Large data study finds cancer risk higher among diabetics, especially women

Aug 6, 2018

A new mashup of 47 studies of diabetes and cancer covering more than 19 million patients finds a seriously higher risk of developing cancer among diabetics, especially type 2 diabetics. It also finds diabetic women are much more likely to develop cancer than diabetic men.

The numbers are stark: women with diabetes are 27 percent more likely to develop cancer than women without diabetes. For men, the risk is 19 percent higher.

Roswell Park Oncology Associate Professor Chi-Chen Hong said the results show how important it is to include women in health studies.

"It's really important to sort of delve into it deeper, because sometimes you have to alter the way you treat men and women just because the underlying relationships are different," Hong said.

There is so much medical interest in this issue, that underlying health issues are being studied.
"We actually have a specific study looking at obesity and some of the chronic conditions related to obesity, like diabetes and hypertension," she said. "In all of the effects of breast cancer outcomes, particularly in African Americans for that population, the rates of obesity and diabetes are much higher."

Hong said women don't receive the same level of care for diabetes as men.

Chi-Chen Hong, PhD
Credit Roswell Park Comprehensive Cancer Center

"Women have higher rates of obesity than men, but it's interesting, because men are more prone to diabetes than women because they don't have to be as much overweight to be diagnosed with diabetes," Hong said. "But I think what's really kind of interesting - and it doesn't directly come from this study - is that when women do get diabetes, they actually do worse than men."

One area being studied is whether changing treatments for diabetes might have an impact on the rate of cancer among diabetics.

There is also the medical anomaly of metformin, a drug for diabetes treatment that has been around so long it is off patent and available in pharmacies. Diabetics who take metformin are less likely to develop cancer than other diabetics. Why remains unclear.

Hong said there are enough of these cases locally that Roswell Park is looking into diabetes care, to see if better management by the primary care doctor can help ease rates of cancer.