Risk factors for HIV infection among men who have sex with men.

Objectives: Risk factors for HIV acquisition were examined in a recent cohort of men who have sex with men (MSM).

Design: A longitudinal analysis of 4295 HIV-negative MSM enrolled in a randomized behavioral intervention trial conducted in six US cities.

Methods: MSM were enrolled and assessed for HIV infection and risk behaviors semi-annually, up to 48 months.

Age-Specific prevalence of anal human papillomavirus infection in HIV-negative sexually active men who have sex with men: the EXPLORE study.

Background: In the United States, anal cancer in men who have sex with men (MSM) is more common than cervical cancer in women. Human papillomavirus (HPV) is causally linked to the development of anal and cervical cancer. In women, cervical HPV infection peaks early and decreases after the age of 30.