1. Department of Pediatrics, Severance Children's Hospital, Institute of Endocrinology, Yonsei University College of Medicine, Seoul, South Korea.
2. Department of Pediatrics, Kangwon National University Hospital, Kangwon National University College of Medicine, Kangwon, South Korea.
3. Department of Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, South Korea.
4. Department of Pediatrics, CHA Gangnam Medical Center, CHA University, Seoul, South Korea.