title: The difference between HIV and syphilis prevalence and incidence cases: results from a cohort study in Nanjing, China, 2008-2010.
abstract: The available estimates of incidence and prevalence of syphilis among men who have sex with men (MSM) in Mainland China are high. We used respondent-driven sampling to recruit MSM in the study population. The participants were followed up to monitor the incidence and change of risk behaviours. A face-to-face interview was used to collect information about high-risk behaviours, demographics and recreational drug use. To test the difference between prevalent and incident cases, two nested matched case-control studies were carried out. The cases were the HIV or syphilis positives found at baseline and during follow-up. We used density sampling to sample six controls for each case. Our results indicate that compared to incident cases, prevalent cases had a higher proportion of reported unprotected anal intercourse for both HIV and syphilis. Regression analysis indicated that unprotected anal intercourse was the main risk factor among HIV-prevalent cases but not in HIV-incident cases. These differences could possibly be explained by the implementation of the risk reduction interventions. Syphilis was not a risk factor for HIV-prevalent cases but was highly associated with HIV-incident cases. Tailored interventions addressing unprotected anal intercourse and other risk factors can help to reduce the prevalence and incidence of HIV and syphilis.
authors.affiliation: University of North Carolina Project-China, Guangzhou, China.
authors.forename: Weiming
authors.initials: W
authors.lastname: Tang
authors.affiliation: Public Health Foundation of India, IIPH-H wing, Bangalore, India.
authors.forename: Giridhara R
authors.initials: GR
authors.lastname: Babu
authors.affiliation: Jiangsu Provincial Central for Disease Control and Prevention, Nanjing, Jiangsu, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.affiliation: University of North Carolina Project-China, Guangzhou, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Provincial Central for Disease Control and Prevention, Nanjing, Jiangsu, China.
authors.forename: Gengfeng
authors.initials: G
authors.lastname: Fu
authors.affiliation: Jiangsu Provincial Central for Disease Control and Prevention, Nanjing, Jiangsu, China.
authors.forename: Xiping
authors.initials: X
authors.lastname: Huan
authors.affiliation: Jiangsu Provincial Central for Disease Control and Prevention, Nanjing, Jiangsu, China.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tucker
authors.affiliation: Monitoring and Evaluation Unit, The Global Fund to Fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland Jinkou.Zhao@theglobalfund.org.
authors.forename: Jinkou
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Epidemiology, University of California, Los Angeles, CA, USA.
authors.forename: Roger
authors.initials: R
authors.lastname: Detels
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005500:Follow-Up Studies; D015658:HIV Infections / Q000453:epidemiology*; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012044:Regression Analysis; D012307:Risk Factors; D012309:Risk-Taking; D012747:Sexual Partners; D019966:Substance-Related Disorders / Q000453:epidemiology; D013587:Syphilis / Q000453:epidemiology*; D047568:Unsafe Sex / Q000706:statistics & numerical data*
keywords: AIDS; Asia; HIV; MSM; epidemiology; incidence; location; men who have sex with men; risk factors; sexual behaviour; sexually transmitted infection; viral disease