1. Department of Gastroenterology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Gangwon-do, Korea
2. Department of Gastroenterology, Uijeongbu Eulji Medical Center, Eulji University School of Medicine, Uijeoungbu, Gyeonggi-do, Korea
3. Departments of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
4. Departments of Biomedical Engineering, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
5. Departments of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
6. Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea