1. Division of Gastroenterology, VA San Diego Healthcare System, San Diego, CA
2. Division of Gastroenterology, University of California, San Diego, San Diego, CA
3. Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD
4. Department of Medicine, VA Tennessee Valley Healthcare System, Clinical Services Research and Development, Nashville, TN
5. Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
6. Department of Medicine, VA Geriatrics Research Education and Clinical Center (GRECC), VA Tennessee Valley Health System, Nashville, TN
7. Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN
8. Division of Biostatistics and Bioinformatics, Herbert Wertheim School of Public Health and Human Longevity Science, University of California, San Diego, San Diego, CA