Studies of incidence, prevalence and risk factors for HIV infection in special populations of men who have sex with men: Los Angeles, 1993--2002

Since the beginning of the HIV epidemic in Los Angeles County (LAC), HIV infection has affected primarily men who acquired the virus through sex with male partners. Given the disproportionate burden of HIV/AIDS experienced by MSM, especially for MSM of color, this dissertation focuses on estimating incidence, prevalence and risk factors for HIV in this population.;The first paper in this dissertation investigates the rate of new infection among MSM clients of STD clinics in Los Angeles. I conducted a practical comparison of a novel method, the Serological Testing Algorithm for Recent HIV Seroconversion (STARHS), to estimate HIV incidence from a cross-sectional study population versus a medical record-based longitudinal cohort conducted during the same time period. While the first paper did not discover a new gold standard to estimate HIV incidence, it provided a practical understanding of the strengths and limitations of STARHS.;The second paper used data collected for the Young Men's Survey, a venue-based probability survey of young MSM, residing in LAC between 1999 and 2000. In addition to estimating HIV prevalence and risk factors for HIV among young MSM, I investigated the "effect" of male sexual partner characteristics hypothesized to account for black and Latino MSM's higher HIV prevalence compared to white MSM. While the results are not definitive in accounting for the increased odds of HIV infection comparing black to white MSM, they provide some suggestive evidence regarding the role of partner characteristics on HIV risk for black MSM.;The third dissertation paper is an investigation of HIV prevalence and risk factors for unprotected anal sex (UAS) in two samples of MSM attending a gay bathhouse in LAC. The main findings show that unsafe sex in other settings and higher numbers of bathhouse partners are risk factors for UAS at last bathhouse visit across patron samples. This analysis underscores the importance of providing HIV testing to bathhouse attendees for the purpose of detecting unrecognized HIV infection among a subpopulation of MSM practicing risky sexual behaviors both within and outside these settings.