[1] University of Ulsan,Department of Occupational and Environmental Medicine, Ulsan University Hospital College of Medicine
[2] Masan Samsung Hospital,Department of Occupational Medicine
[3] Ulsan University Hospital,Department of Neurology
[4] Yonsei University,Department of Occupational and Environmental Medicine, Wonju College of Medicine
[5] Korea and Occupational Safety and Health Agency,Occupational Safety and Health Research Institute
[6] University of Kentucky,Department of Preventive Medicine and Environmental Health, College of Public Health