Absence of non-alcoholic fatty liver disease in the presence of insulin resistance is a strong predictor for colorectal carcinoma.

Background: Colorectal carcinoma (CRC) and non-alcoholic fatty liver disease (NAFLD) share common risk factors. Insulin resistance (IR) has an important role in both diseases. It has been speculated that the prevalence of colorectal neoplasms might be increased in patients with NAFLD. However, It is unclear whether NAFLD is an actual risk factor or any association is incidental coexistance due to the role of IR in both disease. We aimed to assess the risk for CRC in patients with NAFLD in relation to IR.

Method: This study was designed prospectively and cross-sectionally. We determined NAFLD by ultrasonography and measured IR by the homeostatic model of assessment-insulin resistance model.

Results: The prevalences of CRC and adenoma were shown to be significantly higher in patients with IR (respectively; P: 0.005, P: 0.008). But prevalence of CRC was found to be significantly lower in subjects with NAFLD (P: 0.001). On multivariate logistic regression analysis, the risks of colorectal adenoma and carcinoma were significantly associated with the presence of IR (respectively; OR: 2.338, 95% CI: 1.080-4.993, P: 0.003 and : 5.023, 95% CI: 1.789-9.789, P: 0.001). The risk for CRC was significantly associated with the absence of NAFLD (OR: 7.380, 95% CI: 3.069-7.961, P: 0.010). The absence of NAFLD in the presence of IR was associated with significantly high risk for CRC (OR: 5.218, 95% CI: 1.538-7.448, P: 0.017).

Conclusion: The risk of CRC can increased in subjects with IR but without NAFLD. The absence of NAFLD in the presence of IR may predict the CRC.