published_or_final_version / Public Health / Master / Master of Public Health

一個大型的多中心臨床試驗 (HPTN052) 於2011年發表研究結論，假如治療中的愛滋病患者能保持病毒載量低水平，他們傳播愛滋病予性伴侶的機會是十分輕微的。這些結論促使利用病毒載量數據去形容愛滋病流行概况及評估高效抗逆轉錄病毒療法 (HAART) 干預策略對流行概况的影響。本研究旨在應用社區病毒載量去模擬香港愛滋病流行概况。 / 本研究收集了香港兩間主要愛滋病專科裡愛滋病患者縱向臨床數據，這些匿名的數據根據美國疾病預防控制中心所提議的人群病毒載量框架整合成流行病數據。其中社區、護理群及監測群病毒載量的計算是為了描述愛滋病流行概況，而新創的全社區病毒載量是用於估計社區裡確診與尚未確診的愛滋病感染者的集體病毒載量。香港未來愛滋病流行概況則利用決定性倉室模型模擬。異性模型透過性別分成兩個 (男女) 有聯繫的小模型，同性模型則用系統進化分析的近鄰結合法去劃分成16個獨立的小模型。除了基於現有情況模擬概況，治療、測試和混合干預策略以及外來感染的影響也被模擬。 / 從4362個病患中，一共收集了76,350CD4、64,412病毒載量和1042基因序列的回顧數據 (1985-2012)。當中有83%病患是男性、72%是中國人、89%是透過性接觸感染、74%曾經接受治療。能達到低病毒載量的病患百分比由1997年11%升至2012年76%，與HAART的推行情況方向一致。全社區病毒載量所顯示的上升趨勢於異性群和同性群中較其他病毒載量指標早五年出現。於2010-2020，異性群的愛滋病流行概況將維持不變，而同性群的流行概況將穩步上升但不是指數上升。干預策略中，以混合干預加上高治療保留率的策略對同性和異性群最有效，但增加重點測試對異性群比較可行，因為它舒緩了診斷延誤。另外，外來感染會影響干預策略的成效。 / 假如沒有包含病毒載量因素、外來感染和劃分模型，推測結果會高估流行概況，而治療覆蓋率的影響也不能被反映。基於人群病毒載量的重要性，定期收集所有專科的病毒載量數據並加以整合應該成為監測的一部份。這對於有廣泛治療覆蓋率的香港去研究流行概況是十分重要。 / Introduction: In 2011, a large multicentre trial (HPTN052) concluded that HIV+ persons on treatment with suppressed viral load (SVL) have minimal risk of virus transmission to their seronegative partners through sexual intercourse. These results provided evidence for the epidemiological use of viral load data to describe the HIV epidemics and assess impacts of treatment interventions. This study aims at modelling the HIV epidemic in Hong Kong by incorporating population-level viral load measures. / Methods: Longitudinal clinical data of patients attending two major HIV specialist services in Hong Kong were collected. The anonymized data were combined, adjusted and incorporated in an epidemiologic dataset in accordance with the CDC framework of viral load measures at population level. Specifically, community, in-care and monitored viral load were calculated to describe the HIV epidemic. Full community viral load, a new measure, was developed to infer the viral load burden of both diagnosed and undiagnosed individuals in the community. The HIV epidemic was then projected in a deterministic compartmental model. Gender was used to divide heterosexual model into two interrelated sub-models, while phylogenetic analysis (neighbour-joining tree) was applied to divide men-who-have-sex-with-men (MSM) model into 16 independent sub-models. Intervention scenarios of treatment coverage, testing coverage and retention expansion, and influence of non-local infection were projected and compared by modelling. / Results: A total of 76,350 CD4 and 64,412 viral load measurements of 4362 patients, and 1042 sequences were collected retrospectively (1985-2012). Among the patients included, 89% had acquired infection through sexual intercourse, and 74% had been started on highly active antiretroviral therapy (HAART). From viral load perspective, the proportion of patients in care with SVL (≤500copies/mL) increased sharply from 11% in 1997 to 76% in 2012, coinciding with the implementation of HAART. The growth curve of full community viral load was 5 years ahead of other viral load measures of heterosexuals and MSM. In 2010-2020, the HIV epidemic in heterosexuals would neither grow nor die down while the epidemic in MSM would continue to grow steadily but not exponentially. Among scenarios examined, test-and-treat intervention with high retention rate would be the most effective strategy for controlling the MSM and heterosexual epidemic. However, increasing the HIV testing rate for high risk people would be more feasible and impactful for the heterosexual, as a result of the early detection of HIV which would otherwise become late diagnoses. Non-local infection would affect the impact of interventions on epidemic control. / Conclusion: Without the inclusion of viral load measures, non-local infection and model delineation by subpopulations, epidemiologic projection results could be overestimated. Also, the impacts of treatment coverage on epidemic cannot be reflected if viral load measure is not included for describing epidemic growth. Acknowledging the importance of viral load measure, regular collection and aggregation of viral load measurements from all HIV clinics is recommended to form part of the HIV surveillance system. Such provision is important for studying HIV epidemiology descriptively and analytically in Hong Kong where coverage of HIV care is relatively extensive. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wong, Ngai Sze. / Thesis (Ph.D.) Chinese University of Hong Kong, 2015. / Includes bibliographical references (leaves 204-219). / Abstracts also in Chinese.

