|  | |||||||||||
 |
| |||||||||||
|
Initiation of Marijuana Use: Trends, Patterns, and Implications | ||||||||||||
This chapter presents findings on (a) the demographic and prior substance use characteristics of recent marijuana initiates (i.e., 1998 and 1999 marijuana initiates), (b) the seasonality of incidence, and (c) potential predictors of marijuana initiation. These data provide descriptive information about young people who have recently initiated use of marijuana. This information can suggest potential approaches to prevention efforts and may also indicate issues that deserve further research to more fully understand the underlying factors involved in marijuana initiation.
Little prior research has been conducted on the characteristics and predictors of marijuana initiation. Most research on correlates has focused on use, not initiation. Factors associated with marijuana initiation include individuals' personality characteristics, adverse family factors, lower level of parental attachment, low parental monitoring, parental substance use, and peers' influences (Bailey & Hubbard, 1990; Brook et al., 1998a; Chilcoat & Anthony, 1996; Kandel, Griesler, Davies, & Schaffsan, 2001; Van Etten & Anthony, 1999).
Rates of first marijuana use also are influenced by demographic characteristics and by prior use of licit substances. Male youths tended to initiate marijuana use earlier than female youths (Kandel & Logan, 1984; Warren et al., 1997). However, younger cohorts of females appeared to initiate marijuana at earlier ages than older cohorts (Warren et al., 1997). Onset of marijuana use was also strongly correlated with age. The rate of marijuana initiation remained relatively flat up to about 13 years of age and increased over the succeeding 5 years (Kosterman et al., 2000). First use of marijuana rarely occurred after age 21, with the period of highest risk peaking at around age 17 and declining sharply thereafter (Kandel & Logan, 1984; Kandel & Yamaguchi, 1985).
In addition, the use of licit substances, such as cigarettes and alcohol, has been suggested to play a role in marijuana initiation. Studies have found that alcohol and/or tobacco tended to precede the use of marijuana, which in turn was followed by the use of other illicit or hard drugs (Duncan, Duncan, & Hops, 1998; Ellickson et al., 1992; Fleming, Leventhal, Glynn, & Ershler, 1989; Kandel et al., 1992; Kandel & Yamaguchi, 1985; Yamaguchi & Kandel, 1984). Both current and prior use of marijuana was found to influence the initiation of other illicit drugs among men and women (Kandel & Yamaguchi, 1985).
Research on the developmental sequence of substance use has suggested that gateway drug use may not be generalized to all substance users. An increasing number of studies havereported racial/ethnic differences in rates of substance initiation, including marijuana. These observed differences have been suggested to be associated with different family and/or cultural factors (Catalano et al., 1992) or with differential availability of substances and parental attitudes toward substance use (Gillmore et al., 1990). Neumark-Sztainer et al. (1996) found that African-American students had a relatively lower prevalence of tobacco use, but a higher prevalence of marijuana use, than students of other racial/ethnic groups. Gillmore et al. (1990) reported that initiation rates of gateway drugs differed by race/ethnicity and gender. They found that, among 5th graders, white students reported higher rates of initiation of alcohol and tobacco than black or Asian students. White and Asian-American females were less likely than their male counterparts to have engaged in substance use; however, black females were more likely than black males to have used tobacco, alcohol, and marijuana (Gillmore et al., 1990). Recent NHSDA analyses of youth respondents have identified some significant racial/ethnic differences in factors that might be associated with substance use (e.g., access to illicit drugs, parental supervision, and religious beliefs) (Lane et al., 2001).
Similarly, descriptive 1999 NHSDA estimates of persons aged 20 to 25 have suggested that neither cigarettes nor alcohol appeared to be a compelling trigger for subsequent marijuana use because there was no fixed pattern of progression from cigarettes or alcohol to marijuana at the national level (Wright & Davis, 2001). In fact, a large proportion of persons aged 20 to 25 reported never using marijuana, and only one third reported either starting with cigarettes and going on to marijuana or starting with alcohol then going on to marijuana. Depending on prior use of a specific substance, the lag between first use of alcohol and first use of marijuana, or between first use of cigarettes and first use of marijuana, also varied widely (Wright & Davis, 2001).
