ABSTRACT
<p><b>OBJECTIVES</b>To investigate the incidence of syphilis infection and to determine the risk factors related to syphilis infection among young men who had sex with men (YMSM), which were documented for developing effective intervention to prevent sexually transmitted diseases among YMSM.</p><p><b>METHODS</b>A cohort study was conducted in 8 cities (Beijing, Shanghai, Kunming,Guiyang, Chongqing, Chengdu, Urumqi and Nanning) from May to December, 2009. A total of 1 037 syphilis-negative YMSM aged 18-25 were enrolled in the cohort and the two follow-up surveys were carried out every six months. The contents of study included sociodemographic characteristics, HIV-related knowledge, sexual behavior and condom use in the 6 months prior to survey. All participants were tested for syphilis with whole blood specimens. Chi-square test was used to compare demographic characteristics of participants in baseline with those of two follow-up, and Cox regression analysis was used to identify risk factors associated with syphilis infection.</p><p><b>RESULTS</b>The rates of participants in 6, 12 months follow-up surveys was 79.85% (828/1 037) and 82.16% (852/1 037) respectively.39 syphilis seroconversions were found in the 12 months follow-up survey. Cumulative observed person-years during follow-up time was 1 106.67. The syphilis incidence rate was 3.5%. The Multivariate Cox regression analysis showed that the education of senior high school (senior high school vs some college or higher, RR = 2.19, 95% CI:1.21-3.98), bisexual orientation (bisexual orientation vs homosexual orientation, RR = 2.19, 95% CI:1.21-3.97), score of HIV/AIDS knowledge <8 (score of HIV/AIDS knowledge <8 vs knowledge = 8, RR = 2.39, 95%CI:1.35-4.21), had two and more sexual partners and inconsistent condom use in the past 6 months (inconsistent condom use vs consistent condom use, RR = 3.10, 95% CI:1.39-6.91) were significantly associated with syphilis seroconversion in the 12-month period.</p><p><b>CONCLUSIONS</b>The syphilis incidence was high and risk behaviors were common among YMSM of China.</p>