Background: The epidemic of HIV among MSM in China shows a hiking trend since 2003. The current intervention strategies in China lack effectiveness to curb the trend. It is imperative to review the interventions for HIV prevention among MSM in other countries to provide evidence for the future intervention design in China. Objectives: This study aimed to review the HIV prevention interventions among men who have sex with men(MSM) in order to identify appropriate intervention strategies and practices to be employed in China. Methods: Studies were searched in Pubmed database. Studies of interventions targeting MSM for HIV prevention among MSM in other countries were included in this systematic review. The search results were also filtered by the study type (i.e. RCT).The results and design of the studies were analyzed and discussed. Results: The studies in this review were analysed in terms of the study design, sampling method, retention and intervention strategies. High risk sexual activity, condom use, HIV testing and HIV knowledge were used as outcome measurements. The findings indicated that the interventions were in general effective in reducing the sexual risk behavior and increasing the intention to have a HIV test. The design of RCT offers stronger evidence of the intervention effects. The intervention strategies combined with internet were more personalized and confidential. Conclusions: Future intervention design in China could consider the strengths of interventions undertaken in other countries in order to improve the effectiveness and sustainability. In consideration of the context of China, this review made some suggestions for more effective implementation of interventions for HIV prevention among MSM in China. / published_or_final_version / Public Health / Master / Master of Public Health

Background: Men who have sex with men (MSM) are a high risk group of human immunodeficiency virus (HIV) infection. Since 2003, HIV prevalence and incidence among MSM in China has increased alarmingly. And then numerous control measures targeting risk reduction of HIV infection among MSM have been implemented. However, previous studies varied in methodologies, prevention or interventions, and most studies only investigated one or several of control measures. Moreover, there are no existing systematic reviews on the effectiveness of integrated control measures against HIV infection. Therefore, this systematic review was conducted to assess the effectiveness of control measures against HIV infection among MSM in China, in terms of condom use, sexual behaviours, awareness of HIV knowledge, HIV counseling and testing, and HIV prevalence and incidence. Methods: A total of 154 articles were first retrieved from English database PubMed, and 114 articles from Chinese database CNKI. 19 English and Chinese articles that met the inclusion criteria were included in this systematically review. Results: The common control measures, including distribution and use of condoms and lubricant, high risk behavioural interventions, education of HIV knowledge, peer interventions, HIV testing and counseling, and MSM community or venue based interventions, are effective in increasing condom use in the anal sex, reducing risk sexual behaviours, improving awareness of HIV knowledge, and promoting the participation of HIV counseling and testing, which are all beneficial to prevent HIV infection among MSM. These findings may be influenced by the design of questions and the standard, and the response of MSM to questions. As for HIV