1. Department of Nursing, School of Medicine, Kurume University School of Nursing, Kurume 830-0003, Japan
2. Division of Public Health, Department of Social Medicine, Nihon University School of Medicine, Tokyo 173-8610, Japan
3. Department of Mental Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
4. Department of Internal Medicine, Univer sity of Occupational and Environmental Health, Kitakyushu 807-8555, Japan