UCLA

Background: We explored the effect of older partner’s age and age difference between partners on condomless sex among MSM.

Methods: We analyzed data from the Sexual Acquisition Transmission of HIV Cooperative Agreement Program. We used modified Poisson regression to model the probability of a sexual encounter’s being condomless as function of HIV status, substance use, older partner’s age, age difference between partners, and race/ethnicity.

Results: We found an interaction between older partner’s age and age difference (p<0.05). Condomless sex decreased with increasing age when age difference was 5-9 years (p=0.005) or ≥ 10 years (p=0.05), but not when the age difference was <5 years (p=0.4). When the age difference is 5-9 years, 40% of encounters are condomless if the older partner is 32 years old, but only 23% are condomless if 54 years old.

Conclusion: Both age and age discordance play important roles in the likelihood of a sexual encounter between MSM being condomless.