1. Department of Gastroenterology, Weifang People’s Hospital, The First Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China
2. School of Clinical Medicine, Shandong Second Medical University, Weifang, Shandong, China
3. School of Nursing, Shandong Second Medical University, Weifang, Shandong, China
4. Department of Pathology, Shandong University School of Basic Medical Sciences, Jinan, Shandong, China
5. Department of Occupational Diseases, Weifang People’s Hospital, The First Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China.