[HIV infections and heterosexual behaviors among men who have sex with men in Chongqing municipality, China].

OBJECTIVE: To understand the prevalence and risk factors for both HIV infection and prevalence rates of syphilis infection among men who exclusively have sex with men (MSM/M) or with both men and women (MSM/W) in Chongqing municipality, China.

METHODS: Cross-sectional studies were conducted in Chongqing. Structured questionnaire-based interviews were conducted to provide information about demographic characteristics, behavior, HIV related health services and sexual transmitted infections (STIs). Blood samples were tested for HIV and syphilis infections.

RESULTS: Of 1691 participants, 21.6% were MSM/W, with HIV prevalence as 16.1% which was significantly higher than that among MSM/M (9.4%, P < 0.001). Factors independently associated with HIV infection among MSM/W included being separated/divorced/widowed (AOR = 14.8, 95%CI: 3.1 - 71.6), having multiple male sex partners (AOR = 5.4, 95%CI: 1.8 - 16.3), unprotected anal sex behaviors (AOR = 4.6, 95%CI: 1.5 - 13.9) and syphilis infection (AOR = 4.4, 95%CI: 1.1 - 17.3). Factors independently associated with HIV infection among MSM/M were as follows: lower education (AOR = 2.6, 95%CI: 1.6 - 4.5), older age (AOR = 2.0, 95%CI: 1.3 - 3.3, 26 - 35 years vs. < 26 years; AOR = 1.9, 95%CI: 1.1 - 3.5, > 35 years vs. < 26 years), being recruited from bath house/sauna (AOR = 2.5, 95%CI: 1.1 approximately 5.6) syphilis infection (AOR = 1.9, 95%CI: 1.0 - 3.4), multiple male sex partners (AOR = 1.8, 95%CI: 1.1 - 2.9), and STIs infection (AOR = 1.7, 95%CI: 1.0 - 2.7). Heterosexual behaviors independently associated with married/cohabiting (AOR = 6.5, 95%CI: 4.4 - 9.8), self-identified as bisexual/heterosexual (AOR = 3.9, 95%CI: 2.8 - 5.5), first lifetime female sex partners (AOR = 2.2, 95%CI: 1.5 - 3.0), lack of HIV related knowledge (AOR = 1.9, 95%CI: 1.1 - 3.2), being recruited from bars/night clubs/tea bars (AOR = 1.6, 95%CI: 1.0 - 2.6), older age at sex debut (AOR = 0.6, 95%CI: 0.4 - 0.8), not offering sex for money for anal intercourses in the past six months (AOR = 0.5, 95%CI: 0.3 - 1.0) and HIV infection (AOR = 1.7, 95%CI: 1.1 - 2.7).

CONCLUSION: HIV prevalence had reached a high level among men who have sex with men and women in Chongqing, China. Multiple sex partners and other high risk behaviors when having sex with men or women among MSM/W represented a unique risk group within the population of MSM that might have bridged the HIV transmission between HIV high risk group and general population. More attention need to be specifically paid to prevent HIV transmit from HIV high risk group to general population.