[1] Tokyo Metropolitan Geriatr Med Ctr, Itabashi Ku, 35-2 Sakae Cho, Tokyo 1730015, Japan
[2] Sumitomo Riko Co Ltd, 3-1 Higashi, Komaki, Aichi 4858550, Japan
[3] Hirosaki Univ, Grad Sch Med, Dept Social Med, 5 Zaifu Cho, Hirosaki, Aomori 0368562, Japan
[4] Hokkaido Univ, Fac Med Dent, Dept Oral Hlth Sci, Gerontol,Kita Ku, Kita 13 Jo Nishi 7 Chome, Sapporo, Hokkaido 0608586, Japan