1. Institutional Improvement Committee of the Korean Society of Occupational and Environmental Medicine, Seoul, Korea.
2. Department of Occupational and Environmental Medicine, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea.
3. Department of Occupational and Environmental Medicine, Shincheon Union Hospital, Siheung, Korea.
4. Department of Occupational and Environmental Medicine, Inha University Hospital, Inha University, Incheon, Korea.
5. Department of Occupational and Environmental Medicine, Cheongju Hankook General Hospital, Cheongju, Korea.
6. Center for Occupational and Environmental Medicine, Hanil General Hospital, Seoul, Korea.
7. Department of Occupational and Environmental Medicine, Chosun University Hospital, Gwangju, Korea.
8. Department of Preventive Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.