[1] Tohoku Univ, Grad Sch Dent, Dept Int & Community Oral Hlth, Sendai, Miyagi, Japan
[2] Tokyo Med & Dent Univ, Grad Sch Med & Dent Sci, Dept Oral Hlth Promot, Bunkyo Ku, 1-5-45 Yushima, Tokyo 1138510, Japan
[3] Tohoku Univ, Grad Sch Dent, Div Reg Community Dev, Liaison Ctr Innovat Dent, Sendai, Miyagi, Japan
[4] Kanagawa Dent Univ, Grad Sch Dent, Dept Disaster Med & Dent Sociol, Yokosuka, Kanagawa, Japan
[5] Juntendo Univ, Dept Ophthalmol, Sch Med, Grad Sch Med,Bunkyo Ku, Tokyo, Japan
[6] Chiba Univ, Ctr Prevent Med Sci, Chiba, Japan
[7] Natl Ctr Geriatr & Gerontol, Ctr Gerontol & Social Sci, Obu, Japan