Tobacco, cannabis, alcohol, and polysubstance use disparities among sexual identity groups of US young adult women and men

Background: Sexual minority young adults (SMYAs) display higher rates of polysubstance use (i.e., current use of multiple substances) than their heterosexual peers, but limited research has explored differences by gender and specific sexual identity. Methods: Latent class analyses (LCAs) examined past-month use of combustible tobacco (i.e., cigarettes, cigars, hookah), e-cigarettes, cannabis, and alcohol among 2,343 YAs ( M age = 24.69, SD = 4.70; 57.4 % women, 42.6 % men; 18.0 % bisexual, 9.4 % gay or lesbian; 36.2% racial/ethnic minority) residing in 6 US metropolitan areas. Multinomial logistic regressions examined associations among sexual identity (bisexual, gay/lesbian, heterosexual) and polysubstance use classes among women (n = 1,345) and men (n = 998), separately. Results: LCA yielded a 5-class solution: primarily-alcohol use (29.5%), polysubstance use (i.e., use of all 4 substances, 24.3%), non-use (18.1%), cannabis and alcohol co-use (16.3%), and e-cigarette, cannabis, and alcohol co-use (11.8%). Bisexual and lesbian (vs. heterosexual) women displayed lower odds of primarily-alcohol use, whereas bisexual (vs. heterosexual) women displayed higher odds of polysubstance use, as well as e-cigarette, cannabis, and alcohol co-use. Bisexual (vs. heterosexual) men displayed lower odds of primarily-alcohol use, whereas gay (vs. heterosexual) men displayed lower odds of polysubstance use, as well as e-cigarette, cannabis, and alcohol co-use. Conclusions: Bisexual women were at greatest risk for polysubstance use of combustible tobacco, e-cigarettes, cannabis, and alcohol, whereas bisexual and gay men were at lower risk than heterosexual men for polysubstance use. Results underscore the need for tailored interventions and campaigns to consider patterns of co-occurring tobacco, cannabis, and alcohol use, particularly for bisexual women.