1Department of Occupational & Environmental Medicine, Kosin University Gospel Hospital, Busan, Korea. kim-jongeun@hanmail.net
2Department of Preventive & Occupational Medicine, College of Medicine, Pusan University, Korea.
3Occupational Safety & Health Research Institute, KOSHA, Korea. JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/