1. Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Korea.
2. Department of Pediatrics, Childhood Asthma Atopy Center, Humidifier Disinfectant Health Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Pediatrics, Mediplex Sejong Hospital, Incheon, Korea.
4. Department of Pediatrics, Pusan National University Yangsan Hospital, Yangsan, Korea.
5. Department of Pediatrics, International St. Mary's hospital, Catholic Kwandong University, Incheon, Korea.
6. Department of Pediatrics, Chonnam National University College of Medicine, Gwangju, Korea.
7. Department of Pediatrics, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.