Alcohol use and high-risk sexual behavior among men who have sex with men: the effects of consumption level and partner type.

Alcohol use may increase HIV sexual risk behavior, although findings have varied across study populations and methods. Using event-level data from 1,712 seronegative men who have sex with men, the authors tested the hypothesis that social context would moderate the effect of alcohol consumption on unprotected anal sex (UAS). For encounters involving a primary partner, rates of UAS did not vary as a function of alcohol use. However, consumption of 4 or more drinks tripled the likelihood of UAS for episodes involving a nonprimary partner. Thus, the effects of alcohol vary according to the context in which it is used. Interventions to reduce substance-related risk should be tailored to the demands of maintaining sexual safety with nonprimary partners.