1. Department of Health Management, Nishinihon Occupational Health Service Center, Kitakyushu, Japan
2. Department of Occupational Health Practice and Management, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan
3. Department of Public Health, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan
4. Department of Environmental Epidemiology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan