1 Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94063-6341, USA. Electronic address: [email protected].
2 Veterans Administration Puget Sound Health Care System, Seattle, WA, USA; Division of Gastroenterology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
3 Division of Gastroenterology and Hepatology, Oregon Health and Sciences University, Portland, OR, USA.
4 Division of Gastroenterology, Hepatology and Nutrition, Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.