Posted on 09/22/2004 5:51:29 PM PDT by neverdem
Elevated blood sugar increases the risk of heart disease, not only in people with diabetes but also in those with high-normal readings not considered diabetic.
Two new studies provide strong evidence that the increased risk is due to blood sugar itself, independent of other problems that often go along with it, like high blood pressure and cholesterol. Before the studies, diabetes was already known to be bad for the heart: it doubles the risk of dying from cardiovascular disease, and 70 to 80 percent of people with diabetes die from heart attacks, strokes and artery disease. But researchers were not sure whether to blame blood sugar, or only the associated risk factors.
The new studies, being published today in the Annals of Internal Medicine, link blood sugar and cardiovascular disease, but do not determine whether lowering the readings can reduce the risk. More research is being done to find that out.
But in the meantime researchers say that people with diabetes, who are already advised to control blood sugar as tightly as possible, should redouble their efforts, which may include diet, exercise, weight loss and medication. And those with high-normal readings should also try to lower them, also with diet, exercise and weight loss.
The first study, done in England, looked at 10,232 people aged 45 to 79, including several hundred with diabetes. They were studied for six years and were given a test that, with one reading, reveals a person's average blood sugar for the past two to three months. The test has different versions and names: glycosylated hemoglobin, glycated hemoglobin, hemoglobin A1c or just A1c. Readings below 7 percent are considered normal, and those higher usually mean a person has diabetes.
But the researchers found trouble even at levels below 7 percent. Most people in the study had readings of 5 percent or more, and for every one percentage-point increase over 5 percent, the risk of cardiovascular problems rose 21 percent, and the risk of death increased by a similar amount. The risk from sugar held up even after the researchers accounted for blood pressure, cholesterol, obesity, smoking and previous heart attacks or strokes.
The first author of the study, Dr. Kay-Tee Khaw, of the University of Cambridge, said the study showed that average blood sugar readings may actually be too high.
The second article, by researchers at Johns Hopkins University, analyzed 13 previous studies, including 10 in people with Type 2 diabetes, the more common form of the disease (sometimes called adult onset diabetes) and three studies of Type 1 diabetes, which usually starts in childhood.
In Type 2 diabetes, for every one percentage-point increase in glycosylated hemoglobin, there was an 18 percent increase in the risk for heart disease or stroke, and a 28 percent increase in the risk for artery disease in the legs. This finding applied to any one percentage point increase, not just increases over the 5 percent level. The results were similar in Type 1 diabetes, but not statistically significant.
An author of the study, Dr. Sherita Hill Golden, said it suggested that any one percentage point lowering of glycosylated hemoglobin would help people with diabetes.
Dr. Hertzel C. Gerstein, an endocrinologist at McMaster University in Hamilton, Ontario, who wrote an editorial accompanying the studies, said that when people are having tests to assess their risk for heart disease, their A1c should be measured. The test is now used mostly to monitor treatment in people who have diabetes, and not in others. It is not used to diagnose diabetes, because it can miss early cases. But the A1c test should be used more often to gauge a patient's heart disease risk, he said. He also noted that levels are gradually increasing and Type 2 diabetes is on the rise - increases that could be reversed if people ate less, exercised more and lost weight.
Dr. Nathaniel G. Clark, national vice president for clinical affairs of the American Diabetes Association, said the idea of using A1c to help determine cardiovascular risk was "a very interesting suggestion," and the test "may go into this category of tests we don't now do, but should."
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It's not news, but it is a good article to make people aware.
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