prevalence and incidence, the effectiveness on them is uncertain, probably owing to inappropriate timing of conducting control measures, the short follow-up period, the small sample size or the scale of study. Future studies need to improve sampling method, and extend follow-up time and the study scale appropriately. Conclusion: Based on this systematic review, the control measures are effective in increasing condom use, reducing risk sexual behaviours, improving awareness of HIV knowledge and promoting the participation of HIV counseling and testing, while the effectiveness on HIV prevalence and incidence is uncertain among MSM in China. In future, more policy researches on HIV/AIDS burden, MSM and control measures are needed to provide an evidence base for policy change. In practice, policy makers and researchers need to promote structural control measures targeting different typologies of MSM. And the more effective way in conducting control measures needs the multi-sector cooperation, especially the cooperation between the governmental organizations and MSM community. / published_or_final_version / Public Health / Master / Master of Public Health

Background In the recent decade resurgence of syphilis was noted in a global scale, especially in high-risk communities like men who have sex with men (MSM) and commercial sex workers (CSW). Syphilis co-infection is important in people living with human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) because of their similar transmission routes, mutual interactions at pathophysiology level, relation to socioeconomic factors and public health implications. Methods Retrospective analysis of syphilis co-infections among the HIV/AIDS patients who have been under the care of the AIDS Clinical Service, Queen Elizabeth Hospital of Hong Kong which has served as a tertiary referral center since the beginning of the AIDS epidemic. Details of syphilis co-infection including their clinical stages on diagnosis, evidence of central nervous system (CNS) invasion and recurrence were analyzed. Results In the 1,567 subjects studied 223 (14.2%) had HIV/syphilis co-infection. There are significantly more MSM in the HIV/syphilis co-infected group (P < 0.001). Among the coinfected, 111 (49.8%) had undiagnosed and untreated syphilis at the time of HIV/AIDS diagnosis. Sixty two subjects (27.8%) acquired syphilis as totally new infections after followed up for HIV/AIDS, with a median time of 284.6 weeks (range 3.7-862.3 weeks). Twenty subjects (9.0%) showed evidence of neurosyphilis on cerebrospinal fluid study. Thirty two (14.3%) had recurrent syphilis infections and more than 80% of them occurred in MSM. The total follow up duration was 8616.58 person-years. By Poisson regression, the adjusted total syphilis incidence was 7.07 cases per 100 person-years. MSM had the highest syphilis incidence of 20.25 cases per 100 person-years. In addition syphilis incidence in MSM recruited after the year 2000 was higher than those MSM recruited before. When Comparing subjects with HIV infection diagnosed before 2000 with those having HIV infection diagnosed after 2000, latter have higher cumulative incidence of first syphilis events (P < 0.001). Using Cox regression analysis, MSM (hazard ratio 3.26, 95% CI 1.93 – 5.51, P < 0.0005), bisexual contact (hazard ratio 2.95, 95% CI 1.49 – 5.82, P < 0.005) and infection with HIV-1 subtype B (hazard ratio 1.65, 95% CI 1.08 – 2.53, P = 0.02) were associated with development of first event of syphilis infection during follow up. Conclusions The result of this study corresponded to the global trend of HIV/syphilis syndemic. New and recurrent syphilis infections continued to appear after combination antiretroviral therapy (cART) initiation. MSM, bisexual subjects and infection by HIV-1 subtype B were risk factors for syphilis events. MSM contained the highest syphilis burden. Urgent attention and measures are needed to target syphilis and HIV infection in the Hong Kong MSM population. / published_or_final_version / Public Health / Master / Master of Public Health

