Pre-Diabetic Changes Double Heart Disease Risk

These early blood sugar trends can be lethal, study finds

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HealthDay Reporter

MONDAY, June 18, 2007 (HealthDay News) -- Even the very earliest signs of diabetes can increase the risk of dying from heart disease, a new Australian study says.

The findings mean that many more people may be in danger from the complications of diabetes -- even before they are diagnosed with the blood sugar illness.

"This study further increases our awareness of the importance of diabetes as a risk factor, not only full-blown diabetes but also people that simply have impaired glucose tolerance," said Dr. Gregory Dehmer, professor of internal medicine at Texas A&M Health Science Center College of Medicine and director of the cardiology division at Scott & White Hospital in Temple, Texas.

"This is yet another piece of information that shows that maintaining a healthy lifestyle is extremely important to everyone," added Dehmer, who was not involved in the research. "This study emphasizes that you begin to develop the cardiovascular risks for diabetes long before you develop full-blown diabetes," he said.

The study, led by Elizabeth Bar of the International Diabetes Institute, Melbourne, is reported in the June 19 issue of the journal Circulation.

Almost 20 million people in the United States have type 2 diabetes, 6 million of whom don't know it. More than 56 million people have the condition known as pre-diabetes. Impaired glucose tolerance (IGT) is a transition state between being healthy and having diabetes.

In type 2 diabetes -- which is often linked to obesity -- either the body doesn't produce enough insulin or the cells don't respond to the insulin. Insulin is a hormone that ushers sugar out of the bloodstream and into the cells, where it is used as energy. If sustained over a period of time, high blood glucose levels can cause damage to the eyes, kidneys, nerves and heart.

It's well known that diabetes increases the risk of cardiovascular disease and of early death, but the relationship between milder blood glucose elevations and cardiovascular disease has been less clear.

For this study, researchers followed 10,429 people participating in the Australian Diabetes, Obesity and Lifestyle Study for just over five years.

All participants underwent an oral glucose tolerance test along with cholesterol and triglyceride blood measurements at the beginning of the trial.

After five years, people who had diabetes had a 2.6 times higher risk of dying from cardiac problems than healthy people. Those with impaired fasting glucose (considered "pre-diabetes") had a 2.5 times higher risk.

Diabetes and pre-diabetes together accounted for almost two-thirds of all deaths from heart disease, the researchers noted.

"This is an updated, well-done version of studies that have been done previously, which demonstrate that diabetes and pre-diabetes are strong contributors to cardiovascular disease in our society," said Dr. John Buse, president-elect for medicine and science of the American Diabetes Association and chief of the division of endocrinology at the University of North Carolina School of Medicine, Chapel Hill. "We need to redouble our efforts to take care of cardiovascular risk factors and increase physical activity and appropriate eating in these populations."

Dehmer agreed. "We have known for quite some time that diabetes is a very important and potent risk factor for cardiovascular disease. This study confirms that finding," he said. "What is new in this study is that individuals with impaired fasting glucose or those that have impaired glucose tolerance, so-called pre-diabetes, are also at increased cardiovascular risk, and it's up by approximately 50 to 60 percent compared to the control population. That is a new observation."

"It's a really important wake-up call," added Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital. "Now you don't even need to have diabetes, you can have pre-diabetes and be equally at risk for cardiovascular disease."

Although increased attention to prevention seems to be called for, it's unclear how, or even if, people with pre-diabetes should be treated.

"The study was not designed to look at treatment," Dehmer pointed out. "We don't know, at least based on this study, that their cardiovascular risk will go back down to that of a group that does not have diabetes."

More information

The American Diabetes Association has more on pre-diabetes and diabetes.

SOURCES: Gregory Dehmer, M.D., professor, internal medicine, Texas A&M Health Science Center College of Medicine and director, cardiology division, Scott & White Hospital, Temple, Texas; John B. Buse, M.D., Ph.D., president-elect for medicine and science, American Diabetes Association and chief, division of endocrinology, department of medicine, University of North Carolina School of Medicine, Chapel Hill; Suzanne Steinbaum, M.D., director of women and heart disease, Lenox Hill Hospital, New York City; June 19, 2007, Circulation

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