[1] Tokyo Womens Med Univ, Med Ctr E, Dept Med, Div Neurocardiol & Chronoecol, Tokyo 1168567, Japan
[2] Osaka Med Univ, Dept Internal Med, Osaka, Japan
[3] Kochi Univ, Sch Med, Dept Gerontol, Kochi 780, Japan
[4] Kyoto Univ, Grad Sch Med, Dept Field Med, Kyoto 606, Japan
[5] Res Inst Human & Nat, Kyoto, Japan
[6] Kyoto Univ, Ctr SE Asian Studies, Kyoto, Japan
[7] Sorachi Hlth & Welf Off, Iwamizawa, Hokkaido, Japan
[8] Yamaguchi Univ, Sch Med, Fac Hlth Sci, Div Clib Lab Sci, Ube, Yamaguchi 755, Japan
[9] Univ Minnesota, Halberg Chronobiol Ctr, Minneapolis, MN USA
[10] Tokyo Metropolitan Geriatr Hosp, Tokyo 173, Japan