Background  Colorectal polyp is a common disease of the digestive system, but the specific formation mechanism and cause of carcinogenesis have not been fully elucidated. Some studies have found that it may be related to lipid metabolism level.

  Objective  To study the characteristics of lipid metabolism in patients with colorectal polyp.

  Methods  Patients who underwent colonoscopy in the First Medical Center of Chinese PLA General Hospital from October 1, 2021 to March 31, 2022 were selected. The subjects were divided into polyp group and control group according to whether they had polyps by colonoscopy, including 370 cases in polyp group and 48 cases in control group. The body mass index, fasting blood glucose, total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein and other lipid metabolism of patients with single or multiple colorectal polyps were retrospectively analyzed.

  Results  A total of 418 cases were included, including 257 males and 161 females, aged 19-89 (56.18 ± 11.84) years. There were 48 non-polyp control patients, 101 hyperplastic polyp patients, 213 adenomatous polyp patients, and 56 colorectal cancer patients. Compared with control group, total cholesterol level in hyperplastic polyp group increased significantly (P<0.05), fasting blood glucose and low-density lipoprotein increased significantly in adenomatous polyp group (P<0.05). Total cholesterol, triglyceride and low-density lipoprotein in colorectal cancer group were significantly lower than those in adenomatous polyp group, and total cholesterol was significantly lower than that in proliferative polyp group (P<0.05). Logistic regression showed that the risk of colorectal cancer decreased by 32% for each 1 mmol/L increase in fasting blood glucose (OR =0.680, 95%CI: 0.492-0.941, P=0.020). For each 1 mmol/L increase in triglycerides, the risk of colorectal cancer decreased by 59% (OR =0.410, 95%CI: 0.183-0.919, P=0.030). Of the 370 patients with polyps, there were no significant differences in lipid metabolism indexes among different position groups in male patients (P>0.05). In female patients, the body mass index in transverse colon polyp group was significantly lower than that in sigmoid colon group (P<0.05). The serum total cholesterol level of cecal polyp group was significantly higher than that of rectum, descending colon, transverse colon, ascending colon and ileocecal polyp group (P<0.05). The serum triglyceride level of cecal polyps was significantly higher than that of other groups (P<0.05). In male patients, the levels of total cholesterol and low density lipoprotein in multiple polyp group were significantly higher than those in single polyp group (P<0.05). There were no significant differences in lipid metabolism indexes between single and multiple polyps in female patients (P>0.05).

  Conclusion  The malignant degree of polyp was correlated with the level of serum fasting blood glucose and triglyceride. The occurrence of cecal polyp and sigmoid colorectal polyp was significantly related to the level of high lipid metabolism. The number of polyps was correlated with serum cholesterol and low density lipoprotein levels in male patients. The results suggest that the change of lipid metabolism is a potential risk factor for malignant colorectal lesions..