1. Boai Hospital of Zhongshan , Zhongshan City , Guangdong Province , China
2. Zhongshan Hospital of Sun-Yat-Sen University , Zhongshan City , Guangdong Province , China
3. Department of Clinical Epidemiology and Biostatistics, Children Health Advocacy Institute, Shanghai Children’s Medical Center , Shanghai Jiao Tong University School of Medicine , Shanghai , China
4. School of Public Health , Shanghai Jiao Tong University School of Medicine , Shanghai , China
5. Health Care Center for Primary and Secondary Schools , Zhongshan City , Guangdong Province , China