Prior to this report, there were no data on the seasonality of marijuana initiation. Few available data suggest a potential seasonality in marijuana use. The analysis of data from reports of arrests found a seasonal fluctuation, with the highest marijuana arrest rates during the summer months (peaking in June or July) and the lowest arrest rates in the winter months (Zingraff & Belyea, 1983). Kovalenko et al. (2000) conducted a cross-sectional study to determine when the symptoms of marijuana use and other psychiatric disorders were highest over a 12-month period. They found significant seasonal variations in symptom counts of marijuana use. Symptom counts of marijuana use reached their nadir in February and March and their zenith in August and September.
The characteristics of 1998 and 1999 marijuana initiates were examined using data from the 1999 and 2000 surveys. Estimated proportions of recent new marijuana users by gender and race/ethnicity are summarized in Table 5.1. In 1998 and 1999, there were 2.3 million male initiates and 2.2 million female initiates. For both genders, approximately 70 percent of these recent new marijuana users were white, 3 percent were Asian or Pacific Islander or Native Hawaiian, and 1 percent each were American Indian/Alaska Native or persons reporting more than one race. Of all new male users, 11.7 percent were black, while 14.2 percent of all new female users were black. In comparison, 14.1 percent of all new male users were Hispanic and 10.8 percent of all new female users were Hispanic.
Overall, only 1.5 percent of all recent new users initiated marijuana use before age 12 and 5.5 percent initiated at age 26 or older (Table 5.1). An increased proportion of recent initiates was noted between the ages of 13 and 18, ranging from 9 to 15 percent for each age, then it declined sharply thereafter with increasing age (Figure 5.1). Specifically, 4.4 percent of new users had started to use marijuana at age 12. The proportion of first-time users jumped to 9.3 percent at age 13 and peaked at age 15 (15.1 percent). It was 14.2 percent at age 16, decreasing to 11.3 percent at age 17, 9.0 percent at age 18, and 5.0 percent at age 19. A similar age of initiation pattern was observed for both genders. For males, the highest proportion of all recent initiates was at ages 15 and 16 (both at 14.8 percent); for females, it was at age 15 (15.4 percent). A slightly higher proportion of male than female initiates started to use marijuana before age 12 (2.0 vs. 0.9 percent).
Data on the prior use of alcohol and/or cigarettes in relation to gender and age of first marijuana use among recent marijuana initiates are displayed in Table 5.2. Approximately 60 percent of recent initiates reported prior use of both alcohol and cigarettes. About 9 percent had never used alcohol or cigarettes in their lifetime, and the remaining recent initiates had used either alcohol only (16.6 percent) or cigarettes only (14.8 percent) in their lifetime (Figure 5.2). For both genders, early-onset marijuana users (before age 15) reported a higher proportion of prior use of cigarettes only than those starting their use at age 15 or older. By comparison, adult-onset marijuana users reported a higher proportion of prior use of alcohol only than those starting their use at a younger age. Early-onset marijuana users were also much more likely than other initiates to have begun using marijuana prior to any use of cigarettes or alcohol.
Figure 5.1 Recent Marijuana Initiates, by Age at First Use
Note:
Recent initiates are persons who used marijuana for the first time in 1998 or
1999.
Source: SAMHSA, Office
of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.
Figure 5.2 Prior Alcohol and Cigarette Use among Recent Marijuana Initiates, by Gender
Note:
Recent initiates are persons who used marijuana for the first time in 1998 or
1999.
Source: SAMHSA, Office
of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.
The distribution of month of first marijuana use is presented by gender and age of first marijuana use (Table 5.3). Overall and for males, the highest peak of recent marijuana initiation was noted in June and July (Figure 5.3). Approximately 21 percent of all recent initiates or 22 percent of male initiates reported initiating their marijuana use in these 2 months. For females, the month with the highest proportion of recent initiates was in January (10.0 percent) and July (10.3 percent), while there was a much lower proportion of initiates in February (5.8 percent).
Figure 5.3 shows the overall and gender-specific average number of new marijuana users per day for each month. On average, there were 3,197 male initiates and 2,989 female initiates per day. Among males, this number of daily initiates increased to approximately 4,300 in June and July. Among females, the estimated initiates per day rose to 3,625 in July and 3,519 in January. Of all recent initiates who started using marijuana before age 18, June (11.6 percent) and July (12.0 percent) also had the most new users, while adult-onset marijuana users tended to have initiated use in January (10.9 percent), December (9.2 percent), or July (9.1 percent).
Figure 5.3 Estimated Average Number of Marijuana Initiates Per Day for Each Month: Overall and by Gender
Note:
Estimates are based on respondents who gave a substantive response to the month
of first use question; hence, only those respondents who did not require their
month of first use to be imputed are included. Initiates are defined as those
respondents whose difference between their current age and age of first using
marijuana is less than 2 years. The average number of initiates per day was calculated
by applying the percentage distribution (Table 5.3) to the estimated number of
initiates in 1998 and 1999 (Table 3.1) and adjusting for the number of days in
each month.
Source: SAMHSA,
Office of Applied Studies, National Household Survey on Drug Abuse, 1999 and 2000.
Data on potential predictors of marijuana initiation provide important information for prevention and treatment interventions. This section reports the findings about suspected predictors of recent marijuana initiation (defined as first use in 1998 for the 1999 NHSDA and first use in 1999 for the 2000 NHSDA). Logistic regression procedures were used to determine the relationship between prior use of alcohol and/or cigarettes and marijuana initiation among persons aged 12 to 25 years (age on January 1st). The analysis sample included persons in the 1999 NHSDA who had never used marijuana as of January 1, 1998, and persons in the 2000 NHSDA who had never used marijuana as of January 1, 1999. Of this sample, 5.6 percent (weighted estimate) initiated marijuana use within 1 year (i.e., by December 31th, 1998, in the 1999 sample and by December 31th, 1999, in the 2000 sample).
Prior cigarette use, alcohol use, and daily cigarette use were examined as predictors of marijuana initiation during a 1-year period. Using data about the date of first use, three categories of onset variables for use of alcohol and cigarettes were defined: (1) initial use at age 13 or younger, (2) initial use at age 14 or older, and (3) no use. The following characteristics were also included in the logistic regression models: age, gender, race/ethnicity, geographic region, and population density. In the model for youths aged 12 to 14, two categories of prior use of alcohol and/or cigarettes were defined (i.e., ever used vs. never used). In these logistic regression analyses, age was defined as "age as of January 1, 1998" in the 1999 NHSDA and "age as of January 1, 1999" in the 2000 NHSDA. Five separate logistic regression models were reported for five age groups: 12 to 25 years, 12 to 14 years, 15 to 17 years, 18 to 20 years, and 21 to 25 years (Tables 5.4 to 5.8). Schooling status, employment, and marital status were also examined in the two models for adults aged 18 to 20 and 21 to 25.
Adjusted odds ratios (ORs) of recent marijuana initiation and corresponding 95 percent confidence intervals (CIs) from a multiple logistic regression analysis of persons aged 12 to 25 are summarized in Table 5.4. The model included age, gender, race/ethnicity, region of residence, population density, and prior use of alcohol or cigarettes (i.e., any cigarette smoking, daily cigarette smoking, any alcohol use).
Antecedent use of alcohol or cigarettes and all demographics examined in the model were found to be associated with recent marijuana initiation. Consistent with the literature and the descriptive analyses, the odds of becoming a new marijuana user were relatively low among persons aged 21 to 25 compared with those under age 21. Relative to adults aged 21 to 25, youths aged 17 or younger had particularly increased odds of initiating use (OR = 9.6 for youths aged 12 to 15; OR = 8.4 for youths aged 15 to 17). In this model, males were only slightly more likely than females to initiate marijuana use (OR = 1.1). Whites, Hispanics, and Asians or Pacific Islanders or Native Hawaiians, relative to blacks, had decreased odds of starting to use marijuana, while American Indians or Alaska Natives were more likely than blacks to do so (OR = 2.0). There was no significant difference in the odds of marijuana initiation between blacks and persons reporting more than one race. Persons living in the West were significantly more likely than those in other U.S. regions to become initiates. Increased rates of new use also were more likely among persons living in either large or small metropolitan areas than those in nonmetropolitan areas.
In addition, prior use of alcohol or cigarettes was highly associated with becoming a new marijuana user. Regardless of onset age, cigarette smokers were an estimated 6 times more likely than nonsmokers to initiate marijuana use. Alcohol users were an estimated 7 to 9 times more likely than nonusers to start using marijuana. Daily cigarette smoking was associated with a twofold increase in risk for marijuana initiation.
