1. School of Clinical Medicine, Ningxia Medical University, Yinchuan, Ningxia 750004, China
2. Department of Gastroenterology, People’s Hospital of Ningxia Hui Autonomous Region, Yinchuan, Ningxia 750002, China
3. Department of Gastroenterology, The Second Affiliated Hospital of Hainan Medical University, The Gastroenterology Clinical Medical Center of Hainan Province, Haikou 570216, China