1. Center for Global Health, Zhejiang University School of Medicine, Hangzhou, China
2. Department of Gastroenterology, The Third Xiangya Hospital of Central South University, Changsha, China
3. Department of Gastroenterology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
4. Centre for Global Health, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
5. Department of Gastroenterology, The Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, Hunan 410013, China