1. Department of Health Screening and Promotion Center, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
2. Department of Biostatistics and Clinical Epidemiology, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
3. Department of Gastroenterology, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
4. Department of Colon and Rectal Surgery, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea