The relationship between methamphetamine and popper use and risk of HIV seroconversion in the multicenter AIDS cohort study.

Background: The association between methamphetamine use and HIV seroconversion for men who have sex with men (MSM) was examined using longitudinal data from the Multicenter AIDS Cohort Study.

Methods: Seronegative (n = 4003) men enrolled in 1984 to 1985, 1987 to 1991, and 2001 to 2003 were identified. Recent methamphetamine and popper use was determined at the current or previous visit. Time to HIV seroconversion was the outcome of interest. Covariates included race/ethnicity, cohort, study site, educational level, number of sexual partners, number of unprotected insertive anal sexual partners, number of unprotected receptive anal sexual partners, insertive rimming, cocaine use at the current or last visit, ecstasy use at the current or last visit, any needle use since the last visit, Center for Epidemiologic Study of Depression symptom checklist score >16 since the last visit, and alcohol consumption.

Results: After adjusting for covariates, there was a 1.46 (95% confidence interval [CI]: 1.12 to 1.92) increased relative hazard of HIV seroconversion associated with methamphetamine use. The relative hazard associated with popper use was 2.10 (95% CI: 1.63 to 2.70). The relative hazard of HIV seroconversion increased with the number of unprotected receptive anal sexual partners, ranging from 1.87 (95% CI: 1.40 to 2.51) for 1 partner to 9.32 (95% CI: 6.21 to 13.98) for 5+ partners. The joint relative hazard for methamphetamine and popper use was 3.05 (95% CI: 2.12 to 4.37). There was a significant joint relative hazard for methamphetamine use and number of unprotected receptive anal sexual partners of 2.71 (95% CI: 1.81 to 4.04) for men with 1 unprotected receptive anal sexual partner, which increased in a dose-dependent manner for >1 partners.

Conclusions: Further examination of the mechanisms underlying the synergism of drug use and sexual risk behaviors on rates of HIV seroconversion is necessary for the development of new targeted HIV prevention strategies for non-monogamous drug-using MSM.