1. Department of Social and Preventive Medicine, Inha University School of Medicine, Incheon, Korea.
2. Department of Occupational and Environmental Medicine, Inha University hospital, Incheon, Korea.
3. Department of Pediatrics, Inha University School of Medicine, Incheon, Korea.
4. Department of Pediatrics, Inje University Haeundae Paik Hospital, Busan, Korea.
5. Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea.
6. Department of Pediatrics, Childhood Asthma Atopy Center, Research Center for Standardization of Allergic Diseases, University of Ulsan College of Medicine, Seoul, Korea.
7. Department of Preventive Medicine, Dankook University College of Medicine, Cheonan, Korea.