A recent study by American Cancer Society Director of Tumor Repository Peter Campbell, PhD, suggests that type 2 diabetes and insulin use are associated with an increased risk of colorectal cancer in men, but not women. Dr. Campbell is the lead author of the study titled “Prospective Study Reveals Associations between Colorectal Cancer and Type 2 Diabetes Mellitus or Insulin Use in Men,” which was published in the October issue of Gastroenterology, the official journal of the American Gastroenterological Association Institute.
Using data from 73,312 men and 81,663 women who were part of the American Cancer Society CPS II Nutrition Cohort, Dr. Campbell found that 1,567 men (227 with type 2 diabetes) and 1,242 women (108 with type 2 diabetes) were diagnosed with colon or rectal cancer by 2007. Among men, type 2 diabetes was associated with increased risk of being diagnosed with colorectal cancer compared to not having type 2 diabetes. Colorectal cancer risk was higher for those participants with type 2 diabetes regardless of whether or not they used insulin. The authors speculate that the lack of an association between type 2 diabetes and colorectal cancer risk among women might relate to improved glucose control among women with type 2 diabetes in recent years.
“While our study supports an association of type 2 diabetes with colorectal cancer incidence among men, our results also suggest that insulin use is associated with a slight, but not a substantially increased, risk of colorectal cancer among men with type 2 diabetes,” Dr. Campbell says. “Prevention strategies should emphasize adherence to guidelines intended for the general population such as smoking cessation, weight management, exercise, and regular early detection exams.