1. Department of Occupational and Environmental Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.
2. Department of Occupational and Environmental Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
3. Department of Occupational and Environmental Medicine, Hanyang University College of Medicine, Seoul, Korea.
4. Korea Workers’ Compensation & Walfare Service Incheon Hospital, Incheon, Korea.
5. Korea Workers’ Compensation & Walfare Service Ansan Hospital, Ansan, Korea.
6. Department of Preventive, Occupational & Environmental Medicine, School of Medicine, Pusan National University, Yangsan, Korea.