Sex with older partners is associated with primary HIV infection among men who have sex with men in North Carolina

Abstract

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.

Figure 1. Respondent-driven sampling and structure of the SNAP sexual network

(A) Each seed participant (dark gray) recruited three sexual partners (solid lines), who in turn recruited three sexual partners of their own – creating two generations for the study. (B) The two largest components of the sexual network had 9 participants each; one had a three-core (the closed, four-vertex “loop” of the upper component). Of five dyads, only one involved men with PHI (thick black line). Not shown are 18 PHI and 25 HIV-uninfected participants who did not recruit any eligible participants.

Figure 2. Distribution of differences between ages of individual sex partners and their associated seed participant

Depicted are 60 sex partners of MSM with primary HIV infection (PHI) and 162 partners of HIV-uninfected participants. We noted a broader distribution of ages among partners of the MSM with PHI, while HIV-uninfected participants more often had partners very close to their own age.

Figure 3. Odds of primary HIV infection (PHI) increase as sex partner age increases

After adjusting for nonwhite race, sex while intoxicated, and having a serodiscordant or serostatus unknown (SD/SU) partner, having sex with a partner 5 years older than the participant doubled the odds of PHI (OR 2.2, 95% CI, 1.2, 3.3), while a partner 10 years older quadrupled the odds (OR 4.1, 95% CI, 1.5, 11).