1. Department of Internal Medicine and Digestive Disease Research Institute, Wonkwang University School of Medicine, Iksan 54538, Republic of Korea
2. Department of Internal Medicine, College of Medicine, Chosun University, Gwangju 61452, Republic of Korea
3. Department of Internal Medicine, Research Institute of Clinical Medicine, Biomedical Research Institute, Jeonbuk National University, Jeonbuk National Medical School, Jeonju 54907, Republic of Korea
4. Department of Internal Medicine, Chonnam National University Medical School, Gwangju 61469, Republic of Korea