Background AIDS as a burden to all over the world caused serious problems in some developing regions by threatening health of the population and stability of the society, especially in cross-border areas that have a complex crowd with many migrants. The HIV/AIDS situation of cross-border FSWs in China-Burma border region is not comprehensively known so far. Only have a clearly understanding of their circumstances, can health workers provide target health services for them. Objectives In view of the increasing HIV epidemic in China-Burma border areas in the past several years, this study tries to understand the HIV prevalence among two groups of cross-border FSWs; further describe socio-demographic characteristics in each group; identify risk behaviours related to consistent condom use; interpret HIV risk factors that contribute to HIV infection in each group of FSWs; describe health services currently being provided and particular health services needs of these FSWs. Methods This cross-sectional research design comprises two parts. Part one is a questionnaire based face-to-face interview to obtain self-reported information. A total of 142 cross-border FSWs were recruited from Ruili City, China (Burmese FSWs) and Laukkai City, Burma (Chinese FSWs). Convenience sampling method was used. Risk factors that mutually adjusted were analysed in two logistic regression models regarding condom use and HIV infection in each group and odds ratios (ORs) were obtained with 95% confidence intervals (CI). Part two of this study is voluntary venous blood drawing and testing for HIV infection. 136 cross-border FSWs [6 of part one (questionnaire interview) participants refused] attended part two study. Results In general, Burmese cross-border FSWs tended to be older, lower educated and married and had higher HIV prevalence (18.8%) compared with Chinese women (5%). Frequency of condom use with the paying clients was higher than with the regular partners in both groups. After adjustment, drug users had statistically significant OR of 6.89 (95% CI: 1.12 to 42.38) for condom use frequency in last sex behaviour compare to non-users in Burmese FSWs; based on Chinese FSWs’ condom use model, the more paying clients, the higher frequency of condom use they had (OR: 0.63 with 95% CI: 0.45 to 0.9). Age (year of birth) had a significant impact with two opposite direction on HIV infection in both Burmese group and the whole study population: positively relate to HIV infection in Burmese model (OR: 1.20 with 95% CI: 1.02 to 1.41); nevertheless, when Chinese ones were added, year of birth negatively related to HIV infection with OR of 0.84 (95% CI: 0.74 to 0.96). Generally, Burmese women had proportionally higher health services acceptance proportion to Chinese women. “HIV/AIDS awareness” and “HIV counselling and testing” were the most widely provided services in Burmese and Chinese group, respectively, and “free condom distribution” was the most needed health services of both cross-border FSWs. Conclusion This study provides better understanding about cross-border FSWs working in China-Burma border areas in which little information about their demographics, HIV infection, and high-risk behaviour has been known. From public health perspective, development and implementation of public health interventions and policies can get inspiration and support from this study. / published_or_final_version / Public Health / Master / Master of Public Health

