1. Department of Internal Medicine, The Armed Forces Capital Hospital, Sungnam, Republic of Korea;
2. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea, and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois;
3. Division of Gastroenterology, Department of Internal Medicine, Kwandong University College of Medicine, Koyang, and Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea;
4. Department of Medicine, CHA University, Sungnam, Republic of Korea;
5. Department of Medicine, Albert Einstein Medical Center, Philadelphia, Pennsylvania;
6. Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Republic of Korea.