1. Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
2. Institute of Gastroenterology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
3. Department of Internal Medicine, Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
4. Department of Internal Medicine, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
5. Department of Gastroenterology, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Korea
6. Department of Internal Medicine, Ewha Womans University College of Medicine, Seoul, Korea
7. Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea
8. Institute for Digestive Research, Digestive Disease Center, Soonchunhyang University College of Medicine, Seoul, Korea