1. Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea
2. Department of Internal Medicine, School of Medicine, Kyungpook National University, Daegu, Korea
3. Department of Internal Medicine, Ewha Womans University School of Medicine, Seoul, Korea
4. Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
5. Center for Crohn's and Colitis, Department of Gastroenterology, Kyung Hee University College of Medicine, Seoul, Korea
6. Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
7. Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea
8. Division of Gastroenterology, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
9. Department of Internal Medicine, Chosun University College of Medicine, Gwangju, Korea
10. Department of Internal Medicine, Hanyang University Guri Hospital, Guri, Korea
11. Department of Public Health, Wonkwang University Graduate School, Iksan, Korea
12. Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
13. Department of Internal Medicine, Digestive Disease Research Institute, Wonkwang University College of Medicine, Iksan, Korea