Prevalence and associated risk characteristics of HIV infection based on anal sexual role among men who have sex with men: a multi-city cross-sectional study in Western China

BACKGROUND: The HIV prevalence among men who have sex with men (MSM) in Western China is substantial and increasing at an alarming rate. The current HIV infection prevalence among MSM in Western China and its associated risk characteristics were explored by looking at different anal sexual roles separately. METHODS: A total 1245 MSM recruited by convenience sampling from multiple sources and areas in the Chongqing and Sichuan region were interviewed using an anonymous self-administered questionnaire with the assistance of investigators and then underwent HIV testing. Multivariate logistic regression was used to identify factors independently associated with HIV infection. RESULTS: Of the 1235 respondents who reported their sexual roles during anal sex with men, the overall HIV antibody positive rate was 21.21% (262/1235). With regard to the different anal sex roles, HIV-positive rates were significantly higher among men who played the '0.5' role (versatile, equal) and '0' role (only bottom or versatile, but mostly bottom) during anal sex with men than among those who played the '1' role (only top or versatile, but mostly top) (26.41% for '0.5' role, 26.20% for '0' role, and 15.19% for '1' role; Chi-square=22.66, p<0.0001). Statistically significant differences were not found between the '0.5' role and '0' role groups (p > 0.05). The '1' role MSM who had an education level lower than senior high school, a rural household registration, and low self-perceived severity status of AIDS, the '0.5' role MSM who had an education level lower than senior high school and had not undergone HIV testing in the recent 1 year, and the '0' role MSM who were retired or unemployed and had been diagnosed with a sexually transmitted disease by a doctor in the recent 6 months were more likely to be HIV-infected. CONCLUSIONS: In this study, the HIV prevalence among MSM was alarmingly high. Moreover, the '0.5' and '0' role MSM were found to have a higher risk of infection compared to the '1' role MSM, while respective risk characteristics were not completely the same across the three groups. Along with routine preventive intervention services, more focused and specific interventions are needed to target anal sex role classes separately.