1. Department of Epidemiology and Health Statistics, Xiangya School of Public Health, Central South University, Changsha, Hunan, China
2. Department of Information Management, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
3. Department of Changsha Medical University Public Health Institute, Changsha, Hunan, China
4. NHC Key Laboratory of Birth Defect for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China
5. Hunan Provincial Key Laboratory of Clinical Epidemiology, Changsha, Hunan, China