[1] Jikei Univ, Res Ctr Med Sci, Div Clin Epidemiol, Sch Med,Minato Ku, Tokyo, Japan
[2] Okinawa Miyako Hosp, Tarama Clin, Miyakojima, Okinawa, Japan
[3] Jikei Univ, Ctr Med Educ, Div Community Hlth & Primary Care, Sch Med,Minato Ku, Tokyo, Japan
[4] Univ Tsukuba, Fac Med, Dept Family Med Gen Practice & Community Hlth, Tsukuba, Ibaraki, Japan