Sichuan University - Department of Maternal, Child and Adolescent Health, Sichuan Center for Disease Control and Prevention, Shandong University, Huazhong University of Science and Technology - School of Medicine and Health Management, Guangzhou Medical University, Chinese Center for Disease Control and Prevention (China CDC), Sichuan University, Sichuan University and Sichuan University - Department of Epidemiology and Biostatistics