1. Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea
2. Department of Family Medicine, Jeju National University School of Medicine, Jeju, Korea
3. Department of Family Medicine, Korea University Guro Hospital, Seoul, Korea
4. Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
5. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea
6. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea