1. Department of Internal Medicine; National Defense Medical College; Saitama Japan
2. Department of Internal Medicine; Sakura Medical Center, Toho University; Chiba Japan
3. Department of Gastroenterology and Hepatology; Tokyo Medical and Dental University; Tokyo Japan
4. Kitasato Institute Hospital Center for Advanced Inflammatory Bowel Disease Research and Treatment; Tokyo Japan
5. Department of Environmental and Occupational Health, School of Medicine; Keio University; Tokyo Japan
6. Department of Environmental and Occupational Health, School of Medicine; Toho University; Tokyo Japan
7. International University of Health and Welfare Graduate School; Tokyo Japan