1. Key Laboratory of Environmental Medicine and Engineering, Ministry of Education, Department of Epidemiology and Medical Statistics, School of Public Health, Southeast University, Nanjing City, China
2. Department of Health Policy and Management, Nanjing Medical University, Nanjing City, China
3. Hekou Center for Disease Control and Prevention, Hekou, China
4. National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing City, China