1. Tokyo Metropolitan Institute for Geriatrics and Gerontology Tokyo Japan
2. Division of Preventive Dentistry, Department of Oral Health Science Graduate School of Dental Medicine, Hokkaido University Hokkaido Japan
3. Health Care and Nutritional Science Institute, Morinaga Milk Industry Co., Ltd. Kanagawa Japan
4. Department of Social Medicine Hirosaki University Graduate School of Medicine Aomori Japan
5. Gerodontology, Department of Oral Health Science, Faculty of Dental Medicine Hokkaido University Hokkaido Japan