1. Department of Pediatrics, Inje University Ilsan Paik Hospital, Goyang, Korea.
2. Department of Pediatrics, College of Medicine, Chungnam National University, Daejeon, Korea.
3. Department of Pediatrics, Bundang Jesaeng Hospital, Seongnam, Korea.
4. Department of Pediatrics, College of Medicine, Yeungnam University, Daegu, Korea.
5. Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea.
6. Department of Pediatrics, Presbyterian Medical Center, Jeonju, Korea.
7. Department of Pediatrics, College of Medicine, Ewha Womans University, Seoul, Korea.
8. Department of Pediatrics, NHIC Ilsan Hospital, Seongnam, Korea.
9. Department of Pediatrics, Guro Hospital, Korea University College of Medicine, Korea.
10. Division of Chronic Disease Surveillance, Korea Centers for Disease Control and Prevention, Korea.
11. Health Promotion Team, Ministry of Health and Welfare, Seoul, Korea.