1. Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, Korea
2. Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
3. Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea
4. Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea
5. Department of Internal Medicine, College of Medicine, Kyung Hee University, Seoul, Korea
6. Institute for Digestive Research, Soonchunhyang University Seoul Hospital, Seoul, Korea
7. Department of Internal Medicine, Ewha Medical Research Institute, Ewha Womans University College of Medicine, Seoul, Korea
8. Department of Internal Medicine, Wonkwang University School of Medicine, Iksan, Korea