1. Department of Pediatrics, Childhood Asthma and Atopy Center, Humidifier Disinfectant Health Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Department of Information Management, Medical Record Information Team, Hanyang University Medical Center, Seoul, Korea.
3. Humidifier Disinfectant Health Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Pediatrics, Soonchunhyang Cheonan Hospital, University of Soonchunhyang College of Medicine, Cheonan, Korea.
5. Department of Pediatrics, Pusan National University Yangsan Hospital, Yangsan, Korea.
6. Department of Pediatrics, Chung-Ang University Hospital, Gwangmyeong, Korea.
7. Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
8. Department of Pediatrics, CHA Gangnam Medical Center, CHA University School of Medicine, Seoul, Korea.
9. Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea.
10. Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.