1. Department of Pediatrics; Inje University Haeundae Paik Hospital; Busan; Korea
2. Department of Pediatrics; Korea Institute of Radiologic & Medical Science; Seoul; Korea
3. Department of Pediatrics; Asan Medical Center; College of Medicine; University of Ulsan; Seoul; Korea
4. Department of Pediatrics; Seoul National University Bundang Hospital; Seongnam; Korea
5. Department of Pediatrics; Inje University Sangge Paik Hospital; Seoul; Korea
6. Department of Pediatrics; Sacred Heart Hospital; College of Medicine; Hallym University; Bucheon; Korea
7. Department of Pediatrics; Presbyterian Medical Center; Jeonju; Korea
8. Department of Occupational & Environmental Medicine; Inha University Hospital, Incheon; Incheon; Korea
9. Department of Social and Preventive Medicine; College of Medicine; Inha University; Incheon; Korea
10. Department of Preventive Medicine; College of Medicine; Yeungnam University; Daegu; Korea
11. Department of Preventive Medicine; College of Medicine; Jeju National University; Jeju; Korea
12. Department of Occupational & Environmental Medicine; Chosun University Hospital; Gwangju; Korea
13. Department of Occupational & Environmental Medicine; Pusan National University Yangsan Hospital; Yangsan; Korea
14. Department of Preventive Medicine; College of Medicine; Dankook University; Cheonan; Korea
15. Department of Preventive Medicine; College of Medicine; Seoul National University; Seoul; Korea