1. Department of Epidemiology; Fielding School of Public Health, University of California; Los Angeles CA
2. Department of Epidemiology; School of Public Health, Fudan University; Shanghai China
3. Jiangsu Provincial Center for Disease Control and Prevention; Nanjing Jiangsu China
4. Dafeng Center for Disease Control and Prevention; Dafeng Jiangsu China
5. Ganyu Center for Disease Control and Prevention; Ganyu Jiangsu China
6. Chuzhou County Center for Disease Control and Prevention; Chuzhou Jiangsu China
7. Tongshan County Center for Disease control and Prevention; Tongshan Jiangsu China
8. Department of Social and Preventive Medicine, School of Public Health and Health Professions; University at Buffalo, The State University of New York; Buffalo NY
9. Department of Epidemiology; School of Public Health, Peking University; Beijing China