Among youths aged 12 to 14 (Table 5.5), the odds of becoming a new marijuana user increased with increasing age. Males were an estimated 1.5 times more likely than females to start using marijuana. Black youths had greater odds of initiation than white youths, but there were no significant differences between blacks and other racial/ethnic groups. The West relative to the Northeast and South regions and small metropolitan areas relative to nonmetropolitan areas had increased rates of marijuana initiation. Antecedent use of cigarettes and alcohol was highly associated with the risk of onset of marijuana use (OR = 12.0 for any cigarette use, OR = 4.0 for daily cigarette use, and OR = 5.6 for any alcohol use).
Age, as a continuous variable, was associated with decreased risk of marijuana initiation in the adjusted logistic regression model of youths aged 15 to 17 (Table 5.6). Gender was not related to marijuana initiation. American Indian or Alaska Native youths had the highest odds of becoming new marijuana users, and blacks had higher odds than whites and Asians, Pacific Islanders, or Native Hawaiians. Youths living in the West or metropolitan areas also had increased odds of becoming new marijuana users. Consistent with the model for youths aged 12 to 14, prior use of alcohol or cigarettes signaled elevated odds of marijuana initiation. Regardless of the age group of onset, the adjusted ORs of marijuana initiation were around 6.0 for any alcohol or cigarette use and 2.0 to 3.0 for daily cigarette use.
Among young adults aged 18 to 20 (Table 5.7), increased age was associated with decreased risk of marijuana initiation. In this adult age group, education, employment, and marital status were also included in the logistic regression model. Gender, education, employment, and region of residence were not found to be associated with marijuana initiation. Blacks, relative to Hispanics, had increased odds of initiation. Being married was associated with decreased odds of initiation compared with being never married. Young adults living in large metropolitan areas were more likely than those in nonmetropolitan areas to initiate marijuana use. Antecedent use of alcohol or cigarettes increased the risk of recent marijuana initiation (OR ~ 4.0 for any cigarette use, OR ~ 8.0 for any alcohol use). Onset of daily cigarette smoking at age 14 or older predicted an onset of marijuana use (OR = 1.9), while onset before age 14 was not found to be significant.
Consistent with previous analyses, the risk of marijuana initiation among adults aged 21 to 25 decreased with older age (Table 5.8). In this age group, gender, employment, region of residence, and population density were not found to be associated with marijuana initiation. Blacks, relative to whites, Hispanics, or Asians/Pacific Islanders/Native Hawaiians, had increased odds of initiation. Young adults aged 21 to 25 who attended college had greater odds of becoming new marijuana users than high school graduates. Married persons had decreased odds of initiation compared with those who had never been married. Prior use of alcohol or any cigarette and daily cigarette smoking at age 14 or older predicted increased odds of initiation, but daily cigarette smoking before age 14 predicted decreased odds of initiation.
