1. Hyogo Prefectural Amagasaki General Medical Center; Hospital Care Research Unit; Higashi-Naniwa-Cho 2-17-77 Amagasaki Hyogo Japan 606-8550
2. School of Public Health in the Graduate School of Medicine, Kyoto University; Department of Healthcare Epidemiology; Yoshida Konoe-cho, Sakyo-ku Kyoto Japan 606-8501
3. Shimane University; Department of Mathematics; 1060 Nishikawatsu cho Matsue 690-8504 Japan
4. Graduate School of Medicine, Kyoto University; Department of Epidemiology and Preventive Medicine; Kyoto Japan
5. Shiga University of Medical Science Hospital; Department of Anesthesia; Seta-Tsukinowa-cho Otsu Shiga Japan 520-2192