1. Department of Gastroenterology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110122, P.R. China
2. 104K class 87, The Second Clinical College, China Medical University, Shenyang, Liaoning 110122, P.R. China
3. Department of Clinical Laboratory, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi 541001, P.R. China
4. Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
5. Department of Geriatric Medicine, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110122, P.R. China