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Statement on Diabetes by Phillip Gorden, M.D.
Director, National Institute of Diabetes and Digestive and Kidney Diseases
National Institutes of Health
U.S. Department of Health and Human Services

Mr. Chairman, I am Phillip Gorden, the Director of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), which has lead responsibility for diabetes research at the National Institutes of Health (NIH), within the Department of Health and Human Services (DHHS).

I appreciate the opportunity to testify before the Congressional Hispanic Caucus about NIH research to understand, treat, and prevent diabetes.

In both human and economic terms, diabetes is an extremely costly disease. It affects an estimated 16 million Americans, including both genders, the young and the old, all races and ethnic groups, the rich and the poor. According to the American Diabetes Association, diabetes and its complications of the eye, kidney, nervous system, and heart cost an estimated $98 billion annually. Consistent with the focus of today's hearing, I will address my testimony toward diabetes in the Hispanic community.

Diabetes is a disease in which the body does not produce or properly use insulin, a hormone that is needed to convert sugar, starches, and other food into energy essential for daily life. The cause or causes of diabetes are unknown in most instances, although both genetic and environmental factors appear to play a role. Type 2 diabetes, the form most commonly seen in the Hispanic community, occurs at a rate approximately twice that in the non-Hispanic Caucasian population. Formerly known as non-insulin-dependent diabetes mellitus or adult-onset diabetes, type 2 diabetes is the most common form of the disease, accounting for 90 to 95 percent of diabetes. Type 1 diabetes, formerly known as insulin-dependent diabetes mellitus or juvenile-onset diabetes, most often occurs in children, and accounts for 5 to 10 percent of all diabetes in the United States .

Diabetes in Hispanics is a serious health challenge because of the increased prevalence, the greater number of risk factors, and the greater incidence of complications. In early 1999, data released by the Centers for Disease Control and Prevention (CDC) indicated that six percent of Hispanic adults in the United States and Puerto Rico have been diagnosed with diabetes--twice the rate of Caucasian Americans--while another six percent have undiagnosed diabetes. This is the first report of diabetes prevalence among all Hispanics in the United States and Puerto Rico. Most previous studies that have focused on the Hispanic community have been conducted among Mexican Americans and have found that approximately one out of every ten Mexican Americans aged twenty years and older has diabetes.

The prevalence of diabetes among Hispanic adults increases with age and varies according to geographic location. Hispanics in Puerto Rico and the West/Southwest are more likely to have diabetes than Hispanics in the rest of the nation. Diabetes is two to three times more common in Mexican American and Puerto Rican adults than in non-Hispanic Caucasians. One in every four Mexican Americans and Puerto Ricans aged 45 or older has diabetes. The prevalence of diabetes in Cuban Americans is lower, but still higher than that in non-Hispanic Caucasians. One in every six Cuban Americans over the age of 45 has diabetes.

The frequency of diabetes in Hispanic American adults is influenced by the same risk factors that are associated with type 2 diabetes in other populations--age, obesity, and genetics. Recent reports indicate an increase in the prevalence of type 2 diabetes among Mexican American youth, especially among those who are overweight. Although Mexican Americans have higher rates of kidney disease, eye disease, and peripheral vascular disease due to diabetes, they have a decreased rate of heart attacks.

HIGHLIGHTS OF NIH-WIDE RESEARCH EFFORTS AND STRATEGIES

I would like to emphasize several points that are central to present and future efforts to prevent and treat diabetes effectively. The many institutes and centers of the NIH have a broad and multi-faceted research agenda to understand, treat, prevent, and cure diabetes. Because the complications of diabetes affect so many parts of the body--the heart, the eyes, the kidneys, and the nervous system--it is an important trans-NIH research area. Efforts to reduce and eliminate health disparities among Americans are a special area of concern within the NIH. Diabetes research at the NIH is complemented by the activities of the CDC and other components of the DHHS.

