Maintaining glycemic index may help reduce the risk, researchers write in Gastroenterology.
People with high levels of insulin and glucose are at increased risk of developing recurrent colorectal adenomas, according to researchers at the American Gastroenterological Association (AGA). Specifically, they identified elevated glucose as providing the strongest risk factor.
“This is the first study to determine whether elevated glucose or insulin as measured when or shortly after a patient has had polyps removed during a baseline colonoscopy procedure increases their risk for subsequent recurrence of precancerous growths in the colon,” says Andrew Flood, Ph.D., of the University of Minnesota and lead author of the study.
The scientists state that clinical management of glycemic control is important in reducing the risk of tumor recurrence and colorectal cancer. They report finding that subjects who had even modestly impaired fasting glucose, which is an early sign of insulin resistance, had an especially large increased risk of recurrence of polyps that are most likely to progress to invasive cancer.
Patients who had the highest levels of both insulin and glucose had an approximately 50% higher risk of colorectal tumor recurrence. The Polyp Prevention Trial, of which this study was a subset, reportedly found a recurrence for colorectal tumors of 39.6% over four years. Patients with a high concentration of glucose had more than 2.4 times increased odds of advanced tumor recurrence.
The subjects with the highest glucose concentration tended to be slightly older and have higher body mass index and waist to hip ratios, the AGA team reports. Additionally, they were more likely to be male, current smokers, and a member of a minority group and less likely to have advanced beyond a high school education.
For those without a family history of colorectal cancer, researchers observed an even greater risk with elevated concentrations of insulin and glucose compared to the overall study population.
The results of this study are published in Gastroenterology, which is a publication of the AGA Institute, the arm that runs the AGA’s practice, research, and educational programs.