Anal intercourse and HIV risk among heterosexual women in Chicago

Background: Unprotected AI is a highly efficient route for HIV transmission and has not been well elucidated among heterosexual women. We aim to describe rates of anal intercourse (AI) and characteristics associated with AI among at-risk heterosexual women in Chicago. Methods: The Chicago Department of Public Health conducted a survey of HET during 2007 as part of the National HIV Behavioral Surveillance System. Venue-based, time-location sampling was used to select participants from venues in high-risk areas (census tracts with concurrently high rates of heterosexual AIDS and household poverty). Venues included convenience stores, laundromats, and beauty salons, etc. Eligible participants were interviewed and offered a HIV test. Results: In total, 412 heterosexual women were interviewed. Seventy-four (18%) women reported having AI in the past 12 months, with 64 of the 74 (86%) reporting unprotected AI. Women who engaged in AI were three times more likely to engage in unprotected vaginal intercourse with a casual partner (OR=2.94, 95%CI 1.67-5.18). Engaging in AI was also found to be associated with: homelessness (3.18, 1.76-5.73), incarceration (2.73, 1.40-5.32), exchange sex (4.27, 2.05-8.87), non-injection drug use (2.69, 1.61-4.53), and a recent STI diagnosis (3.18, 1.76-5.73). Conclusion: A significant proportion of heterosexual women at-risk for HIV in Chicago engage in anal sex. Its strong association with unprotected vaginal sex and other social factors reveals a profound level of vulnerability beyond the general challenges of urban poverty. Better understanding of the synergy between anal intercourse, social instability and HIV risk could enhance HIV prevention and health promotion efforts.