Diabetes May Raise Colon Cancer Risk

Excess Insulin May Be to Blame

From the WebMD Archives

May 19, 2004 (New Orleans) -- Diabetes may raise the risk of developing colon cancer, the nation's second-leading cancer killer, new research shows.

"The risk factors for the two conditions are remarkably similar: obesity, sedentary lifestyles, and poor diet," says Rambabu Chalasani, MD, of Overton Brooks VA Medical Center in Shreveport, La. In the study veterans who suffered from type 2 diabetes were about one-third more likely to develop colon cancer than patients without diabetes.

The study was presented at Digestive Disease Week, a medical meeting of digestive disease experts.

"Both disorders are tied to industrialization, with the highest incidence in developed nations," he says.

A link between obesity, diabetes, and colon cancer makes sense, Chalasani tells WebMD. The common culprit: too much insulin in the blood.

As a person becomes more overweight, his or her body becomes resistant to insulin. To compensate, the body makes more and more of the sugar-lowering hormone. There is now mounting evidence that insulin stimulates the growth of cancer cells, he says.

Another Reason to Eat Right, Exercise More

Bernard Levin, MD, vice president for cancer prevention at the M.D. Anderson Cancer Center of the University of Texas in Houston, notes that this isn't the first time that diabetes has been linked with colon cancer. "But for some reason the word is not getting out; not enough people, including doctors, are aware of the [possible link]," he says.

A link between diabetes, colon cancer, and obesity would have major implications for our health, researchers agree.

People with diabetes should probably get screened for colon cancer at an earlier age and be tested more often than people without the blood sugar disorder, Levin tells WebMD.

He also says if the link exists then there are implications for what we eat and what we do. Processed and sugary foods such as cakes, cookies, and candies cause blood sugar levels to spike -- causing our body to make more insulin -- and should probably be avoided. Instead, try whole grains, vegetables, and nuts, says Levin. These foods help stabilize blood sugars causing them to rise more slowly.

And of course, get active. Exercise not only helps to shed unwanted pounds, but the weight loss also helps lower insulin levels.

The American Cancer Society recommends exercising at least 30 minutes on five or more days of the week - and walking and gardening count. Speak with your health care provider before starting an exercise program if you have diabetes and heart disease.

Excess Drinking Also a Risk Factor

In the study, the researchers evaluated the medical records of 50,697 patients between October 1998 and June 2003; about one-fifth suffered from type 2 diabetes. After taking into account colon cancer risk factors such as obesity, smoking, use of aspirin, and alcohol consumption, their study showed that those who had type 2 diabetes were a third more likely to develop colon cancer, compared with people without type 2 diabetes.

They also found that excess intake of alcohol raised the risk of colon cancer by about one-third and obesity increased the risk by about one-fourth.

Nearly 150,000 American will develop colon cancer this year, many cases of which could have been prevented through simple lifestyle changes, according to the cancer society.

Show Sources

SOURCES: Digestive Disease Week 2004, New Orleans, May 16-20, 2004. Rambabu Chalasani, MD, ER/acute care physician, Overton Brooks VA Medical Center, Shreveport, La. Bernard Levin, MD, Vice President for Cancer Prevention, M.D. Anderson Cancer Center, University of Texas, Houston. American Cancer Society web site.
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