1. Teikyo University School of Medicine, Tokyo, Japan;
2. Graduate School of Medicine, The University of Tokyo, Tokyo, Japan;
3. National Center for Global Health and Medicine, Tokyo, Japan;
4. Hyogo Medical University, Nishinomiya, Japan;
5. Graduate School of Medicine, Chiba University, Chiba, Japan;
6. Institute of Biomedical Sciences, Tokushima University, Tokushima, Japan;
7. Kyoto University Graduate School of Medicine, Kyoto, Japan;
8. Kobe University Graduate School of Medicine, Kobe, Japan;
9. Kurume University School of Medicine, Kurume, Japan;
10. Faculty of Medicine, Fukuoka University, Fukuoka, Japan;
11. Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan;
12. Keio University School of Medicine, Tokyo, Japan;
13. Department of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan;
14. Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka, Japan;