Table 5.1 Characteristics of Recent Marijuana Initiates | ||||||||
Characteristics | Total | Male | Female | |||||
Number of Initiates (1,000s) | % | Number of Initiates (1,000s) | % | Number of Initiates (1,000s) | % | |||
Total | 4,515 | 100.0 | 2,302 | 100.0 | 2,214 | 100.0 | ||
Race/Ethnicity | ||||||||
White | 3,138 | 69.5 | 1,587 | 68.9 | 1,551 | 70.1 | ||
Black | 584 | 12.9 | 269 | 11.7 | 315 | 14.2 | ||
Hispanic | 565 | 12.5 | 326 | 14.1 | 240 | 10.8 | ||
Asian/Pacific Islander/
| 120 | 2.7 | 61 | 2.6 | 59 | 2.7 | ||
American Indian or
| 49 | 1.1 | 25 | 1.1 | 24 | 1.1 | ||
More than one race | 60 | 1.3 | 35 | 1.5 | 25 | 1.1 | ||
Age at First Marijuana Use | ||||||||
< 12 | 66 | 1.5 | 45 | 2.0 | 20 | 0.9 | ||
12 | 200 | 4.4 | 104 | 4.5 | 97 | 4.4 | ||
13 | 422 | 9.3 | 240 | 10.4 | 182 | 8.2 | ||
14 | 572 | 12.7 | 282 | 12.2 | 290 | 13.1 | ||
15 | 681 | 15.1 | 340 | 14.8 | 341 | 15.4 | ||
16 | 642 | 14.2 | 341 | 14.8 | 301 | 13.6 | ||
17 | 509 | 11.3 | 285 | 12.4 | 224 | 10.1 | ||
18 | 404 | 9.0 | 206 | 8.9 | 198 | 9.0 | ||
19 | 225 | 5.0 | 102 | 4.4 | 124 | 5.6 | ||
20 | 181 | 4.0 | 79 | 3.4 | 102 | 4.6 | ||
21 | 121 | 2.7 | 53 | 2.3 | 68 | 3.1 | ||
22 | 83 | 1.8 | 35 | 1.5 | 49 | 2.2 | ||
23 | 61 | 1.3 | 28 | 1.2 | 32 | 1.5 | ||
24 | 53 | 1.2 | 26 | 1.1 | 26 | 1.2 | ||
25 | 46 | 1.0 | 26 | 1.1 | 20 | 0.9 | ||
26 or older | 249 | 5.5 | 110 | 1.8 | 139 | 6.3 | ||
Note:
Recent initiates are persons who used marijuana for the first time in 1998 based
on both 1999 and 2000 NHSDA data or for the first time in 1999 based on 2000 NHSDA
data only. | ||||||||
Table 5.2 Prior Alcohol and Cigarette Use among Recent Marijuana Initiates | ||||||||
Gender
and Age of | Alcohol and Cigarette Use at Time of Marijuana Initiation | |||||||
Never Used Alcohol | Used Cigarettes, | Used
Alcohol, But | Used Both Alcohol | |||||
% of Marijuana | % of Marijuana | % of Marijuana | % of Marijuana | |||||
Total | ||||||||
Total | 9.1 | 14.8 | 16.6 | 59.5 | ||||
< 15 | 16.5 | 24.2 | 13.1 | 46.2 | ||||
15-17 | 9.0 | 16.4 | 15.3 | 59.3 | ||||
18-20 | 4.3 | 6.8 | 21.2 | 67.8 | ||||
21 or older | 0.5 | 1.3 | 21.6 | 76.7 | ||||
Male | ||||||||
Total | 9.7 | 16.5 | 16.0 | 57.8 | ||||
< 15 | 16.8 | 26.1 | 13.7 | 43.4 | ||||
15-17 | 9.9 | 18.1 | 14.9 | 57.1 | ||||
18-20 | 3.3 | 7.0 | 19.9 | 69.8 | ||||
21 or older | 0.7 | 0.9 | 20.3 | 78.1 | ||||
Female | ||||||||
Total | 8.5 | 13.1 | 17.1 | 61.3 | ||||
< 15 | 16.1 | 22.1 | 12.4 | 49.4 | ||||
15-17 | 8.0 | 14.6 | 15.7 | 61.6 | ||||
18-20 | 5.3 | 6.5 | 22.3 | 65.9 | ||||
21 or older | 0.3 | 1.7 | 22.6 | 75.5 | ||||
Note: Recent
initiates are persons who used marijuana for the first time in 1998 based on either
1999 or 2000 NHSDA data or for the first time in 1999 based on 2000 NHSDA data
only. | ||||||||
Table 5.3 Distribution of Month of First Marijuana Use among Persons Aged 12 or Older | |||||
Month | % of Initiates | ||||
Total | Male | Female | Initiating Marijuana Before Age 18 | Initiating Marijuana >18 | |
Total | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
January | 9.2 | 8.2 | 10.0 | 7.8 | 10.9 |
February | 7.0 | 8.3 | 5.8 | 6.9 | 7.1 |
March | 7.6 | 7.7 | 7.5 | 6.7 | 8.8 |
April | 7.5 | 6.9 | 8.0 | 7.5 | 7.5 |
