1. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Inflammatory Bowel Disease Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea.
4. Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.
5. Division of Gastroenterology, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
6. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
7. Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
8. Institute for Evidence-Based Medicine, Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.