1. Department of Epidemiology and Biostatistics, School of Public Health, Medical College of Soochow University, Suzhou, China
2. Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA
3. Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA
4. Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA