1. School of Public Health, Capital Medical University, Beijing 100069, P. R. China
2. School of Public Health, Tianjin Medical University, Tianjin 300070, P. R. China
3. Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin Medical University, Tianjin 300070, P. R. China
4. Department of Social Medicine and Health Education, School of Public Health, Peking University, Beijing 100191, P. R. China
5. Beijing Municipal Key Laboratory of Clinical Epidemiology, Capital Medical University, Beijing 100069, P. R. China
6. Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430074, Hubei, P. R. China
7. Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430074, Hubei, P. R. China
8. School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, P. R. China