1. Division of Gastroenterology and Hepatology Stanford University Medical Center Palo Alto California USA
2. Department of Medicine, Yong Loo Lin School of Medicine National University of Singapore Singapore Singapore
3. Division of Gastroenterology and Hepatology, Department of Medicine National University Health System Singapore Singapore
4. Division of Gastroenterology and Hepatology Veterans Affairs Palo Alto Health Care System Palo Alto California USA
5. Department of Epidemiology and Population Health Stanford University Medical Center Palo Alto California USA