We are witnessing rapid advances in the study of the patterns of inheritance of specific traits (genetics) and the development and application of global experimental approaches to assess gene function (genomics) that underlie our goal to find and eliminate the cause of many diseases, including diabetes. Major new understandings of cell communication are also critical to diabetes. Likewise, key advances in clinical research are showing how the control of blood pressure, serum cholesterol, and other lipids, as well as control of blood glucose, is important in the comprehensive care of patients with diabetes.

To identify the most promising avenues of diabetes research, the NIH has a two-step peer review process mandated by law to ensure high scientific standards among funded projects. This process begins with an assessment of scientific and technical merit by an initial review group of non-Federal scientists. Applications are then reviewed by the National Diabetes and Digestive and Kidney Diseases Advisory Council, a group of eminent scientists and lay individuals with expertise in NIDDK's areas of research, to consider program needs and the relevance of grant applications to the mission of the Institute.

In addition to the peer review system, the NIH also takes steps to guide and facilitate the development of its programs through a variety of means. In diabetes, for example, we have accelerated

and enhanced our efforts and have sought advice from a special trans-NIH workshop held in September 1997, entitled "Diabetes Mellitus: Challenges and Opportunities" -- complemented by the Strategic Plan of the Diabetes Research Working Group. We have already initiated research projects from these processes and will continue to build upon them in the future. We are also developing a new NIDDK Strategic Plan based on cross-cutting scientific themes, many of which are highly relevant to type 2 diabetes.

I am pleased to share with you today some of our most recent efforts which relate to diabetes in the Hispanic community. A number of these have been undertaken in partnership with other NIH institutes, other agencies, and voluntary organizations.

EXAMPLES OF FUNDAMENTAL RESEARCH ADVANCES

IMPORTANT TO DIABETES IN HISPANICS

The NIDDK has a major research initiative on obesity, which is a serious risk factor for type 2 diabetes. NIDDK funded the initial discovery of the obesity gene and its protein product, leptin, the major energy regulator, in a mouse model of obesity. This led to the discovery of multiple gene mutations, which control critical aspects of both eating and energy regulation. These findings have now spearheaded the discovery of at least five different genetic defects in humans that lead to obesity. Such important research advances have relevance not only to our understanding of obesity, but also to the inter-relationship of obesity and diabetes.

The National Task Force on Prevention and Treatment of Obesity was established by the NIDDK in June 1991. This task force of leading obesity researchers and clinicians is responsible for evaluating current scientifically-based information about the prevention and treatment of obesity. The Task Force also advises the Institute on important research needs and identifies concepts for future clinical studies of obesity. The NIDDK also provides support for four Obesity/Nutrition Research Centers.

The International Type 2 Diabetes Linkage Analysis Consortium originated in 1997 as a collaborative effort to map genes responsible for type 2 diabetes. This Consortium is jointly funded by the NIH and the American Diabetes Association. Currently, the Consortium includes investigators representing 23 different populations from eight countries. Locations in San Antonio and Starr County (Texas), and San Luis Valley (Colorado) include Mexican American families in the genetic linkage analysis.

Other investments in genetics and functional genomics research have led to the discovery of at least six separate genetic defects in rare forms of type 2 diabetes. Recently, a gene responsible for

type 2 diabetes has been identified in the Mexican American population from Starr County, Texas. These studies have stimulated collaborative research to penetrate the complexity of genetic abnormalities in both type 1 and type 2 diabetes. Expansion of these studies is now under way, with an emphasis on the kidney complications of diabetes. Thus, we are now making a major commitment to a large-scale study of the genetics of diabetes and the genetic susceptibility to diabetic kidney disease.

