Sexual behavior patterns and HIV risks in bisexual men compared to exclusively heterosexual and homosexual men

Objective. To compare patterns of sexual behavior among bisexual, heterosexual and homosexual men. Material and Methods. A household probability survey was carried out in Mexico City in 1992-1993 using the national health surveys sampling frame. Information from 8 068 men was obtained; however, the main analysis of this paper refers only to men sexually active in the previous 5 years. Results. Bisexuals reported more prevalent anal intercourse with women (16% vs. 3%, p=0.01), and more sexual encounters with female sex workers than exclusive heterosexuals (10% vs. 4%; p=0.04). Bisexuals used condoms more often with sex workers than did heterosexuals (p=0.01). Most of the bisexuals (79%) did not engage in anal receptive or insertive intercourse with males in the previous year, practicing instead oral insertive sex or only masturbation; 35% of homosexuals did not report practicing anal sex. Bisexuals who engaged in anal intercourse had less anal receptive behavior than homosexuals (13% vs. 60%, p<0.01); of these, due to condom use, only 7% of bisexuals and 18% of homosexuals had unprotected anal receptive sex in the last intercourse with a male. Conclusions. Bisexuals practice less risky sexual behavior with males than exclusive homosexuals. This finding may imply that bisexual men in Mexico are an ineffective epidemiological bridge for HIV transmission. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.