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<0.001), severity of drug dependence (AOR=1.05, p<0.01), economic pressure (AOR=1.07, p<0.05) and all studied psychosocial variables (e.g. depression, social support and gender power; AOR=0.70 to 1.67, p<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.

Conclusion. The significance of risk perception in predicting behavioral intention, hence actual future behaviors, is therefore evident. Conditional measures need to be used. HIV prevention can employ conditional risk perception approaches. Health behavioral theories can be strengthened by using such conditional measures on risk perceptions. The results add to this new and growing area of risk behavior research. / Introduction. Risk perception, a core element of key health behavioral theories and health interventions, is assumed to motivate people to avoid risk behaviors. Mixed findings however prevail in the literature due to methodological issues. Many of such studies are cross-sectional, using global risk perception measures that do not condition on type of risk behavior or partnership which may affect the level of risk. / Male injecting drug users (IDU) are driving the HIV epidemic in China and bridge HIV transmission to non-IDU female populations; they may be at risk of both unprotected sex and syringe sharing. HIV prevention targeting male IDU is greatly warranted and would benefit from understanding of the relationships between risk perceptions and behaviors, in the context of health behavioral theories such as the Health Action Process Approach (HAPA) model, which had not been applied to studies targeting IDU. / Objectives. This study refined the concepts and measures of HIV-related risk perception, conditioning on different types of behaviors and partners, and extended it to include others-directed risk perceptions. The relationship between such conditional risk perception measures and both prior risk behaviors and behavioral intention to avoid sex-related and drug-related risk behaviors in the future were investigated and were compared to those involving global unconditional risk perception measures. The nature of the aforementioned relationships, being motivational or reflective was investigated. A longitudinal component validated the predictive power of behavioral intention over actual future behaviors. / Results. Almost 90% of the respondents had had unprotected sex though <20% shared syringes with others in the last 6 months. Prior syringe sharing but not unprotected sex in the last 6 months was significantly associated with global unconditional risk perception measures. The picture is totally different when risk perception measures conditioned on type of sex partner and unprotected sex or syringe sharing were used instead of the global measures---higher levels of the conditional risk perception measures were significantly associated with higher levels of behavioral intention for consistent condom use and avoidance of syringe sharing, thus supporting the motivational hypothesis. Conditional others-directed risk perceptions (perceived risk of transmitting HIV to others via unprotected sex and syringe sharing) were also associated with the aforementioned behavioral intentions to avoid risk behaviors. A pilot longitudinal study showed that behavioral intentions strongly predict actual future behaviors. Other HAPA-based variables such as self-efficacy and outcome expectancies had predictive effects on behavioral intentions, independent from those of risk perceptions. / Subjects and methods. A total of 456 sexually active male IDU were recruited from Dazhou, Sichuan and Hengyang, Hunan, via snowball sampling. With informed consent, anonymous face-to-face interviews were conducted by trained and experienced staff of the local CDC in privacy settings. / Tsui, Hi Yi. / Adviser: Joseph Lau. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 118-130). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese; appendix in Chinese.