Gender Differences in Substance Use Trajectories Among American Indian and White High School Students

Introduction: Previous research has evaluated trajectories of alcohol, tobacco and marijuana use among adolescents; however, there are few studies that analyze gender differences in trajectories and even fewer that include American Indian youth. American Indians are at higher risk for health disparities related to substance use. This research examines gender difference in the trajectories of alcohol, tobacco and marijuana use among American Indian and White adolescents.

Methods: Gender differences in longitudinal trajectories of alcohol, tobacco, and marijuana use will be evaluated among 684 adolescents (50% female) across 5 assessments over 9^th (3 waves) and 10^th grades (2 waves). Youth were drawn from 6 rural towns within the jurisdictional service boundaries of the Cherokee Nation. At wave 1, 54% of youth were White, 20% were both White and American Indian, and 26% were American Indian only.  Thirty-six percent of guardians attained a high school diploma or less and 51% of youth received free or reduced price lunch.  

Participants completed self-reported surveys on days of alcohol use, binge drinking, cigarette use, chewing tobacco use, and times used marijuana in the past month. Given low rates of monthly substance use, these variables were dichotomized into “used” vs. “did not use” with the exception of alcohol which was recoded “none”, “1 or 2 days”, “3 – 30 days”.

Growth mixture modeling was employed to determine the number and shape of trajectories for each substance accounting for outcome distributions. Missing data was imputed using full information maximum likelihood. Once patterns of individual substance use was determined, dual trajectories were evaluated to determine the extent to which individuals engage in multiple substance use. Gender differences in patterns of substance use was evaluated.

Results: Preliminary analyses of mean differences in substance use by gender support the plausibility of gender-specific patterns of tobacco, alcohol, and marijuana use. Females reported slightly higher or comparable levels of cigarette use, alcohol use, and binge drinking compared to males. Males reported higher chewing tobacco use and slightly higher or comparable levels of marijuana use compared to females.

Conclusion: Moving beyond mean differences and identifying gender differences in developmental patterns of substance use at this sensitive stage of development will inform gender-sensitive prevention programs targeting specific substance use. These results will be particularly informative given the lack of evidence regarding trajectories of substance initiation within largely American Indian populations.