1. Department of Medicine, School of Medicine, Tulane University, New Orleans, Louisiana
2. Louisiana Tumor Registry, Department of Epidemiology, Louisiana State University Health Sciences Center, New Orleans
3. University of Colorado School of Medicine and Gastroenterology of the Rockies, Denver
4. School of Public Health, Louisiana State University Health Sciences Center, New Orleans
5. Southeast Louisiana Veterans Health Care System, New Orleans
6. Division of Gastroenterology, Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana