1. 1Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
2. 2Teikyo University Graduate School of Public Health, Tokyo, Japan
3. 3Waseda University, Saitama, Japan
4. 4The Institute of Statistical Mathematics, Tokyo, Japan
5. 5Hitachi Health Care Center, Hitachi, Ltd., Ibaraki, Japan