1. Center for Diagnostic and Therapeutic Endoscopy, School of Medicine, Keio University, Tokyo, Japan
2. Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan
3. Third Department of Internal Medicine, Kansai Medical University, Osaka, Japan
4. Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
5. Division of Gastroenterology, Department of Internal Medicine, School of Medicine, Iwate Medical University, Morioka, Japan
6. Department of Preventive Medicine and Public Health, Biostatistics at Center for Clinical Research, Keio University School of Medicine, Tokyo, Japan
7. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
8. Department of Gastroenterology, School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
9. Department of Endoscopy, The Jikei University School of Medicine, Tokyo, Japan
10. Department of Gastroenterology, School of Medicine, Fujita Health University, Aichi, Japan
11. Department of Gastroenterology, Nagoya Graduate School of Medicine, Nagoya, Japan
12. Comprehensive Internal Medicine, Shiga University of Medical Science, Shiga, Japan