1. Department of Pediatrics; University of Tokyo Hospital; Tokyo Japan
2. Department of Pediatrics; Kikkoman General Hospital; Chiba Japan
3. PAL Children's Clinic; Gunma Japan
4. Department of Health Economics and Epidemiology Research; School of Public Health; University of Tokyo; Tokyo Japan
5. Department of Clinical Data Management and Research; Clinical Research Center; National Hospital Organization Headquarters; Tokyo Japan
6. Health Policy and Informatics Section; Department of Health Policy; Tokyo Medical and Dental University Graduate School; Tokyo Japan