1. School of Public Health, Sun Yat-Sen University, Guangzhou, People’s Republic of China
2. JC School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, People’s Republic of China
3. Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, People’s Republic of China
4. Department of Community Health and Family Medicine, School of Public Health, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
5. Shenyang Consultation Centre of AIDS Aid and Health Service, Shenyang, People’s Republic of China