Affiliation: | 1. School of Public Health 2. Department of Medical Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan 450001, China 3. Department of Women's and Children's Public Health, Xi'an Municipal Maternal and Child Health Hospital, Xi'an, Shaanxi 710002, China 4. Data Center, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710006, China 5. School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases of Health Ministry, Xi'an Jiaotong University, Xi'an,Shaanxi 710061, China |