1. Cancer Research Institute; Seoul National University College of Medicine; Seoul South Korea
2. Division of Epidemiology and Biostatistics; University of Illinois at Chicago School of Public Health; Chicago Illinois
3. Department of Preventive Medicine; Seoul National University College of Medicine; Seoul South Korea
4. Molecular Epidemiology Branch, National Cancer Center; Goyang South Korea
5. Department of Surgery; Seoul National University College of Medicine and Hospital; Seoul South Korea
6. Center for Colorectal Cancer, National Cancer Center; Goyang South Korea
7. Division of Epidemiology, Department of Medicine; Vanderbilt University School of Medicine; Nashville Tennessee