Tam, Ka Po. / Thesis submitted in: September 2008. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 151-161). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Human Immunodeficiency Virus --- p.1 / Chapter 1.2 --- Sexual Transmission of HIV --- p.3 / Chapter 1.3 --- HIV Prevalence in MSM Worldwide --- p.5 / Chapter 1.4 --- Risk Factors for Homosexual Men --- p.8 / Chapter 1.4.1 --- Individual Factors --- p.8 / Chapter 1.4.2 --- Societal Factors --- p.12 / Chapter 1.5 --- HIV Prevalence of MSM in Hong Kong --- p.17 / Chapter 2 --- Literature Review --- p.21 / Chapter 2.1 --- The Literature Search --- p.22 / Chapter 2.2 --- Results --- p.25 / Chapter 2.3 --- Reasons to Conduct Social Network Study --- p.26 / Chapter 2.4 --- Review on Methodologies --- p.29 / Chapter 2.4.1 --- Data Source --- p.29 / Chapter 2.4.2 --- Sampling Methods --- p.30 / Chapter 2.5 --- Review on Major Findings --- p.33 / Chapter 2.5.1 --- Individual Characteristics --- p.33 / Chapter 2.5.2 --- Partnerśة Characteristics --- p.34 / Chapter 2.5.3 --- Network Characteristics --- p.38 / Chapter 2.6 --- Critique --- p.40 / Chapter 2.7 --- Implication --- p.46 / Chapter 3 --- Methods --- p.49 / Chapter 3.1 --- Study Design --- p.49 / Chapter 3.1.1 --- Sampling --- p.50 / Chapter 3.1.2 --- Terminology --- p.51 / Chapter 3.2 --- Instruments --- p.56 / Chapter 3.2.1 --- Self-administered Questionnaire --- p.56 / Chapter 3.2.2 --- Demographics --- p.57 / Chapter 3.2.3 --- Setting of Infection --- p.57 / Chapter 3.2.4 --- Partnership Pattern --- p.59 / Chapter 3.2.5 --- Semi-structured Interviewing Guide --- p.61 / Chapter 3.2.6 --- Last Sexual Episode --- p.62 / Chapter 3.2.7 --- Sexual Role --- p.63 / Chapter 3.2.8 --- Partner Selection --- p.63 / Chapter 3.2.9 --- Bem Sex-Role Inventory --- p.64 / Chapter 3.3 --- Data Analysis --- p.66 / Chapter 3.4 --- Ethical Considerations --- p.70 / Chapter 4 --- Results --- p.74 / Chapter 4.1 --- Sampling --- p.74 / Chapter 4.2 --- Characteristics of Respondents --- p.75 / Chapter 4.2.1 --- Demographics --- p.75 / Chapter 4.2.2 --- Settings of Infection --- p.77 / Chapter 4.2.3 --- HIV Test --- p.79 / Chapter 4.3 --- Partnership Pattern --- p.82 / Chapter 4.3.1 --- Partner Types --- p.83 / Chapter 4.3.2 --- Location for Partner Sourcing --- p.84 / Chapter 4.3.3 --- Characteristics of Sex Partners --- p.86 / Chapter 4.3.4 --- Sexual Behavioural Pattern --- p.87 / Chapter 4.3.5 --- The Influence of Partner Types --- p.92 / Chapter 4.3.6 --- Last Sex with Lover(s) and/or Regular Partner(s) --- p.95 / Chapter 4.3.7 --- Sexual Role in Anal Intercourse --- p.98 / Chapter 4.4 --- Networking Pattern --- p.103 / Chapter 4.4.1 --- Individual Network --- p.104 / Chapter 4.4.2 --- Cluster Analysis (with 2-mode correspondence analysis) --- p.108 / Chapter 4.4.3 --- Social Network Analysis --- p.115 / Chapter 5 --- Discussion --- p.122 / Chapter 5.1 --- Possible Existence of 2 Sexual Networks in Hong Kong --- p.123 / Chapter 5.1.1 --- Network Configuration --- p.123 / Chapter 5.1.2 --- Network-related Behaviours --- p.128 / Chapter 5.2 --- Impact of Partnership Pattern on HIV Transmission --- p.129 / Chapter 5.3 --- The Importance of Sexual Role --- p.135 / Chapter 5.4 --- Limitations --- p.136 / Chapter 5.5 --- Implications --- p.141 / Appendices --- p.145 / Chapter A --- Self-administered Questionnaire --- p.145 / Bibliography --- p.151

BACKGROUND The coverage of HIV/AIDS behavioral surveillance among MSM in China falls far short of what is necessary as the current approach is expensive and time consuming. In addition MSM are difficult to reach in China. Internet-based behavioral surveys have demonstrated a number of advantages compared with the traditional paper-pen method. Chinese MSM are avid users of the Internet. Use of the internet provides an opportunity to access this hard-to-reach population and explore their use of the Internet for sexual purposes as well as to assess risk behaviors among MSM internet users. This thesis aimed to explore the trends in risk behaviors and HIV prevalence among MSM using traditional community-based surveys and Internet surveys, and to analyze the potential of web-based behavioral surveillance among MSM by comparing the differences between Internet and community-based MSM samples, and then to provide insights for the future HIV/AIDS behavioral surveillance, epidemic estimation and prediction as well as health intervention among the Chinese MSM population. METHODS This study has three components. The first focuses on trends in HIV risk behaviors and prevalence among MSM in Harbin in northeast China, based on community-based surveys. Eligible participants were approached by peer recruiters in traditional gay venues and then interviewed by health professionals with a standard questionnaire. Urine samples were collected to screen their HIV status. The second part presents two cross-sectional, Internet-based surveys among MSM in China in 2006 and 2007. The study website was advertised on three selected gay websites using a series of banners, pop-ups and text notifications. After providing consent to the survey, eligible participants were invited to complete an online questionnaire. The third component compares the demographic characteristics and risk behaviors of two samples of Chinese MSM. Participants living in Heilongjiang Province were extracted from the 2006 online survey dataset to compare with the community sample of MSM recruited in Harbin, the capital city of Heilongjiang Province in the same year. KEY FINDINGS Community-based behavioral surveillance Among MSM in Harbin, a trend was observed towards more self-identifying as homosexual (from 58% to 80%) and more living with a male partner (from 12% to 41%) over the study period 2002-06. Although there was a trend towards a reduction in the rate of never using a condom and an increase in the rate of always using condoms during anal sex in the past six months, the prevalence of unprotected anal intercourse (UAI) still remained at high level (from 90% in 2002 to 72% in 2006). Most respondents reported having multiple male sexual partners (≥ 2) in the past six months: 86.5% in 2002, 76.0% in 2004 and 91.6% in 2006. The HIV prevalence (2.2%, 15/674) among MSM in Harbin in 2006 was higher than that in previous survey years (1.3% in 2002 and 0.94% in 2004), but no statistically significant change was detected. Internet-based behavioral surveys Gay website users in China are young and well educated. The majority (85%) have used the Internet to seek sex and meeting sexual partners online, which is one of the most common reasons for visiting gay websites. Traditional gay venues still play an important role in the sex seeking process, especially for MSM who are older and less educated. Gay website users are vulnerable to HIV/AIDS given their high prevalence of UAI (56.6%) and multiple male sexual partners (66.5%). The type of partners plays an important role in determining consistent condom use. An increase in condom use was observed among MSM having sex between commercial partners relative to those having sex with non-regular partners and regular partners. Among the Internet sample, participants who have regular partners are less likely to have sex with females, less likely to have multiple partners and less likely to engage in commercial sex behaviors than those who do not. Comparisons between Internet and community samples There are significant differences in terms of demographic characteristics and risk behaviors between the Internet and community samples of MSM. The Internet sample was significantly younger, more educated and more likely to be students and self identify as homosexual. Among those who had anal sex in the past six months, the Internet sample tended to use condoms less consistently than the community sample. However, using the total sample size as the denominator to calculate the prevalence of UAI, no significant difference between the two samples was observed (AOR 1.02, CI 0.73-1.43, p = 0.905). After adjusting for differences in demographic characteristics, the community sample was more likely to have had sex with females (AOR 2.01, CI 1.22-3.30, p = 0.006) and have had ≥ 6 male partners in the previous six months than the Internet sample (46.1% vs. 20.2%; AOR 4.88, CI 3.51-6.80, p < 0.001). The mean number of male partners for the community sample was 13.5 ± 16.8, whereas it was 6.0 ± 12.2 for the Internet sample. CONCLUSIONS Although there is a trend towards an increase in condom use among MSM in China, they are vulnerable to HIV/AIDS infection given their high prevalence of UAI and multiple sexual partners. Public sector officials at all levels need to recognize this risk for HIV transmission. Health promotion and behavioral interventions should be enforced and scaled up to meet the need for controlling HIV transmission among MSM in China. Since the Internet has become a risk environment for MSM and the online MSM population is significantly different from the traditional community MSM group, online MSM should be included as a risk group in national HIV sentinel and behavioral surveillance and the coverage of surveillance for this specific group should be expanded to better understand the health promotion needs of this community as part of an HIV/AIDS strategy in China. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1339648 / Thesis (Ph.D.) - University of Adelaide, School of Population Health and Clinical Practice, 2008

Conclusions. The "bridging effect" for HIV transmission is evident. Variables predicting condom use during commercial sex are multidimensional. Integrative programs are hence required. Methadone clinics may offer a platform for offering such services to IDU-FSWs. The performance of the TPB could be enhanced by addition of external variables; its applicability varies according to the wellbeing status of the IDU-FSWs. Future randomized control studies are warranted to design effective evidence-based programs targeting IDU-FSWs. / Introduction. Injecting drug users (IDUs) drive the HIV epidemic in China. Female injecting drug users who are sex workers (IDU-FSWs) is a strategic "bridge population" for HIV transmission from the IDU to non-IDU populations. Background characteristics, health behavioral theories (e.g. the Theory of Planned Behavior, TPB), drug dependence, economic pressure, psychological problems, social support and gender power are potential predictors of condom use during commercial sex among IDU-FSWs. Most of these associations have not been investigated in China or elsewhere, and the TPB has not been applied to HIV-vulnerable populations in China. A knowledge gap exists. / Objectives. This study validated two instruments measuring severity of drug dependence. The prevalence of inconsistent condom use among IDU-FSWs and its associations with the aforementioned variables were investigated. The hypotheses that different blocks of variables would have independent effects on condom use during commercial sex, and the effects of TPB-related variables on condom use would be moderated by some external variables (e.g. severity of drug dependence) were tested. / Results. The Opiate Addiction Severity Inventory-Revised (OASI-R) was fully validated in the Study I. Around 6.8% of IDU-FSWs were HIV positive and respectively 48% and 64% of them practiced needle sharing and unprotected commercial sex (last six months). After adjusting for significant background variables, the five TPB-related variables (AOR=0.43 to 1.92, p&lt;0.001), severity of drug dependence (AOR=1.05, p&lt;0.01), economic pressure (AOR=1.07, p&lt;0.05) and all studied psychosocial variables (e.g. depression, social support and gender power; AOR=0.70 to 1.67, p&lt;0.05) were significantly associated with condom use during commercial sex. / Subjects and methods. Two cross-sectional studies were conducted. In Study I, 178 non-institutionalized drug users were interviewed in Dazhou, Sichuan. In Study II, 281 non-institutionalized IDU-FSWs were interviewed in Dazhou, Sichuan and Hengyang, Hunan, using snowballing method and face-to-face interviews. Statistical methods such as hierarchical and interaction modeling, stratification analysis, ROC method were used in this study. / The final hierarchical model predicting condom use during commercial sex included variables coming from four blocks of independent variables, with ROC area = 94% and sensitivity/specificity = 0.84/0.91. A "Wellbeing Status Index" moderated the associations between some of the TPB-related variables and condom use during commercial sex. / Gu, Jing. / Adviser: Joseph T. F. Lau. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3462. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 228-246). