Rising blood sugar increases risk of cardiac disease, death

Studies show importance of factor for diabetics and non-diabetics, at all levels

September 21, 2004|By Jonathan Bor | Jonathan Bor,SUN STAFF

Rising levels of blood sugar can subject diabetics and nondiabetics alike to a greater risk of cardiovascular disease and death, according to two studies being released today.

Reports in Annals of Internal Medicine suggested that doctors evaluate blood sugar alongside cholesterol and blood pressure in assessing a person's risk of heart disease.

What's more, researchers said, the current epidemic of diabetes among both children and adults could foretell an epidemic of heart disease in years to come unless people take aggressive steps to control their blood sugar.

"But this epidemic is not inevitable - it may be thwarted if we take action now," Dr. Hertzel C. Gerstein of Canada's McMaster University wrote in an editorial accompanying the studies. People would be well-advised to start by consuming fewer calories and exercising more, he said.

In one of the articles, Johns Hopkins researchers reviewed 13 previously published studies to determine what is known about the relationship between blood sugar and heart disease in diabetics.

Putting the results together, they found that measuring glycosylated hemoglobin - the percentage of red blood cells that have a sugar attached to them - is an good predictor of heart disease risk.

The test, which averages a patient's blood sugar levels over the previous three months, is already a mainstay for determining a diabetic's risk of small blood vessel damage- the sort that can injure the kidneys, eyes and extremities.

The American Diabetes Association recommends that people achieve test results of 7 percent or lower.

In their analysis, the Hopkins researchers found that each percentage-point rise in the hemoglobin test brings an 18 percent increase in the risk for cardiovascular disease in people with Type 2 diabetes and similar increase for people with Type 1.

Although research now in progress should establish with greater certainty whether people can protect their hearts by bringing down their blood sugar levels, scientists said existing evidence points to that conclusion.

"Our results suggest that lowering glucose levels in people with diabetes will further reduce their risk of heart disease, not just microvascular disease," said Elizabeth Selvin, an epidemiologist with the Johns Hopkins Bloomberg School of Public Health and lead author of the paper.

More than 17 million people in the United States suffer from diabetes, with the incidence rising each year - a situation that experts blame on lack of exercise and diets laden with calories and sugar. Type 1 diabetes is caused by the body's inability to produce enough insulin, a hormone that breaks down sugar; type 2 stems from the body's inability to use insulin.

"From the clinical perspective, the most important point is that glucose measurements should be part of the cardiovascular disease management," said Dr. Sherita Golden, assistant professor of medicine at the Johns Hopkins medical and public health schools.

In a second study, British researchers who followed 10,000 people ages 45 to 79 found that that increases in blood sugar levels corresponded with higher rates of cardiovascular disease and death - even among people who did not have diabetes.

The scientists, from Cambridge University, found that people whose glycosylated hemoglobin tests rated 5 percent or less had the smallest risk of dying from any cause. But each one-percentage-point rise translated into a 21 percent increase in "cardiovascular events" such as chest pains or heart attack.

This was true even for people whose sugar levels still placed them in the normal range. The link occurred even among people who were not overweight or did not have high cholesterol or blood pressure.

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