Discussion. The epidemic of HIV/STD among MSM is severe, and the prevalence of risk sexual behaviors was at a high level among MSM in China. The risk factors for HIV/STD and factors associated with DAI reported in this study give some insights towards designing relevant prevention programs. The simplicity and feasibility of our effective intervention, enhanced VCT, makes it possible for this to be incorporated into standard VCT procedures. Further translational research is needed to investigate its effectiveness in the real-world setting. / Introduction. Men who have sex with men (MSM) have become the main group for HIV transmission in China in 2009. There have been many epidemiological cross-sectional studies targeting MSM in China in recent years. These provide limited data compared with cohort studies, which can describe the rate at which HIV/STD are spreading in a target population. Moreover, there is a dearth of intervention studies which are theory-based with rigorous research methodology in China. Last but not least, research is needed on sexual behaviors and their determinants, including cognitions from health behavioral theories, event-specific factors, etc. / Objectives. This study investigated the prevalence and incidence of HIV/STD, as well as their associated risk factors among MSM in Nanjing, China. It also explored the prevalence of unprotected anal sex (UAI) and the associated factors, including cognitions from health behavioral theories and event-specific factors. In addition, this is also one of the first studies to examine the efficacy of a randomized control trial (RCT) designed intervention, to use enhanced voluntary counseling and testing (VCT) to reduce UAI among MSM in China. / Results. The RDS-adjusted HIV, syphilis and HCV prevalence were respectively 7.3%, 14.4% and 0.2% at baseline. Of the 397 MSM who were found to be HIV seronegative at baseline, 286 (72.0%) retested at Month 6. HIV, syphilis and HCV incidence were respectively 5.12, 7.58 and 0 per 100 person-years (PY). Recruiting male sex partners mostly at saunas was the risk factor associated with being HIV seropositive at baseline (OR=3.84) and undergoing HIV/syphilis seroconversion at Month 6 (RR=2.351RR=6.72). In the RCT study, participants in the Intervention Group reported significantly less risk than those in the Control Group (UAI with any male sex partners: 48.4% vs. 66.7%;UAI with regular male sex partners: 52.2% vs. 68.9%) at Month 6. Furthermore, Perceived Behavior Control showed a significant association with DAI with both regular (AOR=0.42) and casual partners (AOR=O.73). / Subjects and Methods. A cohort study and randomized control trial were conducted. Out of 416 MSM approached by respondent driven sampling (RDS), 397 HIV negative participants were recruited to the HIV/syphilis/HCV cohort, and they were invited to return for a follow-up visit at Month 6. A subsample from the baseline cohort consisting of 307 MSM, was randomly assigned to either the Intervention Group (enhanced VCT) or the Control Group (standard VCT). Evaluation was conducted at Month 6. Both baseline and Month 6 visits consisted of VCT service and interviewing. Statistical methods such as Chi-square test, logistic regression and Poisson regression were used in this study. / Hao, Chun. / Adviser: Joseph TF Lan. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 166-179). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract and appendixes I-II also in Chinese.

Background A dramatic increasing trend of HIV prevalence among men who have sex with men (MSM) was observed in China from 2000. Most previous investigations were based on convenience sampling and none of them differentiated money boys (MB) from other MSMs. The objectives of this study was to determine the prevalence of HIV infection and its risk factors among MSMs in Shenzhen, China, using approximate probability sampling methods; and to interpret HIV transmission pattern among MSMs with both phylogenetical and epidemiological information. / Conclusions The prevalence of MV infection in Shenzhen MSMs was similar to the national rate in MSMs. HIV infection and related characteristics in Mf3s and other MSMs were different, indicating that a separate analysis was necessary. TLS could provide information on venue comparisons for venue-based MSMs and RDS could recruit more hidden subjects. Results from this study suggest that venue-specific intervention approaches should be developed and provided to different venues. / Results HIV prevalence was 5.5% among MSMs in Shenzhen. A significantly lower HIV infection was observed in MBs (4.5%) compared with other MSMs (7.0%). The HIV infection rate among MSMs was 5.7% by TLS and 4.6% by RDS, which were not significantly different. Factors related to HIV infection in MSMs included syphilis infection, occupation, sexual orientation, venue for recruitment and hometown HIV prevalence. HIV rate and social-behavioral characteristics were found to vary with venues, with significantly higher rates in family clubs, parks and saunas, than entertainment venue. Molecular phylogenetical analysis showed that genetic clusters were related to receptive anal intercourse, short stay in Shenzhen, early age of first sex, and high hometown HIV prevalence. Venue-specific transmission chains were observed in 60% of the subjects. / Subjects and Methods A total of 2143 MSMs were recruited in Shenzhen from 2008 to 2009, including 1651 persons from time-location sampling (TLS) and 492 from respondent-driven sampling (RDS). A separate recruitment of MBs and other MSMs was applied in TLS surveys and a mixed sample of MSMs was applied in RDS. All subjects were interviewed and had blood tests for HIV and syphilis. HIV positive samples were further used for phylogenetic analysis. / Zhao, Jin / Adviser: Mingliang He. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 161-177). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.