May | 7.7 | 7.7 | 7.7 | 7.5 | 7.9 |
June | 10.0 | 11.1 | 9.0 | 11.6 | 8.0 |
July | 10.8 | 11.3 | 10.3 | 12.0 | 9.1 |
August | 8.1 | 7.5 | 8.8 | 8.1 | 8.2 |
September | 8.0 | 8.1 | 7.8 | 8.9 | 6.8 |
October | 8.9 | 8.5 | 9.4 | 9.8 | 7.9 |
November | 7.8 | 7.2 | 8.4 | 7.2 | 8.6 |
December | 7.4 | 7.5 | 7.3 | 6.0 | 9.2 |
Note:
Estimates are based on respondents who gave a substantive response to the month
of first use question; hence, only those respondents who did not require their
month of first use to be imputed are included. Initiates are defined as those
respondents whose difference between their current age and age of first using
marijuana is less than 2 years. | |||||
Table 5.4 Adjusted Odds Ratios of Marijuana Initiation Within 1 Year among Persons Aged 12 to 25 | ||||
Model Covariates | Adjusted Odds Ratio | 95% | ||
Age on January 11 | ||||
Under 15 | 9.58 | (7.76 | - | 11.82) |
15-17 | 8.40 | (6.87 | - | 10.26) |
18-20 | 3.29 | (2.63 | - | 4.13) |
21 or older | 1.00 | (1.00 | - | 1.00) |
Gender | ||||
Male | 1.12 | (1.03 | - | 1.22) |
Female | 1.00 | (1.00 | - | 1.00) |
Race/Ethnicity | ||||
White | 0.65 | (0.56 | - | 0.76) |
Black | 1.00 | (1.00 | - | 1.00) |
Hispanic | 0.62 | (0.51 | - | 0.75) |
Asian/Pacific Islander/Native Hawaiian | 0.56 | (0.40 | - | 0.80) |
American Indian or Alaska Native | 2.03 | (1.25 | - | 3.29) |
More than one race | 0.85 | (0.55 | - | 1.32) |
Region | ||||
Northeast | 0.84 | (0.72 | - | 0.98) |
Midwest | 0.80 | (0.69 | - | 0.92) |
South | 0.74 | (0.64 | - | 0.85) |
West | 1.00 | (1.00 | - | 1.00) |
Population Density | ||||
Large metro | 1.30 | (1.15 | - | 1.47) |
Small metro | 1.29 | (1.15 | - | 1.46) |
Nonmetro | 1.00 | (1.00 | - | 1.00) |
Cigarette Use | ||||
Initiation at age 13 or younger | 5.58 | (4.81 | - | 6.48) |
Initiation at age 14 or older | 5.68 | (4.90 | - | 6.60) |
Never used | 1.00 | (1.00 | - | 1.00) |
Daily Cigarette Use | ||||
Initiation at age 13 or younger | 2.05 | (1.71 | - | 2.46) |
Initiation at age 14 or older | 1.96 | (1.75 | - | 2.20) |
Never used | 1.00 | (1.00 | - | 1.00) |
Alcohol Use | ||||
Initiation at age 13 or younger | 7.26 | (6.08 | - | 8.67) |
Initiation at age 14 or older | 9.00 | (7.51 | - | 10.78) |
Never used | 1.00 | (1.00 | - | 1.00) |
Note:
Recent initiation is defined as starting in the calendar year 1998 based on 1999
data or starting in the calendar year 1999 based on 2000 data. | ||||
Table 5.5 Adjusted Odds Ratios of Marijuana Initiation Within 1 Year among Persons Aged 12 to 14 | ||||
Model Covariates | Adjusted Odds Ratio | 95% | ||
Age on January 11 | 1.30 | (1.14 | - | 1.48) |
Gender | ||||
Male | 1.47 | (1.20 | - | 1.79) |
Female | 1.00 | (1.00 | - | 1.00) |
Race/Ethnicity | ||||
White | 0.56 | (0.41 | - | 0.78) |
Black | 1.00 | (1.00 | - | 1.00) |
Hispanic | 1.08 | (0.71 | - | 1.64) |
Asian/Pacific Islander/Native Hawaiian | 0.67 | (0.24 | - | 1.86) |
American Indian or Alaska Native | 3.08 | (0.98 | - | 9.71) |
More than one race | 0.55 | (0.26 | - | 1.17) |
Region | ||||
Northeast | 0.68 | (0.48 | - | 0.96) |
Midwest | 0.76 | (0.56 | - | 1.02) |
South | 0.63 | (0.47 | - | 0.86) |
West | 1.00 | (1.00 | - | 1.00) |
Population Density | ||||
Large metro | 1.12 | (0.86 | - | 1.47) |
