1. Department of Public Health and Health Policy; Institute of Biomedical and Health Sciences; Hiroshima University; Hiroshima Japan
2. Department of Community Medicine; Chiba Medical Center; Teikyo University School of Medicine; Chiba Japan
3. Department of Community-Based Medical System; Institute of Biomedical and Health Sciences; Hiroshima University; Hiroshima Japan
4. Akimoto Occupational Health Consultant Office; Tokyo Japan