1. Department of Pediatrics, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.
2. Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
3. Department of Pediatrics, Inje University Seoul Paik Hospital, Seoul, Korea.
4. Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
5. Department of Pediatrics, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea.
6. Department of Pediatrics, Soonchunhyang University School of Medicine, Bucheon, Korea.
7. Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea.
8. Department of Pediatrics, School of Medicine, The Catholic University of Korea, Uijeongbu St. Mary's Hospital, Uijeongbu, Korea.
9. Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea.
10. Department of Pediatrics, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
11. Department of Pediatrics, School of Medicine, Inha University, Incheon, Korea.
12. Department of Pediatrics, Pediatric Allergy and Respiratory Center, Soonchunhyang University College of Medicine, Seoul, Korea.
13. Department of Pediatrics, School of Medicine, The Catholic University of Korea, Bucheon St. Mary's Hospital, Bucheon, Korea.
14. Department of Pediatrics, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Korea.
15. Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
16. Department of Pediatrics, Pusan National University Yangsan Hospital, Yangsan, Korea.
17. Department of Pediatrics, Gangnam CHA Medical Center CHA University School of Medicine, Seoul, Korea.
18. Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.
19. Department of Pediatrics, Mediplex Sejong Hospital, Incheon, Korea.
20. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
21. Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Korea.
22. Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.