[1] Kyoto Univ, Grad Sch Med & Publ Hlth, Dept Healthcare Epidemiol, Sakyo Ku, Yoshida Konoe Cho, Kyoto 6068501, Japan
[2] Kyoto Univ, Grad Sch Med, Human Hlth Sci, Sakyo Ku, 53 Yoshida Kawahara Machi, Kyoto 6068507, Japan
[3] Univ Tokyo, Sch Publ Hlth, Grad Sch Med, Dept Clin Epidemiol & Hlth Econ,Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan
[4] Natl Hosp Org Mito Med Ctr, Dept Emergency Med, 280 Sakuranosato, Ibaraki, Ibaraki 3113117, Japan