Comparison of Substance Use Typologies as Predictors of Sexual Risk Outcomes in African American Adolescent Females.

African American female adolescents have a disproportionate risk of sexually transmitted infections (STIs) and other adverse sexual health outcomes. Both alcohol and marijuana use have been shown to predict sexual risk among young African American women. However, no studies have attempted to differentiate alcohol and marijuana typologies use as predictors of sexual risk outcomes exclusively among adolescents who use these substances. This study compared recent alcohol and/or marijuana use as predictors of sexual risk outcomes over 18 months among 182 African American female adolescents. African American females (14-20 years) completed interviews at baseline, 6-, 12-, and 18-months. At each assessment, pregnancy testing was conducted and self-collected vaginal swab specimens were assayed for Trichomonas vaginalis, Chlamydia trachomatis, and Neisseria gonorrhoeae using DNA amplification. Logistic subject-specific random-intercept models compared sexual risk outcomes during follow-up among adolescents who reported recent use of alcohol only (AO), marijuana only (MO) or both substances (A + M) at the baseline assessment. Relative to baseline AO use, baseline MO use predicted condom non-use at last sex. Relative to AO use, A + M use predicted pregnancy. Relative to MO use, A + M use predicted pregnancy and acquisition of T. vaginalis and any STI. The results suggest that African American female adolescents who use A + M may represent a priority population for STI, HIV, and pregnancy prevention efforts.