EXAMPLES OF CLINICAL TRIALS

In type 2 diabetes, the importance of maintaining close control of blood sugar levels throughout the day was conclusively demonstrated by the United Kingdom Prospective Diabetes Study (UKPDS). In addition, the UKPDS demonstrated that good blood pressure control produced a major benefit in decreasing complications of the large blood vessels. This study confirmed the findings of the NIDDK-supported Diabetes Control and Complications Trial (DCCT) in type 1 diabetes, which showed that any reduction in blood glucose reduces the risk for developing the long-term complications of the small blood vessels of the eye, kidney, and nervous system. These findings give new emphasis to the value of early treatment in type 2 diabetes. They also reinforce the importance of our Diabetes Prevention Program (DPP), a major, ongoing clinical trial designed to find out whether type 2 diabetes can be delayed or prevented. This trial is comparing the current standard regimen on diet and exercise to a more intense regimen of diet and exercise and metformin--a medication approved for the treatment of type 2 diabetes. This trial is being conducted at 27 medical centers located in Arizona, California, Colorado, the District of Columbia, Florida, Illinois, Hawaii, Indiana, Louisiana, Massachusetts, Maryland, Missouri, New Mexico, New York, Pennsylvania, Tennessee, Texas, and Washington. The DPP has completed recruitment with a total of 3,819 participants--44.5 percent of whom are minorities. Thus, we are making progress, but we need to do even more.

Another clinical trial of great significance to type 2 diabetes is the Study of Health Outcomes of Weight Loss (SHOW), which we expect will begin shortly. This large, multicenter trial is designed to study if interventions to produce sustained weight loss in obese individuals with type 2 diabetes will improve health. The SHOW is expected to recruit approximately 6,000 patients over a three-year period with four additional years of treatment and follow-up. A goal of the trial is to have the overall ethnic and racial composition of the recruited patient populations reflect the prevalence rates for diabetes in the United States . We anticipate that SHOW will include participants from a range of Hispanic populations, including at least 360 Mexican Americans; however, the study population mix at any one center may vary from this overall distribution based on local demography. The NIDDK is sponsoring this trial along with the National Heart, Lung, and Blood Institute (NHLBI), the National Institute of Nursing Research (NINR), the Office of Research on Minority Health (ORMH), the Office of Research on Women's Health (ORWH), and the CDC.

The major goal of basic fundamental research is to create targets for therapeutic intervention. These basic discoveries provide the platform for drug testing by the biotechnology and pharmaceutical industry. An important research goal is to extend the therapeutic arsenal of safe and effective drugs to treat type 2 diabetes. In the United States, five classes of oral medications, each of which works through a different mechanism of action, are currently available to improve blood glucose control in patients with type 2 diabetes. These oral agents complement, in an important way, a variety of new insulin preparations that have been introduced for treatment, as well as multiple agents for the treatment of lipid and blood pressure disorders.

TYPE 2 DIABETES IN CHILDREN, ADOLESCENTS, AND YOUNG ADULTS

Type 2 diabetes has traditionally been considered a disease of adults because the age of onset is frequently after age 40 and it is often associated with obesity. Children with diabetes are usually presumed to have type 1 diabetes, an autoimmune disease. In recent years, however, an increasing number of children who appear with elevated blood glucose levels actually have type 2 diabetes. In some studies, the percentage of children with diabetes who have type 2 diabetes has risen from less than five percent prior to 1994, to 20 to 30 percent after 1994. Not surprisingly, one of the major risk factors for type 2 diabetes in children is obesity. The increase in reports of type 2 diabetes among children parallels a similar rise in the adult population, as obesity has become a major public health concern. In children, the alarming rise in the incidence of type 2 diabetes appears to be occurring largely in minority populations--Hispanic Americans, African Americans, and Native Americans.

The NIDDK recently convened a group of epidemiologists and pediatric endocrinologists to address this issue. Based on data presented at that meeting, we plan to solicit research on the pathophysiology, prevention and treatment of type 2 diabetes in children. The National Diabetes Education Program (NDEP) also plans to develop a campaign to alert pediatricians to this alarming trend.

MAJOR EPIDEMIOLOGICAL STUDIES OF DIABETES IN HISPANIC AMERICANS

A "Diabetes in America, 2nd Edition," is a compendium of data about the impact of diabetes, which has been compiled by the National Diabetes Data Group (NDDG) of the NIDDK. The NDDG was established in 1977 in response to recommendations of the U.S. National Commission on Diabetes. Its purposes are to define needs for information that can address the important scientific and public health issues in diabetes, facilitate research on the epidemiological and clinical aspects of diabetes, and develop reliable and accurate information on the scope and impact of diabetes in the U.S. population.

