Background: Studies from the 1990s suggested sex with older partners was associated with HIV infection. We evaluated the hypothesized association between primary HIV infection (PHI) and having older sexual partners among men who have sex with men (MSM).
Methods: MSM with PHI and HIV-uninfected MSM completed audio computer-assisted self-interviews exploring behaviors involving their 3 most recent sexual partners before enrollment (if uninfected) or diagnosis (if PHI).
Results: Of 74 men reporting any lifetime sex with men, 20 had PHI (27%). Demographics (including age) were similar between groups; 39% were non-white and 74% identified as gay. The mean age of sex partners differed significantly: men with PHI had partners on average 6 years older than themselves, whereas uninfected men's partners were 4 months their junior (P < 0.001). After adjusting for race, sex while intoxicated, and having a serodiscordant/serostatus unknown partner, a participant had twice the odds of PHI if his sex partner was 5 years his senior (odds ratio 2.0, 95% confidence interval: 1.2 to 3.3).
Conclusions: Among a sample of young MSM, the odds of HIV infection increased significantly as the age of sexual partners increased. These findings can inform behavioral interventions in communities of at-risk MSM and secondary prevention efforts among those already living with HIV.