title: [Incidence and risk factors of HIV and syphilis seroconversion among men who have sex with men in Beijing].
abstract: OBJECTIVE
  To study the incidence and risk factors of HIV and syphilis seroconversion among men who have sex with men (MSM) in Beijing.
  
  
  METHODS
  A total of 550 MSM were recruited on the basis of community and followed up after 6 and 12 months in Beijing. Each subject was investigated by only one investigator at one time to collect information on demographics and behaviors. Blood samples were collected to test HIV and syphilis seroconversion. ELISA was used for screening test, west blotting (WB) and Particle agglutination were used for confirmatory test.
  
  
  RESULTS
  A total of 550 MSM investigated, among which 4.5% (25/550) were HIV-positive and 29.3% (161/550) were syphilis-positive. For 525 HIV-negative MSM, 87.0% (457/525) retained during the 12-month investigation. Seroincidence for HIV and syphilis were 3.37/100 person-years (95%CI = 1.66 - 5.08) and 9.32/100 person-years (95%CI = 5.87 - 12.77) respectively. HIV seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 7.11/100 and 0.76/100 person-years respectively. Multivariate Cox regression analysis revealed that rectal douching after homosexual anal intercourse in the past 3 months (HR = 9.23, 95%CI = 2.08 - 40.88) was significantly associated with HIV seroconversion. Syphilis seroconversions for those who met male sex partners in parks, public washrooms or bathhouses in the past 3 months were 41.77/100 and 7.97/100 person-years respectively. Syphilis seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 16.17/100 and 4.92/100 person-years respectively. In the past 3 months, meeting male sex partners in parks, public washrooms or bathhouses (HR = 4.67, 95%CI = 1.77 - 12.34) and performing rectal douching after homosexual anal intercourse (HR = 3.09, 95%CI = 1.40 - 6.83) were significantly associated with syphilis seroconversion.
  
  
  CONCLUSIONS
  The seroconversions of HIV and syphilis during the follow-up visits in this MSM cohort study in Beijing were very serious, and that the associated factors for seroconversions were rectal douching after homosexual anal intercourse and meeting male sex partners in parks, public washrooms or bathhouses.
authors.affiliation: Beijing Chaoyang District Center for Disease Control and Prevention, Beijing 100021, China.
authors.forename: Shu-ming
authors.initials: SM
authors.lastname: Li
authors.forename: Zhen-hai
authors.initials: ZH
authors.lastname: Zhou
authors.forename: Shu-lin
authors.initials: SL
authors.lastname: Jiang
authors.forename: Ying-jie
authors.initials: YJ
authors.lastname: Liu
authors.forename: Dong-liang
authors.initials: DL
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiao-xi
authors.initials: XX
authors.lastname: Zhang
authors.forename: Feng-ji
authors.initials: FJ
authors.lastname: Luo
authors.forename: Yu-hua
authors.initials: YH
authors.lastname: Ruan
authors.forename: Yi-ming
authors.initials: YM
authors.lastname: Shao
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D002681:China / Q000453:epidemiology; D006678:HIV / Q000276:immunology; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology; D006679:HIV Seropositivity / Q000097:blood / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D012725:Sexual Behavior; D013587:Syphilis / Q000097:blood* / Q000453:epidemiology; D014210:Treponema pallidum / Q000276:immunology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D015483:HIV Antibodies