1. Department of Epidemiology and Biostatistics, West China School of Public Health, Sichuan University, Chengdu, People's Republic of China.
2. Department of Discipline Construction, West China Hospital, Sichuan University, Chengdu, People's Republic of China.
3. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina.
4. Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.
5. London School of Hygiene and Tropical Medicine, London, United Kingdom.
6. The Comprehensive Guidance Center of Women's Health, Women's and Children's Hospital of Sichuan Province, Chengdu, People's Republic of China.
7. School of Public Health, Sun Yat-Sen University, Guangzhou, People's Republic of China.