Visceral obesity and insulin resistance as risk factors for colorectal adenoma: a cross-sectional, case-control study

Colorectal adenoma is known to be associated with obesity, but the association between colorectal adenoma and visceral adipose tissue (VAT) area measured by abdominal computed tomography (CT) has not been documented clearly. In addition, the relationship between insulin resistance and colorectal adenomas, which underlies the mechanism that links obesity and colorectal adenoma, has not been studied extensively. The aim of this study was to examine VAT area and insulin resistance as risk factors of colorectal adenoma.

A cross-sectional, case-control study was conducted in Koreans that presented for health check-ups. Subjects underwent various laboratory tests, abdominal CT, and colonoscopy. VAT, subcutaneous adipose tissue (SAT), and homeostatic metabolic assessment (HOMA) index were evaluated as potential risk factors of colorectal adenoma in 2,244 age- and sex-matched subjects.

According to univariate analysis, the prevalences of smoking, hypertension, metabolic syndrome, and family history of colorectal cancer were higher in the adenoma group than in the normal control group. In addition, body mass index, waist circumference, triglyceride, high-density lipoprotein cholesterol, and VAT and SAT areas were significantly different in the two groups. According to the multivariate analysis adjusted for multiple confounders, VAT area was independently associated with the risk of colorectal adenoma (odds ratio (OR)=3.09, 95% confidence interval (CI): 2.19-4.36, highest quintile vs. lowest quintile). Mean HOMA index was higher in the adenoma group than in the control group (OR=1.99, 95% CI: 1.35-2.92, highest vs. lowest quintile).

Visceral obesity was found to be an independent risk factor of colorectal adenoma, and insulin resistance was associated with the presence of colorectal adenoma.