Moderating effect of illicit drug use on the relationship between sexual behaviours and prevalence of HIV or sexually transmitted infections

Introduction and Aims: We aimed to: (i) investigate sexual behaviours, substance use, HIV and sexually transmitted infections (STI) prevalence among a population of men who have sex with men (MSM) in Taiwan; and (ii) examine the moderating effects of substance use in the relationship of sexual behaviours and HIV and STI diagnosis. Design and Methods: We used the Taiwan 2013 Internet MSM Sex Survey conducted cross-sectionally online. We examined the association between sexual behaviours and HIV and STIs using logistic regression models. We then assessed the moderating effects of substance use between specific sexual behaviours and HIV and STI using interaction term. Results: Among the 2020 MSM participants, 5.5% of them had reported having been diagnosed with HIV and 7.4% with STIs. Reporting having a sex partner found online, having unprotected anal sex with a casual male partner, alcohol and illicit drug use were all significantly associated with HIV and STI diagnosis. Those reporting having sex with partners found via mobile apps were more likely to report being HIV positive as a function of illicit drug use. A similar finding was evident for STIs. Interestingly, alcohol had no moderating effects in similar analyses. Discussion and Conclusions: This study sheds light on future development of interventions that target at mobile apps which better integrate drug prevention and HIV prevention programs for the MSM population.