1. Division of Gastroenterology; The First Affiliated Hospital; Sun Yat-sen University; Guangzhou China
2. Department of Medicine; Yong Loo Lin School of Medicine; National University of Singapore; Singapore
3. Institute for Digestive Research; Digestive Disease Center; Soonchunhyang University Hospital; Seoul Korea
4. Division of Gastroenterology; Department of Internal Medicine; Hyogo College of Medicine; Nishinomiya Hyogo Japan
5. Division of Gastroenterology and Hepatology; Department of Internal Medicine; Keio University School of Medicine; Tokyo Japan
6. Department of Medical Statistics and Epidemiology; School of Public Health; Sun Yat-sen University; Guangzhou Guangdong China