UNSAFE SEX IN MEN WHO HAVE SEX WITH BOTH MEN AND WOMEN

The sexual behaviors of bisexually active men, defined as men having s ex with a man and a woman in previous 6 months, were compared with men who had sex with men only. Differential sexual practices associated w ith HIV risk between the two groups of men, as well as in the bisexual men with their male and female partners, were evaluated. Cross-sectio nal analyses were performed on baseline data from a prospective cohort of 508 young gay men recruited from bars, college campuses, and a hea lth center in Boston from 1993 to 1994. Odds ratios (OR) and 95% confi dence intervals (CI) were calculated on categorical variables, and McN emar's X-2 was used to compare the behaviors of bisexual men with thei r male versus female sex partners. Six months before the interview, 47 (10%) men had male and female sex partners, and 383 men had only male sex partners during the past year or ever. Fifty-eight percent of the men in the study had a female sexual partner in their lifetime, and 1 8% during the past year. Bisexual men were more likely to have drinkin g problems as identified by the Michigan Alcoholism Screening Test (MA ST; OR = 3.96, 95% CI = 1.54-10.20), and fewer male partners over thei r lifetime (mean +/- standard deviation [SD], 24 +/- 42; median, 7; ve rsus mean +/- SD, 69 +/- 516; median, 12), although this difference wa s not statistically significant. The two groups had similar levels of unprotected anal intercourse (25.5% versus 29.5%); however, bisexual m en were half as likely to have anal sex as homosexual men (OR = 0.50; 95% CI = 0.27-0.93). Bisexual men were three times as likely to have u nprotected sex with their female partner as their male partner (OR = 3 .0; 95% CI = 1.02-8.8). Stratified analysis revealed similar discordan t behavior while sober (OR = 4.0), drinking (OR = 7.0), and while drin king with concurrent drug use (OR = 8.0). Among this cohort of men who have sex with men (MSM), a sizable proportion also had vaginal sex wi th female partners in the previous 6 months. Bisexually active men wer e more likely to have unprotected sex with their female partners compa red with their male partners, potentially increasing the risk for HIV and other sexually transmitted diseases. Behavioral interventions dire cted toward MSM need to address bisexual behaviors.