies seem to involve cognitive-behavioral therapy and group and family therapy, which tend to involve familial support mechanisms that may have been an exacerbating factor for the increase in late-life alcohol abuse. There is some indication that medications developed to promote abstinence may not work as well in senior adults given that the mechanism of benefit may be altered due to age-related issues (more so than to alcohol-related issues), although this area is not well studied in the clinical population.

Similarly, based on the current literature, the most beneficial prevention of senior adult alcohol abuse is education, since some reports indicate that lack of knowledge about alcohol abuse rather than a disregard for the information was at the root of some problems associated with relapse in senior adult problem drinkers. Since there is no definitive phenotype for the senior adult problem drinker, the development of current prevention efforts must be geared towards generalized personality or situational characteristics that have led to problem drinking in like-age groups of individuals.

E. Opportunities

Although the fundamental processes responsible for normal chronological aging clearly can influence individuals’ responses to alcohol, the basic biological mechanisms underlying this relationship have remained largely unexplored. Recent studies have yielded exciting new information about how chronological aging affects brain function, cardiovascular function, endocrine function, and immune function. Likewise, there has been dramatic progress in alcohol research from genetic to behavioral and cognitive levels. These advances, together with recently developed technologies and experimental models, provide important new opportunities to examine how mechanisms affected by alcohol exposure and aging interact with one another. Some of these mechanisms may mediate altered physiological functions in different tissues, while others may participate in degenerative processes leading to tissue damage.

F. Outreach

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