1. Graduate School of Medicine and Pharmaceutical Sciences, Chiba University, Chiba, Japan
2. Futaba Clinic, Futaba-cho, Tochigi, Japan
3. Center for Preventive Medical Sciences, Chiba University, Chiba, Japan
4. Faculty of Social Welfare, Nihon Fukushi University, Chita-gun, Japan
5. Center for Well-Being and Society, Nihon Fukushi University, Chita-gun, Japan
6. Center for Gerontology and Social Science, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan