1. Department of Pediatrics, Hanyang University College of Medicine, Seoul, Korea.
2. Department of Pediatrics, Uijeongbu St. Mary's Hospital, The Catholic University of Korea College of Medicine, Uijeongbu, Korea.
3. Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea.
4. School of Medicine, Konkuk University, Seoul, Korea.
5. Department of Statistics, Pusan National University, Busan, Korea.