Michihiro Satoh1,2. 1. Division of Public Health, Hygiene and Epidemiology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan. satoh.mchr@gmail.com. 2. Department of Preventive Medicine and Epidemiology, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan. satoh.mchr@gmail.com.