1. Division of Gastroenterology and Hepatology, Stanford University Medical Center, Palo Alto, California
2. Division of General Internal Medicine, Cedars-Sinai Medical Center, Los Angeles, California
3. Division of Gastroenterology and Hepatology, Department of Medicine, National University Hospital, Singapore
4. Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
5. Division of Gastroenterology and Hepatology, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
6. Department of Epidemiology and Population Health, Stanford University School of Medicine, Palo Alto, California