1. Department of Internal Medicine and Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea
2. Department of Psychiatry, School of Medicine, Wonkwang University, Iksan, Jeollabuk-do, Korea
3. Department of Gastroenterology and Digestive Disease Research Institute, Wonkwang University School of Medicine, Iksan, Jeollabuk-do, Korea
4. Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea
5. Division of Gastroenterology, Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
6. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
7. Division of Gastroenterology, Department of Internal Medicine, Wonkwang University Sanbon Hospital, Gunpo, Gyeonggi-do, Korea