title: The influence of social and sexual networks in the spread of HIV and syphilis among men who have sex with men in Shanghai, China.
abstract: OBJECTIVE
  To analyze characteristics of social and sexual networks and their role as risk factors for HIV and syphilis among men who have sex with men (MSM) in Shanghai, China.
  
  
  METHODS
  : A cross-sectional study.
  
  
  METHODS
  We recruited 477 participants using a snowball sampling method. We administered a face-to-face questionnaire and provided testing and counseling for HIV and syphilis.
  
  
  RESULTS
  The prevalences of HIV and markers for syphilis were 1.47% (95% confidence interval [CI]: 0.59 to 3.01) and 13.47% (95% CI: 10.53 to 16.88), respectively. The independent factors associated with lower risk for syphilis infection were having a contact network, overlap of social and sexual networks, meeting other MSM at the gym or through the Internet, having 3 to 5 lifetime male anal sex partners, and having a female steady sex partner. A larger male sexual network size, having been married, being more knowledgeable about HIV, having 6 or more lifetime male anal sex partners, and having steady male or female sex partners were independently associated with having unprotected anal or vaginal intercourse.
  
  
  CONCLUSIONS
  Significant associations were found between network characteristics and syphilis infection and unprotected sex. Network-based interventions should be developed to reduce this HIV risk among MSM in China.
authors.affiliation: Center for AIDS Prevention Studies, University of California, San Francisco, San Francisco, CA 94105, USA. kyung-hee.choi@ucsf.edu
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Choi
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ning
authors.forename: Steven E
authors.initials: SE
authors.lastname: Gregorich
authors.forename: Qi-Chao
authors.initials: QC
authors.lastname: Pan
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002681:China / Q000453:epidemiology; D002947:Cities; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012725:Sexual Behavior; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000453:epidemiology; D012944:Social Support; D011795:Surveys and Questionnaires; D013587:Syphilis / Q000453:epidemiology / Q000635:transmission*; D014505:Urban Population
chemical_list: D015415:Biomarkers