1. Department of Health Sciences, Graduate School, Korea University, Seoul, Korea.
2. Department of Public Health Policy, Gyeonggi Public Health Policy Institute, Seongnam, Korea.
3. Department of Pediatrics, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea.
4. Department of Pediatrics, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.
5. Department of Pediatrics, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.