Small metro | 1.61 | (1.25 | - | 2.08) |
Nonmetro | 1.00 | (1.00 | - | 1.00) |
Cigarette Use | ||||
Ever used | 12.00 | (8.50 | - | 16.94) |
Never used | 1.00 | (1.00 | - | 1.00) |
Daily Cigarette Use | ||||
Ever used | 3.95 | (2.91 | - | 5.36) |
Never used | 1.00 | (1.00 | - | 1.00) |
Alcohol Use | ||||
Ever used | 5.55 | (4.02 | - | 7.67) |
Never used | 1.00 | (1.00 | - | 1.00) |
Note:
Recent initiation is defined as starting in the calendar year 1998 based on 1999
data or starting in the calendar year 1999 based on 2000 data. | ||||
Table 5.6 Adjusted Odds Ratios of Marijuana Initiation Within 1 Year among Persons Aged 15 to 17 | ||||
Model Covariates | Adjusted Odds Ratio | 95% | ||
Age on January 11 | 0.90 | (0.84 | - | 0.97) |
Gender | ||||
Male | 1.08 | (0.95 | - | 1.23) |
Female | 1.00 | (1.00 | - | 1.00) |
Race/Ethnicity | ||||
White | 0.63 | (0.51 | - | 0.79) |
Black | 1.00 | (1.00 | - | 1.00) |
Hispanic | 0.79 | (0.60 | - | 1.04) |
Asian/Pacific Islander/Native Hawaiian | 0.45 | (0.27 | - | 0.75) |
American Indian or Alaska Native | 2.62 | (1.13 | - | 6.10) |
More than one race | 1.06 | (0.55 | - | 2.02) |
Region | ||||
Northeast | 0.85 | (0.70 | - | 1.04) |
Midwest | 0.74 | (0.61 | - | 0.91) |
South | 0.70 | (0.58 | - | 0.84) |
West | 1.00 | (1.00 | - | 1.00) |
Population Density | ||||
Large metro | 1.35 | (1.14 | - | 1.59) |
Small metro | 1.29 | (1.10 | - | 1.51) |
Nonmetro | 1.00 | (1.00 | - | 1.00) |
Cigarette Use | ||||
Initiation at age 13 or younger | 6.09 | (4.99 | - | 7.42) |
Initiation at age 14 or older | 6.14 | (5.07 | - | 7.44) |
Never used | 1.00 | (1.00 | - | 1.00) |
Daily Cigarette Use | ||||
Initiation at age 13 or younger | 2.16 | (1.66 | - | 2.81) |
Initiation at age 14 or older | 3.15 | (2.68 | - | 3.70) |
Never used | 1.00 | (1.00 | - | 1.00) |
Alcohol Use | ||||
Initiation at age 13 or younger | 6.18 | (4.91 | - | 7.77) |
Initiation at age 14 or older | 6.47 | (5.21 | - | 8.03) |
Never used | 1.00 | (1.00 | - | 1.00) |
Note:
Recent initiation is defined as starting in the calendar year 1998 based on 1999
data or starting in the calendar year 1999 based on 2000 data. | ||||
Table 5.7 Adjusted Odds Ratios of Marijuana Initiation Within 1 Year among Persons Aged 18 to 20 | ||||
Model Covariates | Adjusted Odds Ratio | 95% Confidence Interval | ||
Age on January 11 | 0.73 | (0.66 | - | 0.82) |
Gender | ||||
Male | 1.19 | (0.99 | - | 1.44) |
Female | 1.00 | (1.00 | - | 1.00) |
Race/Ethnicity | ||||
White | 0.79 | (0.55 | - | 1.12) |
Black | 1.00 | (1.00 | - | 1.00) |
Hispanic | 0.49 | (0.31 | - | 0.77) |
Asian/Pacific Islander/Native Hawaiian | 0.56 | (0.29 | - | 1.07) |
American Indian or Alaska Native | 1.29 | (0.46 | - | 3.62) |
More than one race | 0.50 | (0.21 | - | 1.18) |
Education | ||||
High school dropout | 0.89 | (0.62 | - | 1.28) |
High school student | 0.86 | (0.67 | - | 1.12) |
High school graduate | 0.85 | (0.68 | - | 1.06) |
At least some college | 1.00 | (1.00 | - | 1.00) |
Employment Status | ||||
Not employed | 0.96 | (0.78 | - | 1.19) |
Employed | 1.00 | (1.00 | - | 1.00) |
Marital Status | ||||
Never married | 2.76 | (1.48 | - | 5.15) |
Married or previously married | 1.00 | (1.00 | - | 1.00) |
Region | ||||
Northeast | 0.81 | (0.58 | - | 1.14) |
Midwest | 0.87 | (0.64 | - | 1.19) |
South | 0.85 | (0.61 | - | 1.18) |
West | 1.00 | (1.00 | - | 1.00) |
Population Density | ||||
Large metro | 1.37 | (1.07 | - | 1.76) |
Small metro | 1.22 | (0.98 | - | 1.52) |
Nonmetro | 1.00 | (1.00 | - | 1.00) |
Cigarette Use | ||||
Initiation at age 13 or younger | 3.19 | (2.26 | - | 4.49) |
Initiation at age 14 or older | 3.95 | (3.04 | - | 5.15) |
Never used | 1.00 | (1.00 | - | 1.00) |
Daily Cigarette Use | ||||
Initiation at age 13 or younger | 1.32 | (0.70 | - | 2.48) |
Initiation at age 14 or older | 1.86 | (1.51 | - | 2.30) |
Never used | 1.00 | (1.00 | - | 1.00) |
Alcohol Use | ||||
Initiation at age 13 or younger | 7.41 | (4.08 | - | 13.44) |
Initiation at age 14 or older | 8.01 | (4.67 | - | 13.74) |
Never used | 1.00 | (1.00 | - | 1.00) |
Note:
Recent initiation is defined as starting in the calendar year 1998 based on 1999
data or starting in the calendar year 1999 based on 2000 data. | ||||
Table 5.8 Adjusted Odds Ratios of Marijuana Initiation Within 1 Year among Persons Aged 21 to 25 | ||||
Model Covariates | Adjusted Odds Ratio | 95% Confidence Interval | ||
Age on January 11 | 0.70 | (0.63 | - | 0.78) |
Gender | ||||
Male | 0.92 | (0.70 | - | 1.21) |
Female | 1.00 | (1.00 | - | 1.00) |
Race/Ethnicity | ||||
White | 0.52 | (0.36 | - | 0.75) |
Black | 1.00 | (1.00 | - | 1.00) |
Hispanic | 0.31 | (0.17 | - | 0.57) |
Asian/Pacific Islander/Native Hawaiian | 0.43 | (0.20 | - | 0.94) |
American Indian or Alaska Native | 0.85 | (0.19 | - | 3.91) |
More than one race | 1.79 | (0.57 | - | 5.64) |
Education | ||||
Not completed high school2 | 0.58 | (0.33 | - | 1.01) |
High school graduate | 0.43 | (0.30 | - | 0.60) |
At least some college | 1.00 | (1.00 | - | 1.00) |
Employment Status | ||||
Not employed | 1.08 | (0.76 | - | 1.53) |
Employed | 1.00 | (1.00 | - | 1.00) |
Marital Status | ||||
Never married | 2.13 | (1.41 | - | 3.23) |
Married or previously married | 1.00 | (1.00 | - | 1.00) |
Region | ||||
Northeast | 0.85 | (0.55 | - | 1.33) |
Midwest | 0.66 | (0.43 | - | 1.01) |
South | 0.76 | (0.50 | - | 1.15) |
West | 1.00 | (1.00 | - | 1.00) |
Population Density | ||||
Large metro | 1.08 | (0.77 | - | 1.51) |
Small metro | 1.02 | (0.73 | - | 1.42) |
Nonmetro | 1.00 | (1.00 | - | 1.00) |
Cigarette Use | ||||
Initiation at age 13 or younger | 2.85 | (1.69 | - | 4.81) |
Initiation at age 14 or older | 2.99 | (2.06 | - | 4.33) |
Never used | 1.00 | (1.00 | - | 1.00) |
Daily Cigarette Use | ||||
Initiation at age 13 or younger | 0.17 | (0.03 | - | 0.88) |
Initiation at age 14 or older | 1.50 | (1.10 | - | 2.03) |
Never used | 1.00 | (1.00 | - | 1.00) |
Alcohol Use | ||||
Initiation at age 13 or younger | 20.82 | (4.10 | - | 105.78) |
Initiation at age 14 or older | 29.27 | (6.46 | - | 132.71) |
Never used | 1.00 | (1.00 | - | 1.00) |
Note:
Recent initiation is defined as starting in the calendar year 1998 based on 1999
data or starting in the calendar year 1999 based on 2000 data. | ||||
This page was last updated on June 16, 2008. |
* Adobe™ PDF and MS Office™ formatted files require software viewer programs to properly read them.
Click here to download these FREE programs now
| Highlights | Topics | Data | Drugs | Pubs | Short Reports | Treatment | Help | OAS |
