1. Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University , Zhengzhou, Henan , China
2. Department of Oncology, Weifang People’s Hospital (The First Affiliated Hospital of Weifang Medical University) , Weifang, Shandong , China
3. Department of Gastroenterology, West China School of Public Health, West China Forth Hospital, Non-communicable Diseases Research Center, West China-PUMC C.C. Chen Institute of Health, Sichuan University , Chengdu , China
4. Department of Gastroenterology, The First Affiliated Hospital of Xi ‘an Jiaotong University , Xi an , China
5. Department of Gastroenterology, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Inner Mongolia Institute of Digestive Diseases , Baotou , China
6. Department of Gastroenterology, Affiliated Hospital of Inner Mongolia Medical University , Hohhot , China
7. Department of Surgical Science, Cagliari State University , Cagliari , Italy