1. Center for Gastrointestinal Biology and Disease, University of North Carolina , Chapel Hill, NC, USA
2. Department of Epidemiology, University of North Carolina , Chapel Hill, NC, USA
3. Lineberger Comprehensive Cancer Center, University of North Carolina , Chapel Hill, NC, USA
4. Department of Research and Evaluation, Kaiser Permanente Southern California , Pasadena, CA, USA
5. Department of Population Health Sciences, Duke University School of Medicine , Durham, NC, USA
6. Division of Research, Kaiser Permanente Northern California , Oakland, CA, USA
7. MedHealth Statistical Consulting Inc , Solon, OH, USA
8. Division of Hematology, Department of Medicine, University of North Carolina , Chapel Hill, NC, USA
9. Department of Obstetrics, Gynecology, and Reproductive Biology, College of Human Medicine, Michigan State University , East Lansing, MI, USA