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Introduction. The HIV prevalence among men who have sex with men (MSM) in China keeps increasing sharply. A high proportion of the MSM in China have male regular sex partner (RP) and prevalence of unprotected anal intercourse (UAI) involving such RP is higher than when non-RP is involved. Trust, intimacy and cognitive factors are the factors associated with UAI with RP. Several cross-sectional studies have been demonstrated the important factors associated with UAI with RP among MSM in China. However, no study about intervention for MSM-RP is found to be conducted. To reduce UAI with RP, an intervention tailored to RP is urgently developed and identified its efficacy. / Objectives. The study aimed to describe the prevalence of UAI, as well as of which associated factors among MSM-RP in Beijing and Chengdu, China, and to evaluate the efficacy of an enhanced HIV voluntary counseling and testing (VCT) in increasing condom use with RP among MSMRP in China by a randomized controlled trial (RCT). / Subjects and Methods. A cross-sectional survey and a randomized controlled trial have been conducted. For the cross-sectional survey, total 307 HIV negative MSM who have RP have been recruited by three ways. Face to face interview has been conducted to participants. Based on the associated factors found in the cross-sectional survey, interventions including video, education leaflets and enhanced counseling contents have been tailored to RP among MSMRP. For the randomized controlled trial, total 336 MSMRP have been recruited and randomly assigned 169 subjects to the Intervention Group in which participants have been given enhanced VCT plus an audio-visual and four leaflets components and 167 subjects to the Control Group in which participants have been given only standard-of-care VCT at the baseline. Evaluation was conducted at Month 3 and 6. Statistical methods such as descriptive analyses, Chi-square test and logistic regression were used in this study. / Results. The results have been found were the prevalence of UAI with RP among MSMRP was 52.4%, and the Theory of Planned Behavior (TPB) related cognitions, trust, intimacy, depression and anxiety were associated with UAI with RP among MSMRP. In the RCT study, participants in the Intervention Group had less UAI (36.1% vs. 49.1%) than those of the Control Group at Month 3. / Conclusions. This study showed a high prevalence of UAI among MSMRP, whilst trust, intimacy and cognitive factors were associated with UAI with RP. The efficacy of Enhanced VCT tailored to RP has been identified. The acceptability and feasibility of the tailored intervention were demonstrated. In the future HIV prevention programs, the effective intervention should be considered to be incorporated into standard-of-care VCT procedures and be implemented in the specific population. / 介紹：中國男男性接觸者中的愛滋病發病率一直保持著上升的狀態。而在中國男男性接觸者中有很大比例存在著固定性伴侶。男男性接觸者同固定性伴發生無保護肛交行為的比例大於其同非固定性伴。信任，親密以及認知因素已經被證實是影響男男性接觸者同其固定性伴發生無保護肛交行為的因素。但是在中國還沒有發現專門針對有固定性伴的男男性接觸者的干預研究。為了降低男男性接觸者同其固定性伴的無保護肛交的發生率，針對有固定性伴的男男性接觸者的干預方法應該被發展同時證實其有效性。 / 目的：本研究目的在於調查北京及成都男男性接觸者的固定性伴的比例，及其影響因素，包括健康行為理論的影響因素以及人際關係因素。同時，本研究也驗證了以隨機對照實驗來評估針對有固定性伴男男性接觸者的提高型愛滋病自願檢測諮詢對減少其高危性行為的效果。 / 對象與方法：本研究由橫斷面研究以及隨機對照試驗組成。在橫斷面調查中，307名愛滋病陰性的有固定性伴的男男性接觸者被招募。基於在橫斷面調查中發現的對男男性接觸者與固定性伴間發生無保護性行為的影響因素，一項專門針對有固定性伴的男男性接觸者的提高型愛滋病自願檢測諮詢干預方法被發展應用了隨機對照試驗中已驗證其有效性。在隨機對照試驗中，169名和167名研究對象被招募並分別被隨機分配到干預組（接受提高型愛滋病自願檢測諮詢）和對照組（接受標準型愛滋病自願檢測諮詢）中。分別於干預後的3個月和6個月回訪進行干預結果的評估。在本次研究中，運用了卡方检验和logistic回歸等統計學方法。 / 結果：在橫斷面調查中發現，男男性接觸者同固定性伴的無保護肛交發生率為52.4%。影響與固定性伴無保護肛交的因素包括：健康行為理論（TPB）相關的認知，信任，親密以及抑鬱和焦慮。在隨機對照試驗中發現，在3個月隨訪中干預組的男男性接觸者與固定性伴發生無保護肛交的比例較對照組明顯降低（36.1% vs. 49.1%）。 / 結論：本研究結果顯示中國男男性接觸者的固定性伴的比例很高，同時幾乎一半的有固定性伴的的男男性接觸者同時有多個性伴，這就有增加感染愛滋病及其他性病的風險。一項針對有固定性伴的男男性接觸者設計的提高型愛滋病自願檢測諮詢方法在降低其危險性行為上的可接受性和有效性已經被證實。提示在今後的愛滋病干預項目中可以進一步的推廣應用。 / Li, Chunrong. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 149-178). / Abstracts and appendixes also in Chinese. / Title from PDF title page (viewed on 05, October, 2016). / Li, Chunrong. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.