Insulin resistance increases risk of colorectal adenomas

(HealthDay) -- Insulin resistance (IR) and central obesity, as measured by waist to hip ratio (WHR), are associated with a significantly increased risk of colorectal adenomas, especially in men, according to a study published in the April 1 issue of Cancer.

To investigate the association between homeostasis model assessment (HOMA)-IR and central obesity with the risk of colorectal adenoma, Ana Patricia Ortiz, M.P.H., Ph.D., of the University of Puerto Rico Comprehensive Cancer Center in San Juan, and associates prospectively collected data on lifestyle risk factors and fasting blood samples from 1,222 participants undergoing screening colonoscopies. Of the participants, 320 had incident adenomas and 902 did not.

The researchers found that, of the 1,093 participants who reported no antidiabetic medication use, those in the top quartiles of WHR and HOMA-IR were significantly more likely to have adenomas compared with those in the bottom quartiles (odds ratio [OR], 2.18 and 1.63, respectively). There was a significant interaction between HOMA-IR and gender (P_interaction = 0.04), with the correlation predominantly limited to men. Men in the top tertile of HOMA-IR were significantly more likely to have adenomas compared with those in the bottom tertile (OR, 2.11).

"Results from our screening colonoscopy-based incident cross-sectional study of adenoma support the hypothesis that IR and central obesity promote the development of early colorectal neoplasia," the authors write. "Our study highlights the fact that therapeutics or chemoprevention targeting IR may represent a novel avenue for colorectal cancer prevention."

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