1. Department of Gastroenterology, Qingdao University, Qingdao, China
2. Department of Gastroenterology, Qingdao Huangdao District Central Hospital, Qingdao, China
3. Department of Gastroenterology, Qingdao Municipal Hospital, Affiliated Hospital of Qingdao University, Qingdao, China
4. Department of Pathology, Qingdao Huangdao District Central Hospital, Qingdao, China
5. Department of Maternity, Qingdao Huangdao District Central Hospital, Qingdao, China