1. a Division of Health Improvement, School of Public Health and Primary Care , The Chinese University of Hong Kong , Beijing , China
2. b Centre for Medical Anthropology and Behavior Health, School of Sociology and Anthropology , Sun Yat Sen University , Shatin , Hong Kong
3. c Department of Psychology , The Chinese University of Hong Kong , Shatin , Hong Kong
4. d Department of HIV/AIDS Prevention , Shenzhen City CDC , Shenzhen , China
5. e Shenzhen Chronic Disease Hospital , Shenzhen , China
6. f Department of HIV/AIDS Prevention , Hunan Province CDC , Changsha , China
7. g Department of HIV/AIDS Prevention , Hengyang Center for Disease Control and Prevention (CDC) , Hengyang , China
8. h The 5th Hospital , Hengyang , China