Vitamin D Deficiency Adds an Element of Risk to Insulin Resistance in Colorectal Neoplasms.

BACKGROUND

Both insulin resistance (IR) and vitamin D deficiency (VitDdef) have been suggested as risk factors for colorectal neoplasms (CRNs). However, the associations between the two with regard to CRNs are unclear.

AIMS

To determine whether IR is a risk factor for CRNs and whether VitDdef confers an additive risk of CRNs.

METHODS

Colonoscopy-naïve asymptomatic women undergoing a routine health screening program were analyzed. IR was defined as homeostatic model assessment of IR >3 and VitDdef set as <20 ng/mL. Multivariable logistic regression was performed between women with and without CRNs, matched for age and body mass index, to investigate associations with CRNs in IR, VitDdef, and VitDdef combined with IR.

RESULTS

We analyzed 216 women with CRNs and 216 without CRNs. A significant association was found between IR and CRNs (OR 1.838, 95 % CI 1.029-3.285, P = 0.040) but not with VitDdef. IR conferred a higher risk in advanced CRNs (OR 3.244, 95 % CI 1.588-6.631, P = 0.001) than CRNs. When VitDdef was combined with IR, risks of both CRNs and advanced CRNs increased (OR 2.131, 95 % CI 1.077-4.216, P = 0.030 and OR 4.438, 95 % CI 2.058-9.571, P < 0.001, respectively).

CONCLUSIONS

IR increases the risk of CRNs, and a combination of IR and VitDdef further increases this risk. As both VitDdef and IR are modifiable risk factors, such associations may have important clinical implications in the prevention of CRNs.