Department of Medicine, Department of Veterans Affairs Medical Center, White River Junction, Vermont; Department of Epidemiology for ELB, JAB, and LM and Department of Medicine in the Division of Gastroenterology and Hepatology for JCA and DJR, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire. Electronic address: joseph.anderson@dartmouth.edu. Department of Epidemiology for ELB, JAB, and LM and Department of Medicine in the Division of Gastroenterology and Hepatology for JCA and DJR, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Department of Medicine in the Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Medicine in the Division of Gastroenterology and Hepatology, University of Colorado School of Medicine and Gastroenterology of the Rockies, Denver and Boulder, Colorado. Department of Epidemiology for ELB, JAB, and LM and Department of Medicine in the Division of Gastroenterology and Hepatology for JCA and DJR, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire. Department of Epidemiology, Rollins School of Public Health, and Winship Cancer Institute, Emory University, Atlanta, Georgia. Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio. Department of Medicine in the Division of Gastroenterology and Hepatology, University of Texas MD Anderson Cancer Center, Houston, Texas. Division of Environmental Health Sciences, University of Minnesota School of Public Health, Minneapolis, Minnesota. Interim Dean and Professor of Statistics in the College of Engineering and Mathematical Sciences, University of Vermont, Burlington, Vermont. Department of Medicine in the Division of Gastroenterology and Hepatology, University of Puerto Rico, San Juan, Puerto Rico. Minnesota Gastroenterology, P.A., Minneapolis, Minnesota. Department of Medicine in the Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Medicine, Department of Veterans Affairs Medical Center, White River Junction, Vermont; Department of Epidemiology for ELB, JAB, and LM and Department of Medicine in the Division of Gastroenterology and Hepatology for JCA and DJR, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.