1. Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
2. CREST, Japan Science and Technology Agency, Saitama, Japan
3. Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States
4. School of Public Health, Georgia State University, Atlanta, Georgia, United States
5. The Institute of Statistical Mathematics, Tachikawa, Japan