Sexual orientation and gender identity disparities in substance use disorders during young adulthood in a United States longitudinal cohort.

Background: This study examined associations of sexual orientation and gender identity with prevalence of substance use disorders (SUDs) and co-occurring multiple SUDs in the past 12-months during young adulthood in a United States longitudinal cohort.

Methods: Questionnaires self-administered in 2010 and 2015 assessed probable past 12-month nicotine dependence, alcohol abuse and dependence, and drug abuse and dependence among 12,428 participants of an ongoing cohort study when they were ages 20-35 years. Binary or multinomial logistic regressions using generalized estimating equations were used to estimate differences by sexual orientation and gender identity in the odds of SUDs and multiple SUDs, stratified by sex assigned at birth.