[1] St Lukes Int Hosp, Div Gen Internal Med, Dept Med, Tokyo, Japan
[2] St Lukes Int Univ, Dept Epidemiol, Grad Sch Publ Hlth, Tokyo, Japan
[3] Keio Univ, Grad Sch Business Adm, Tokyo, Japan
[4] UCLA, Div Gen Internal Med & Hlth Serv Res, David Geffen Sch Med, Los Angeles, CA USA
[5] UCLA, Fielding Sch Publ Hlth, Dept Hlth Policy & Management, Los Angeles, CA USA