Department of Medicine, Division of Gastroenterology, Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hills and David Geffen School of Medicine at UCLA, Los Angeles, CA. Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi, China. Departments of Medical Research. Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada. Medicine, Division of Gastroenterology, Dalin Tzu Chi Hospital, Dalin, Chiayi. Department of Medicine, Division of Gastroenterology, Tzu Chi University. Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien City, Taiwan.