Moderating effects of age on the alcohol and sexual risk taking association: an online daily diary study of men who have sex with men.

Men who have sex with men (MSM) account for the majority of HIV/AIDS diagnoses and data suggest infection rates are rising. Identification of factors that increase the risk of infection is key to the development of effective prevention programs. Previous research has been inconsistent regarding the link between alcohol consumption and sexual risk taking among MSM. Daily reports of alcohol consumption and sexual behavior were completed for up to 30 days by 143 HIV negative MSM recruited online. This resulted in 2,887 daily reports of number of sex partners and 549 episodes of sex. Independent variables included age, number of standard drinks consumed, and partner type. Outcome variables included sex with a partner, a composite sexual risk variable, and unprotected anal intercourse (UAI). Alcohol consumption significantly increased the odds of having sex and had a significant positive association with the sexual risk composite variable. Age was a significant moderator of the association between alcohol consumption and sexual risk taking, with the effects of alcohol increasing with age. For example, at the 75%tile of age (37 years old), the odds of UAI increase from approximately 0.2 to 0.35 as the number of alcoholic drinks increases from zero to seven. Partner type did not have significant effects. Daily reports of alcohol consumption had a significant within-person association with sexual risk behaviors, particularly among older MSM. Findings highlight the importance of measuring individual differences as moderators of the association between alcohol and risky sexual behavior.