UNDERSTANDING THE LINK BETWEEN ALCOHOL USE AND STIS: TWO TESTS OF MEDIATION

Background Alcohol use has been associated with STIs. This association is generally attributed to an impaired ability to appreciate future consequences, leading individuals to engage in unprotected sex after consuming alcohol. However, a second pathway through which alcohol use leads to STI is through an impaired ability to use a condom correctly. Problems related to using condoms reduce their efficacy and have been associated with incident STIs. This study investigates both unprotected sex and incorrect condom use as potential mediating pathways through which alcohol use might lead to STIs. Methods Participants (498 patients; 41% female; 69% African American) attending a publicly-funded STI clinic completed a computerised survey assessing global alcohol use (AUDIT-C), alcohol use before sex, incorrect condom use, episodes of unprotected sex, and recent STI history. Bootstrapped mediation analysis with 5000 resamples tested a multiple mediator model in which the number of episodes of unprotected sex and incorrect condom use mediated the relation between alcohol use and STI. Results Participants reported an average of 17 episodes of unprotected sex in the past 3 months; 17% reported being diagnosed with an STI in the past 3 months. Controlling for gender, inconsistent condom use mediated the relation between alcohol use before sex and STI (95% bootstrapped CI for the indirect effect = 0.002 to 0.056; p Conclusion Alcohol use before sex may increase risk for STIs due to an impaired ability to use condoms correctly, rather than through unprotected sex. Findings have implications for STI prevention because intoxication may impair effective use of condoms despite intentions to use them.