Anal intercourse and HIV risk among low-income heterosexual women: findings from Chicago HIV behavioral surveillance.

Background: Anal intercourse (AI) is a highly efficient route for HIV transmission and has not been well elucidated among heterosexual (HET) women. Heterosexual women living in impoverished urban areas in the US are at increased risk for HIV acquisition. We aim to describe rates of AI and characteristics associated with AI among heterosexual women at increased risk for HIV acquisition living 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). Eligible participants were interviewed anonymously and offered a HIV test.

Results: In total, 407 heterosexual women were interviewed. Seventy-one (17%) women reported having AI in the past 12 months, with 61 of the 71 (86%) reporting unprotected AI. In multivariate analysis, women who engaged in AI were more than three times as likely to have three or more sex partners in the past 12 months (OR=3.27, 95% CI 1.53-6.99). AI was also independently associated with STI diagnosis in the past 12 months (2.13, 95% CI 1.06-4.26), and having sexual intercourse for the first time before the age of 15 years (2.23, 95% CI 1.28-3.89).

Conclusion: AI was associated with multiple high risk behaviors including a greater number of sexual partners, STI diagnosis, and earlier age at first sex. The combination of risk factors found to be associated with AI call for new HIV prevention services tailored to the needs of women and young girls living in poverty.