Eating a healthful diet and exercising can decrease the likelihood of developing diabetes and various related illnesses—cancer among them. A growing body of evidence now suggests that diabetes and conditions that predispose to it, such as high blood pressure and obesity, increase the risk of cancer. One of the most recent and largest studies to date examining this link, the National Institutes of Health–American Association of Retired Persons Diet and Health Study, has revealed that women with diabetes had an 8% increased risk of developing cancer compared to nondiabetic women, whereas for men the increase was 9%, as long as the rates of prostate cancer were excluded from the calculation. (Diabetic men have lower prostate cancer risk possibly because diabetes decreases testosterone levels.)

The researchers based these results, presented at this year's American Association for Cancer Research annual meeting in Orlando, Florida, on diet, lifestyle, and medical health data collected from more than 500,000 individuals over an 11-year period. Although the results didn't differentiate between type 1 and type 2 diabetes, type 2 is by far the most common form among Americans and is typically linked to obesity. In a related study presented at the same meeting, researchers reported that metabolic syndrome—a group of conditions including raised blood pressure, elevated waist circumference, and low “good” cholesterol—not only increases the risk of heart disease and diabetes, but may also increase the risk of the two most common types of liver cancer. Liver cancer incidence is on the rise in the United States. The study suggests that this increase may be linked to a rising incidence of metabolic syndrome, which today affects as many as 25% of Americans.

The original audio presentation of the results described above is available as part of the AACR 2011 Annual Meeting webcast.