Heavy Drinking, Multiple Partners Double HIV Risk in MSM of USA
Heavy drinking plus having more than 1 unprotected receptive anal intercourse partner in the past 2 years doubled the risk of HIV acquisition in a group of US men who have sex with men (MSM). Heavy drinking alone raised the risk of HIV infection 60%.
Unprotected (condom-free) receptive anal intercourse raises the risk of HIV acquisition. The impact of heavy drinking on HIV acquisition—with or without unprotected receptive anal intercourse—is not well understood.To address these issues, Multicenter AIDS Cohort Study (MACS) investigators studied 3725 HIV-negative men enrolled in the cohort from 1984 to 2008. Men self-reported drinking habits and number of unprotected receptive anal intercourse partners. The researchers used marginal structural models accounting for relevant risk factors to estimate the joint impact of drinking and number of partners on HIV acquisition.
Men reported drinking a median of 8 drinks weekly (interquartile range 2 to 16), and 30% reported multiple unprotected receptive anal intercourse partners in the past 2 years. During 35,870 person-years of follow-up, 529 men became infected with HIV.
Statistical analysis that accounted for several HIV risk factors determined that, compared with no drinking, moderate drinking of 1 to 14 drinks weekly did not significantly affect risk of HIV acquisition (adjusted hazard ratio [aHR] 1.10, 95% confidence interval [CI] 0.78 to 1.54). But compared with abstention, heavy drinking (more than 14 drinks weekly) raised the risk of HIV acquisition 61% (aHR 1.61, 95% CI 1.12 to 2.29, P < 0.001 for trend).
Among men with 0 or 1 unprotected receptive anal intercourse partner in the past 2 years, heavy drinking did not significantly affect risk of HIV acquisition (aHR 1.37, 95% CI 0.88 to 2.16). But among men with 2 or more such partners, heavy drinking doubled the risk of HIV acquisition (aHR 1.96, 95% CI 1.03 to 3.72).
The researchers believe their findings "suggest that alcohol interventions to reduce heavy drinking among men who have sex with men should be integrated into existing HIV prevention activities."
They note that "randomized interventions that explicitly address alcohol's contribution to HIV have been tested in Africa" but remain largely untried in the United States.
Source: Petra M. Sander, Stephen R. Cole, Ronald D. Stall, Lisa P. Jacobson, Joseph J. Eron, Sonia Napravnik, Bradley N. Gaynes, Lisette M. Johnson-Hill, Robert K. Bolan, David Ostrow. Joint effects of alcohol consumption and high-risk sexual behavior on HIV seroconversion among men who have sex with men. AIDS. 2013; 27: 815-825.
Written by Mark Mascolini on behalf of the International AIDS Society