A total of 4,223 participants were selected for analysis in the present study, including 2,960 with colorectal adenomas and 1,263 with normal colonoscopy results. The basic characteristics of participants are presented in Table 1. The mean age and BMI of patients with colorectal adenomas were significantly higher than those of the controls (57.4±11.5 vs. 48.2±15.8, P < 0.001; 22.93±3.28 vs. 22.45±4.75, P = 0.001); Compared with participants without any colorectal adenomas, patients with colorectal adenomas showed larger proportions of male sex (62.05% vs. 49.56%, P < 0.001), drink (9.2% vs. 2.8%, P < 0.001), smoke (19.4% vs. 7.5%, P < 0.001), hypertension (21.2% vs. 13.4%, P < 0.001), diabetes mellitus (8.4% vs. 5.6%, P = 0.002), and dyslipidemia(70.4% vs. 58.6%, P < 0.001).
Comparison of serum lipid profiles between patients with colorectal adenomas and controls
We analyzed the serum lipid levels in patients with nonadvanced or advanced colorectal adenomas, and compared them with individuals without adenomas. As shown in Table 2, the serum levels of TC, LDL-C and TG in patients with nonadvanced or advanced colorectal adenoma were significantly higher than those in subjects without adenomas. Meanwhile, patients with nonadvanced or advanced colorectal adenomas had elevated levels of ApoB than the controls. There was no significant difference between patients with nonadvanced and advanced colorectal adenoma group in lipid and lipoprotein levels except for TG, which increased in patients with advanced colorectal adenomas.
Lipid abnormality in patients with colorectal adenomas
According to the Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults, low HDL (<1.04 mmol/L), high LDL (> 3.37 mmol/L), high TG (> 1.7 mmol/L) and high TC (> 5.17mmol/L) were regarded as major types of lipid abnormality. Multiple abnormality was defined if two or more types of lipid abnormality was occurred to a patient. The distributions of lipid abnormality in patients with colorectal adenomas were shown in Table 3. High TC was the most common type of lipid abnormality in both patients with colorectal adenomas and controls, followed by multiple abnormality in the second place. Compared with controls, a larger proportion of colorectal adenoma patients suffered from high LDL, high TG and high TC, except for low HDL. Also, multiple abnormality was more frequent in patients with colorectal adenomas than in individuals without adenomas.
Association between serum levels of lipids and occurrence of colorectal adenomas
Multivariate analysis was used to determine the association of serum levels of lipids with colorectal adenoma. As shown in Table 4, older age was the most intensive risk factor for both nonadvanced adenoma (OR, 3.16; 95% CI, 2.69 - 3.71) and advanced adenoma (OR, 3.81; 95% CI, 3.08 - 4.71). Male sex, drink and smoke were risk factors that significantly increased incidence of both nonadvanced and advanced colorectal adenoma. High TG was associated with increased risk of both nonadvanced colorectal adenoma (OR, 1.36; 95% CI, 1.13 - 1.64) and advanced colorectal adenoma (OR, 1.40; 95% CI, 1.12 - 1.75). Similar association was observed for TC. High TC appeared to be a risk factor for both nonadvanced colorectal adenoma (OR, 1.35; 95% CI, 1.11 - 1.64) and advanced colorectal adenoma (OR, 1.38; 95% CI, 1.08 - 1.76). There was no significant association between serum levels of LDL-C or HDL-C and risk of colorectal adenoma.