1. Department of Gastroenterology, State Key Laboratory for Digestive Health, National Clinical Research Center for Digestive Diseases, Beijing Friendship Hospital, Capital Medical University , Beijing 100050 , China
2. Department of Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong , Hong Kong SAR , China
3. Department of Gastroenterology, Qilu Hospital of Shandong University , Jinan 250012, Shandong , China