IGF-I levels and visceral fat accumulation in colonic neoplasia.

BACKGROUND: IGF-I, visceral obesity, IGF binding protein-3 and insulin are reported to be potential risk factors for colorectal carcinogenesis. Many studies report a relation between obesity, insulin resistance and the risk of colon cancer. This study investigates the association between IGF-I levels, insulin resistance and visceral fat accumulation in patients with colon cancer and adenoma. METHODS: In this cross sectional study, 48 sequential patients were diagnosed with either colorectal adenoma or carcinoma were enrolled. The control subjects were 30 sequential subjects. Serum IGF-I, HOMA insulin resistance index and visceral fat were measured in patients with colorectal adenoma and carcinoma. RESULTS: Serum IGF-I levels were significantly higher in patients with colorectal adenoma and carcinoma compared with controls. Visceral fat accumulation was lower in colorectal carcinoma group compared with colorectal adenoma group, but no statistically significant difference was observed among them and controls. No statistically significant difference was observed in HOMA insulin resistance index, fasting insulin and fasting glucose concentrations among the three groups. No correlation was found between insulin resistance and serum IGF-I levels and visceral fat accumulation. Logistic regression analysis showed that plasma IGF-I concentration was significantly associated with colorectal adenoma and carcinoma. Body mass index and waist circumference were associated with colorectal, carcinoma but were not associated with adenoma. CONCLUSION: In our study we found that, IGF-I levels are associated with colorectal adenomas and carcinomas, independent of insulin resistance and visceral fat accumulation; supporting the hypothesis that an increase in IGF-I levels may be a factor involved in the development of colon cancer.