1. Department of Maternal and Child Health, School of Public Health, Peking University, Beijing, China
2. Environmental and Spatial Epidemiology Research Center, National Human Genetic Resources Center, Beijing, China
3. UNICEF China, Beijing, China
4. Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States of America
5. Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
6. Beijing Camford Royal School, Beijing, China