Effect of Insulin Resistance and Role of Plasma Adiponectin Level in Susceptibility to Colorectal Cancer

Despite clinical and basic different investigations, the role of plasma adipokines, such as adiponectin as a precise predictor of the risk of colorectal cancer (CRC) is still conflicting.

This study investigated the association between CRC and insulin resistance, obesity, and plasma adiponectin level for the first time in Iran.

A total of 80 subjects (including 45 CRC patients and 35 healthy individuals) were enrolled in this case-control study. Demographic, anthropometric, and clinical data were recorded, and serum levels of adiponectin, insulin, and glucose were evaluated using enzyme-linked immunosorbent assay and glucose oxidase technique, respectively. Insulin resistance index (HOMA-IR) was measured as well.

The mean±SD plasma adiponectin concentration of the CRC patients (7.98±0.64 ng/ml) was not significantly higher, compared to that in the control group (8.05±1.14 ng/mL). The mean±SD of HOMA-IR and plasma glucose levels (1.81±0.61 and 7.64±1.34 mm/L, respectively) of the CRC group were significantly higher (P<0.05), compared to the control group (1.37±0.3 and 119±1.1 mg/dL, respectively); however, plasma insulin wasn’t significantly different in the two study groups. Following the stratification of CRC patients according to the tumor site, a significantly lower level of adiponectin (7.36 ±1.1 ng/ml) (P<0.05) and a significantly higher level of HOMA-IR (2.08±0.44) were observed in patients with colon cancer (P<0.005), compared to the controls. Regression among the plasma adiponectin and the plasma insulin and HOMA was negative in the control and CRC groups.

Insulin resistance has an important role in the development of CRC, especially in genesis colon cancer, regardless of the change that it causes in plasma levels of adiponectin.