1. Department of Epidemiology and Health Statistics, School of Public Health, Capital Medical University, Beijing 100069, China
2. Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing, China
3. Department of Epidemiology, School of Public Health, Shandong University, Jinan, China
4. Department of Food Hygiene and Nutrition, School of Public Health, Shandong University, Jinan, China