Diabetes may raise cancer risk -- but don't panic just yet

Diabetes may be more dangerous than we thought. New research suggests that people with diabetes are slightly more likely to die from cancer than are people without diabetes.

As if managing the laundry list of diabetes-related illnesses such as heart disease, blindness and kidney failure weren’t bad enough, it appears that women with diabetes have an 11% increased risk of dying from cancer and men have a 17% higher risk than those without diabetes. The findings were presented Sunday in Orlando, Fla., at the American Assn. for Cancer Research annual meeting.

It’s too soon to identify the precise cause of the connection. But it might be that an underlying mechanism, such as the body’s inability to control insulin, could cause both diabetes and cancer, where cells multiply like haywire into tumors. Researchers found that even after controlling for two cancer-related risk factors often found in Type 2 diabetics, obesity and cigarette smoking, diabetics are still at higher risk for cancer.

That’s not to say the risk of actually developing cancer is necessarily higher.  For men, having diabetes comes with a surprising perk – at least at first glance. Although women with diabetes have an 8% increased risk of developing cancer, men have a 4% reduced risk. But once researchers excluded prostate cancer from the mix, men had a 9% increased risk of having cancer. (Ah, statistics.) The lower rates of prostate cancer might have to do with the lower testosterone levels in diabetics, researchers believe.

For both sexes, diabetes is linked to a higher risk of colon, rectal and liver cancers, the study found. In men, risk for pancreatic and kidney cancers is higher; in women, stomach, anal and endometrial cancer (cancer in the uterus lining) risk is higher.

The results were presented by a team led by the National Cancer Institute, which tracked more than 500,000 men and women—mostly white, non-Hispanic, and between 50 and 71 years old—for 11 years. The participants filled out questionnaires about their diet, lifestyle, and whether they had diabetes. The results didn’t differentiate between Type 1 and Type 2 diabetes, but Type 2 is by far the most common form in the U.S., usually linked to lifestyle factors such as obesity.

These results echo findings last month that people with Type 2 diabetes are 25% more likely to die from cancer and twice as likely to die from heart disease than a non-diabetic. That study of more than 820,000 people pointed to kidney disease, liver disease and pneumonia as other killers associated with diabetes. The study also found a lower risk of death from prostate cancer.

Reality Check: Neither of the latest studies concludes that diabetes causes cancer. And the statistical differences were small. Very small in some cases. A 4% reduced risk of cancer in diabetic men is barely below the norm, and for one man hardly makes a difference in whether he's likely to develop cancer.

But the research drives home, yet again, the importance of preventing and controlling diabetes.

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