1 Department of Endoscopy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei province, China.
2 Department of Nutrition, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei province, China.
3 Department of Endoscopy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei province, China. Electronic address: hbssygs@hebmu.edu.cn.