HIV incidence and associated factors in a cohort of men who have sex with men in Nanjing, China.

BACKGROUND

Many surveys conducted in recent years reported the increasing trend of HIV infection among men who have sex with men (MSM), but limited data exists on HIV incidence by cohort study in China.

METHODS

A 6-month prospective cohort study was conducted. A total of 397 MSM found HIV seronegative at baseline study were followed-up for 6 months starting from May 2007 and re-evaluated seroconversions of HIV at 6 months. Questionnaire interviews were conducted to collect information about risk behaviors.

RESULTS

Of the 397 MSM who were found seronegative at the baseline study, 286 (72.0%) received the HIV antibody testing at month 6; 7 of them showed HIV seroconversions, yielding an incidence of 5.12 per 100 person-years. Significant predictors of seroconversion (Poisson regression analyses) included duration being MSM >10 years (relative risks [RR] = 3.08, 95% CI: 1.53-6.20), recruiting male sex partner mostly at saunas (RR = 2.35, 95% CI:1.09-5.08), positive syphilis diagnosis made at the baseline study (RR = 2.82, 95% CI: 1.31-6.09), having multiple male sex partners in the last 6 months (RR = 2.54, 95% CI: 1.18-5.49), having at least 1 casual male sex partner in the last 6 months (RR = 2.17, 95% CI: 1.00-4.70), and having unprotected anal sex with a regular male sex partner in the last 6 months (RR = 2.22, 95% CI: 1.10-4.49).

CONCLUSIONS

The incidence of HIV among MSM is very high; many new infections would hence occur in China. Effective interventions are warranted. The risk factors reported in this study give some insights for designing relevant prevention programs.