1. Department of Psychiatry, University of Occupational and Environmental Health, Kitakyusyu 807-8555, Japan
2. Center for Stress-related Disease Control and Prevention, University of Occupational and Environmental Health, Kitakyusyu 807-8555, Japan
3. Department of Occupational Pneumology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyusyu 807-8555, Japan
4. Department of Health Policy and Management, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyusyu 807-8555, Japan