Diabetes Confers Earlier Heart Risk

Added Risk for Heart Attacks and Stroke Equivalent to Aging 15 Years

Medically Reviewed by Louise Chang, MD on June 29, 2006
From the WebMD Archives

June 29, 2006 -- Diabetes is a big risk factor for heart disease and stroke, and now new research helps quantify that risk.

A Canadian study found that, in general, people with diabetes have a risk for heart disease (such as heart attack), stroke, and death from any cause similar to someone more than a decade older but without the disease.

Those with diabetes tended to be 15 years younger than people without diabetes when they developed risk factors putting them at high risk for heart attacks and strokes.

For men with diabetes, the average age for the transition from moderate to high risk was 48. For women it was 54.

These findings are reported in the July 1 issue of the journal The Lancet.

As with people without diabetes, age was still a very important predictor of cardiovascular risk for those with diabetes. Those 40 and older tended to have a much greater risk than younger people with the disease.

"A 70-year-old with diabetes is generally going to have a higher risk than someone who is 40. And under age 40, on average, people were not at high risk," says Gillian L. Booth, MD, one of the researchers involved in the study.

Heart Attack, Stroke Risk High

Diabetes patients may also have additional risk factors for heart disease and stroke, such as obesity, high blood pressure, or abnormal cholesterol levels. As a result, more than 65% of people with diabetes end up dying from heart disease and strokes, according to the American Diabetes Association.

Because this risk is so great, aggressive treatment to lower the risk has become a mainstay of diabetes therapy in recent years.

In an effort to better understand the importance of age in heart and stroke risk among people with diabetes, Booth and colleagues from Toronto's Institute for Clinical Evaluative Sciences (ICES) conducted a population-based study looking at 379,000 people with diabetes and 9 million people without the disease. All were living in Ontario, Canada.

They used the Ontario Diabetes Database to determine whether or not someone had diabetes, but the researchers were unable to distinguish between type 1 and type 2 diabetes.

Aggressive Treatment Needed?

Type 1 diabetes is much less common, occurring in only 5% to 10% of diabetes cases in the U.S. It often first develops in children and young adults. But the majority of cases are from type 2 diabetes, which is associated with age and being overweight or obese.

The Canadian researchers found that middle-aged and older people with diabetes tended to have a high risk for heart attacks and strokes, while the risk for people under age 40 was less well defined.

Booth says the findings make it clear that most diabetes patients 40 and older would benefit from aggressive treatment to lower blood pressure and normalize blood sugar and cholesterol levels.

"At least in the short term, many people with diabetes who are younger than 40 seem to have a low to moderate absolute risk of cardiovascular disease," she says.

Looking Ahead

But Om Ganda, MD, who heads the lipid clinic at Harvard Medical School's Joslin Diabetes Center, says this may not be true in the future because people are developing type 2 diabetes at younger ages than in the past.

"Someone who develops diabetes at age 30 is more likely to have a cardiovascular risk at age 40 than someone who is diagnosed at age 37," he says.

Ganda cites a 2003 study from the CDC that found that men diagnosed with type 2 diabetes at age 40 die, on average, 11 to 18 years earlier than men without the disease. Women diagnosed at the same age die 14 to 22 years earlier than women without diabetes, according to the study.

American Diabetes Association vice president John B. Buse, MD, tells WebMD that while the benefits of aggressive treatment to prevent heart disease and strokeare clear, providing optimal preventive treatment remains a major challenge.

That is because many patients will need as many as 10 different preventive drugs, he says.

"The average person with diabetes and high blood pressure needs three blood pressure medications and daily aspirin therapy. And they may need two cholesterol medications and two or three medications to regulate blood sugar," he says.

"We are asking people who probably feel fine to take 10 drugs, and take some of them more than once a day. We are also asking them to monitor their blood sugar, be careful about what they eat, and make time for exercise. There are a lot of potential barriers," Buse says.

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SOURCES: Booth, G.L. The Lancet, July 1, 2006; vol 368: pp. 29-36. Gillian L. Booth, MD, adjunct scientist, Institute for Clinical Evaluative Sciences, Toronto. John B. Buse, MD, PhD, vice president, American Diabetes Association; director, Diabetes Care Center, University of North Carolina at Chapel Hill. Om Ganda, MD, director of the lipid clinic, Joslin Diabetes Center; associate professor of medicine, Harvard Medical School, Boston.

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