1. Division of Public Health, Center for Community Medicine, Jichi Medical University
2. Health Service Center, Jichi Medical University
3. Department of Neonatology, Toho University School of Medicine
4. Department of Pediatrics, Jichi Medical University
5. Department of Pediatrics, Graduate School of Medicine, Gifu University
6. Department of Pediatrics, Showa University of Medicine
7. Department of Pediatrics, Tokyo University