1. Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
3. Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea.
4. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Korea.
5. Division of Gastroenterology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
6. Division of Gastroenterology, Department of Medicine, Soonchunhyang University College of Medicine, Cheonan, Korea.
7. Division of Colon and Rectal Surgery, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
8. Center for Preventive Medicine and Public Health, Seoul National University Bundang Hospital, Seongnam, Korea.
9. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
10. Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Korea.