1. Department of Work Systems and Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan;
2. Department of Epidemiology and International Health, Research Institute, International Medical Center of Japan, Tokyo;
3. Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan;
4. Asahi Kasei, Nobeoka Office Health Care Center, Miyazaki, Japan;
5. St. Mary’s Hospital, Kurume, Japan;