PrEP Intentions, Heavy Substance Use, and Gender Affirmation among Black and Latine Transgender and Gender-Expansive Youth: A Structural Equation Modeling Analysis.

Black and Latine transgender/gender-expansive youth/emerging adults ages 13-24 years, experience disproportionate HIV risk, yet have the lowest PrEP uptake rates in the U.S. (< 8%). This study examines the effects of gender-minority stressors, gender affirmation, and heavy substance use on their PrEP outcomes using data from the CDC's 2018 START study (N = 423). We used structural equation modeling (Mplus v. 8.10) to examine factors related to their PrEP intentions using our newly developed conceptual model. The majority of participants were 18-24 (77.3%), transfemale (69.7%), Latine (63.1%), and reported heavy substance use behaviors (50.6%). Family rejection increased perceived stigma (b = 0.209, SE = 0.050, p < 0.001) and heavy substance use behaviors (b = 0.356, SE = 0.072, p < 0.001). Perceived stigma also increased heavy substance use behaviors (b = 0.084, SE = 0.041, p 0.041). Additionaly, heavy substance use decreased PrEP intentions (b = -0.160, SE = 0.049, p < 0.001), while gender affirmation increased PrEP intentions (b = 0.087, SE = 0.030, p < 0.004). When family rejection was present, for each 1-point increase in gender affirmation, the risk of heavy substance use was reduced by -0.197 (SE = 0.038; p < 0.001). This study identifies heavy substance use as a potential barrier to PrEP uptake among Black and Latine transgender and gender-expansive youth, given its significant negative association with PrEP intentions. Findings highlight the need for strategies to improve PrEP outcomes, underscoring the importance of operationalizing gender affirmation across settings, particularly amid family rejection and heavy substance use.