1. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
3. Department of Pediatrics, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea.
4. Department of Pediatrics and Adolescent Medicine, Ajou University School of Medicine, Suwon, Korea.
5. Department of Pediatrics, Eulji University School of Medicine, Daejeon, Korea.