Anal sex among HIV-seronegative women at high risk of HIV exposure

To assess the prevalence and the sociodemographic and behavioral correlates of anal sex in a cohort of HIV-seronegative U.S. women at high risk of HIV exposure, we administered a risk assessment using audio computer-assisted self-interview (A-CASI). Of 1268 sexually active women, 432 (32%) reported anal sex in the previous 6 months. Compared with women who did not report a nal sex, those who did had more unprotected vaginal sex (median of 11 versu s 7 episodes; p < .001) and a higher proportion of unprotected sexual (vagi nal plus anal) episodes (median of 0.90 versus 0.81; p = .01). Anal sex was reported by higher proportions of women who did not always use condoms, wh o used crack in the past year, who were less than or equal to 35 years of a ge, with no formal education beyond high school, who had had a diagnosed se xually transmitted disease in the previous year, a primary male sex partner , and a male sex partner with a history of injecting use. Women were more l ikely to report anal sex by A-CASI than during interviewer-administered ris k assessments (odds ratio [OR], 9.00; 95% confidence interval [CI], 1.14-71 .0). A less biased method of ascertainment may account for the large propor tion of women reporting anal sex. Given increased vaginal risk among women reporting anal sex, the relative importance of anal sex in heterosexual tra nsmission merits further study. Behavioral and biomedical prevention strate gies effective for anal as well as vaginal sex are needed.