[1] Sichuan University,West China School of Public Health and West China Fourth Hospital
[2] West China Second University Hospital of Sichuan University and Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University),undefined
[3] Ministry of Education,undefined
[4] Lu County Center for Disease Control and Prevention,undefined
[5] Sichuan Center for Disease Control and Prevention,undefined
[6] Pidu District Center for Disease Control and Prevention,undefined