1. Department of Geriatrics Ward 2 the First Hospital of Lanzhou University Lanzhou China
2. The First Clinical Medical College Lanzhou University Lanzhou China
3. Department of Gastroenterology the First Hospital of Lanzhou University Lanzhou China
4. Gansu Key Laboratory of Gastroenterology Lanzhou University Lanzhou China
5. Department of General Surgery the First Hospital of Lanzhou University Lanzhou China