1. Department of Medical Statistics and Epidemiology, Guangzhou Key Laboratory of Environmental Pollution and Health Assessment, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-Sen University, Guangzhou, China;
2. Shenzhen Center for Disease Control and Prevention, Shenzhen, China;
3. Department of Pediatrics, Division of Behavioral Medicine, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA;
4. Department of Social and Preventive Medicine, School of Public Health and Health Professions, State University of New York at Buffalo, Buffalo, NY, USA;
5. Shenzhen Women and Children’s Hospital, Shenzhen, China;
6. Foshan Women and Children’s Hospital, Foshan, China;
7. Department of Information Management, Xinhua College, Sun Yat-Sen University, Guangzhou, China