[1] Chiba Univ, Grad Sch Med, Dept Community Oriented Med Educ, 1-8-1 Inohana, Chiba 2608677, Japan
[2] Chiba Univ Hosp, Dept Gen Med, Chiba, Japan
[3] Juntendo Univ, Sch Med, Div Med Educ, Tokyo, Japan
[4] Kyorin Univ, Dept Emergency & Gen Med, Tokyo, Japan
[5] Jichi Med Univ, Ctr Community Med, Div Gen Med, Shimotsuke, Tochigi, Japan
[6] Mito Kyodo Gen Hosp, Dept Internal Med, Tsukuba, Japan
[7] Dokkyo Med Univ Hosp, Dept Diagnost & Generalist Med, Mibu, Tochigi, Japan
[8] Muribushi Okinawa Ctr Teaching Hosp, Okinawa, Japan
[9] Tokyo Fdn Policy Res, Tokyo, Japan