Affiliation: | 1. Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, , 3‐9 Fukuura, Kanazawa‐ku, Yokohama, Kanagawa 236‐0004, Japan;2. Department of Biostatistics, School of Public Health, Graduate School of Medicine, University of Tokyo, , 7‐3‐1 Hongo, Bunkyo‐ku, Tokyo 113‐0033, Japan |