1. Department of Social and Preventive Epidemiology Graduate School of Medicine The University of Tokyo Tokyo Bunkyo‐ku Japan
2. Department of Health Services Research Faculty of Medicine University of Tsukuba Tsukuba Ibaraki Japan
3. Department of Clinical Epidemiology and Health Economics Graduate School of Medicine The University of Tokyo Tokyo Bunkyo‐ku Japan
4. Department of Health Services Research Graduate School of Medicine The University of Tokyo Tokyo Bunkyo‐ku Japan