PROJECT SUMMARY/ABSTRACT Young adulthood (YA) is a critical period for engaging in risk behaviors, including tobacco use, and establishing lifestyles with long-term health implications. The landscape of tobacco use in the US has changed in recent decades, with decreases in cigarette use coupled with increases in the use of alternative tobacco products (ATPs; electronic cigarettes, cigars, smokeless tobacco, hookah). These complexities are further compounded by an evolving tobacco policy context and increases in polytobacco use. The use of these products disproportionately impacts vulnerable subgroups, including sexual minority YAs. Identifying mechanisms accounting for sexual orientation disparities in traditional and ATP use is critical for informing interventions to reduce use and disparities. However, there is a substantial gap regarding the mechanisms that explain these disparities. Important predictors of YA tobacco use are parenting behaviors and mental health problems, which may have particularly strong influences for sexual minority YAs, given the multitude of community and social impacts on tobacco use during this time. This F32 application aims to catalyze Dr. Romm’s achievement of her career goal – to establish an independent research program devoted to elucidating multilevel determinants of health-risk behaviors among vulnerable adolescent and YA populations and inform interventions to prevent and reduce such behaviors. This proposal capitalizes on Dr. Romm’s existing skills and experience, and provides 1) training in advanced multilevel behavioral theories, health disparities, and intervention research; 2) mentored support for her professional development; and 3) resources for mentored and independent research to advance novel research at the intersection of: a) a particularly vulnerable population – sexual minority YAs; b) multilevel mechanisms that explain sexual orientation disparities in YA tobacco use; and c) use of both traditional and ATPs, highly relevant within today’s evolving tobacco context. More specifically, the training will directly enhance the skills and expertise Dr. Romm requires to execute the 3 research aims, to: 1) examine sexual orientation (distinguishing heterosexual, bisexual, and gay/lesbian) in relation to changes in use of traditional and ATPs among YA men and women; 2) document differential associations between parenting behaviors and tobacco use among male and female sexual minority versus heterosexual YAs; and 3) identify mediators and moderators of the impact of parenting behaviors on tobacco use behaviors among sexual minority versus heterosexual YAs. The proposed research leverages a developmental framework, sociocognitive theory and minority stress theory, and multiple research methods, including a 1-year longitudinal survey design and qualitative interviews. Ultimately, this proposal will advance a high-impact career of a promising young investigator and inform family-based interventions to reduce...