1 Department of Epidemiology/Department of Maternal, Child and Adolescent Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China.
2 Department of Growth and Development, Capital Institute of Pediatrics, Beijing, China.
3 Department of Nutrition and Food Hygiene, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China.