January 20, 2009

Study Pokes Holes In Genetic Testing For Heart Disease Risk

U.S. researchers said on Monday that a study tracking a large group of women throughout a decade cast doubt on the value of genetic testing for a certain trait linked to heart disease.

The researchers suggest that knowledge of an abnormality on chromosome 9 in many women did not improve predictions for cardiovascular illness.

Traditional risk factors such as high blood pressure, smoking, cholesterol levels, diabetes, family history of heart attack and C-reactive protein are likely better indicators of arterial inflammation, they added.

However, this common genetic trait has been shown to raise the risk for heart attack, stroke and other cardiovascular conditions, and commercial tests for it are available to consumers.

Nina Paynter of Brigham and Women's Hospital in Boston, who led the study in the Annals of Internal Medicine, told Reuters that once you already know the traditional risk factors, the additional information about the genetic variation doesn't help any.

"It doesn't improve your ability to predict," she said in a phone interview.

"It definitely suggests that as a population screening tool -- to give it to everybody and add it to what we already know -- the test for this trait by itself doesn't seem to have value," Paynter said.

More and more people are turning to genetic tests to gauge their risk for various ailments, but the value of some such tests has been unclear.

For the study, Paynter and colleagues tracked 22,129 U.S. female doctors, nurses, dentists and other health care professionals for 10 years, and determined whether they had the chromosome 9 trait through blood samples.

Women with the trait had about a 25 to 30 percent higher chance of getting cardiovascular disease, the researchers said.

Paynter said scientists have yet to pinpoint the specific gene related to the trait.

She said acknowledging that a woman had the trait did not improve the ability to predict whether she had a low, medium or high risk for heart attack, stroke, death from cardiovascular disease or other cardiovascular illness.

The study, however, did not look at whether a certain targeted group of women might benefit from such testing for this particular trait.


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