1. Department of Occupational and Environmental Medicine, Inha University Hospital, Korea.
2. Department of Preventive Medicine and Institute for Occupational Health, College of Medicine, Yonsei University, Korea.
3. Department of Occupational and Environmental Medicine, Gachon University Gil Hospital, Korea.
4. Department of Occupational & Environmental Medicine, Incheon Joongang General Hospital, Korea.
5. Center of Occupational and Environmental Medicine, lncheon Sarang Hospital, Korea.
6. Department of Preventive Medicine, Seoul National University College of Medicine, Korea.
7. Department of Internal Medicine, Inha University College of Medicine, Korea.
8. Department of Physical and Rehabilitation Medicine, Inha University College of Medicine, Korea.
9. Graduate School of Public Health and Institute for Occupational Health, Yonsei University, Korea.