Behavioral surveillance of heterosexual exchange-sex partnerships in San Francisco: context, predictors and implications.

Using San Francisco local data from the 2006 National HIV Behavioral Surveillance (NHBS), we initiated a study of male and female heterosexuals' involvement in exchange sex (money or goods for sex). We examined risk factors for engaging in exchange sex and the prevalence of risk behaviors amongst exchange and non-exchange partnerships. Overall, 13.2% of women and 7.6% of men engaged in exchange sex in the past 6 months; 130 of 1,230 (10.6%) opposite-sex partnerships involved exchange. Women of low socioeconomic status and those who inject drugs were more likely to engage in exchange sex. Men involved in exchange sex were no different from those who did not by age, socio-economic status, marital status, drug use, or history of incarceration or sexually transmitted diseases. Within exchange partnerships, high or drunk sex was more common than unprotected sex. Exchange partnerships had fewer instances of risky sex. In comparison to exchange partnerships, non-exchange partnerships had four times as many episodes of unprotected vaginal sex and twice as many episodes of high or drunk vaginal sex. Prevention efforts addressing exchange sex need to address substance use. Future research and surveillance are needed to better understand the sources of HIV risk and measure and track trends in risk within sexual dyads and networks.