Through these efforts and other epidemiological research, a great deal has been learned about diabetes in parts of the Hispanic community, particularly in Mexican Americans. Most of this information has come from four studies: the San Antonio Heart Study (Texas), the San Luis Valley Diabetes Study (Colorado), the Starr County Study (Texas), and the Hispanic Health and Nutrition Examination Survey (HHANES). These studies have established that the prevalence of type 2 diabetes is two to three times higher in Mexican Americans than in non-Hispanic Caucasians. HHANES, conducted by the CDC's National Center for Health Statistics with support from NIDDK for the diabetes component of the study, is the only one of the four studies that included information on Cuban Americans in the Miami area and on Puerto Ricans in the New York City area.

OUTREACH AND EDUCATION PROGRAMS

The NIDDK initiated the National Diabetes Education Program (NDEP) in 1995, with the CDC, and with support from the NIH Office of Research on Minority Health (ORMH). A goal of this program is to improve the treatment and outcome for people with diabetes in order to reduce the illness and death associated with diabetes and its complications. Because survey research showed that the level of awareness of diabetes among the public was low, the program launched a media campaign aimed at people with diabetes in June 1998, with the theme, "Control Your Diabetes. For Life." The aim of this campaign was to disseminate the findings from our major clinical trial, which showed that close control of blood glucose levels can prevent or reduce the complications of diabetes. In national and local media outlets across the country, the message that diabetes is serious, common, costly, yet controllable, received excellent coverage.

Because of the extremely high incidence of diabetes in all minority groups, the NDEP quickly moved to target these audiences with culturally-sensitive public health messages tailored by minority organizations (National Council on Aging and the National Council of La Raza) who belonged to the NDEP Partnership. The Hispanic/Latino campaign recently won an Award of Excellence from the Health Improvement Institute and the 1998 Silver Mercury Award from the International Academy of Communications, Arts and Sciences/MerComm, Inc. Print and broadcast news stories reached audiences of 12.5 million Hispanics and Latinos in the United States and Puerto Rico by September 1998. A new wave of campaign media materials will include an English version, "Lightning and Thunder," for English-speaking Latinos. Complementing these education campaigns are the efforts of the National Diabetes Information Clearinghouse (NDIC), established to increase knowledge and understanding about diabetes among patients, health care professionals, and the public. To carry out this mission, the Clearinghouse works closely with the diabetes community to identify and respond to informational needs about diabetes and its management. Many fact sheets and pamphlets about diabetes are available in Spanish formats.

The NIDDK also funds research on the development of model education programs through its Diabetes Research and Training Centers (DRTCs), as well as through research grants. A major function of the DRTC program is to generate the most competent professional personnel, and to identify ways through which advances in the field of diabetes research can be translated as quickly as possible into improved care for the patient. Activities at a number of NIDDK-supported Diabetes Centers have a focus on minority populations, including Hispanics. The administrative guidelines for the Centers program state, "The NIDDK is concerned with the disproportionate prevalence of diabetes in minority groups and the increased susceptibility to the complications of diabetes in these groups. There is accordingly a requirement for DRTCs to develop programs and/or materials directed at minority populations." A DRTC that has had a major focus on diabetes in Hispanic populations is located at the University of Chicago. Four major projects, the MidWest Clinicians' Network Project, the "For Your Health" Program, the Chicago Hispanic Health Coalition Resource Guide, and the Neighborhood Clinic Diabetes Initiative Project, are supported by the Chicago DRTC and are relevant to diabetes in the Hispanic community. In addition to programs conducted through the DRTCs, the NIDDK also supports regular research grants studying culturally-sensitive lifestyle interventions. An example is at the University of Texas in Austin, where an NIDDK-funded investigator has designed an education and support program for Hispanic diabetics. The purpose of this project is to develop culturally-relevant, community-based interventions aimed at improving the health of diabetic Mexican Americans and their families. The intervention is provided in Spanish and is directed by Hispanic health care providers.