Middle-aged and older men who have sex with men exhibit multiple trajectories with respect to the number of sexual partners.

This study aimed to examine trajectories with respect to the number of sexual partners among older men who have sex with men and to determine characteristics associated with trajectory groups. Nagin's group-based modeling was used to identify trajectories for 237 men from the Pitt Men's Study with respect to the number of male intercourse partners from age 50.0 to 59.5. Three distinct trajectory groups were identified. Most men (69.2%) had a median of two sexual partners in the past 6 months across the age range of the study. A smaller group (19.4%) had low or no sex partners. The smallest group (11.4%) had 30 or more sexual partners in the past 6 months at age 50. The groups were statistically different with respect to race, HIV status, drug use (marijuana, poppers, crack cocaine, and Viagra), the number of unprotected anal sex partners, and personal attitudes towards sex.