340 High Total Cholesterol Level Increases Risk of Finding Pre-Cancerous Colonic Polyps on Initial Colonoscopies

Abstract

INTRODUCTION: The association of dyslipidemia with colorectal cancer (CRC) and pre-cancerous (PC) colon polyps has been studied with mixed results. Some studies show that high total cholesterol levels reduce the risk of PC colon polyps. A recent study showed that cholesterol influences stem cell growth in the intestines, accelerating tumor formation. We examined the association of lipid levels and statin use with PC polyp detection on initial colonoscopies. METHODS: Data were collected on 3,541 patients admitted to Louisville Veterans Affairs Medical Center, and 2,629 were excluded based on specific criteria including pro-inflammatory states postulated to increase polyposis (e.g., IBD history, pre-existing malignancies) and lack of recent lipid panel data. Of 912 patients included, 313 (34%) had high total cholesterol levels (>200 mg/dL) and 369 (40%) had history of statin use. Median age was 61, 89% patients were male, and 22% were African American. Data were gathered by retrospective chart review of the patient’s active medications and lipid levels (within 6 months) at the time of initial colonoscopy. Statin use was further stratified by duration and intensity. A Poisson Regression Model was used for analysis with upper and lower bounds, and rate ratios (RR) with corresponding P-values were calculated. Statistical significance was set at P < 0.05. Age, sex, race, smoking history and NSAID use were controlled for. RESULTS: Our study indicates that high total cholesterol levels may be associated with increased PC polyp rates. High total cholesterol level (>200 mg/dL) was associated with a 21% increase in risk of PC polyps (n = 313, RR = 1.21, P = 0.024), irrespective of statin use. Statin use in “intensity-years” (intensity multiplied by years of use) did not increase PC polyp risk, and results were statistically insignificant (n = 369, RR = 1.01, P = 0.12). Other lipid levels did not reveal statistically significant differences in PC polyp risk. CONCLUSION: Despite conflicting results of earlier studies, our study shows that high total cholesterol level may be associated with increased risk of PC polyps, irrespective of statin use. Possible mechanisms include growth of intestinal stem cells, oxidative stress, colonic inflammation, and diet associated with increased total cholesterol levels. Larger studies are needed to confirm these findings, which may have future clinical implications regarding the introduction of specific diet and lipid modification strategies to reduce CRC risk.