Study Identifies Blood Fat That Increases Risk of Heart Disease
Sept. 5, 2000 -- People with higher levels of a blood fat called lipoprotein(a), or Lp(a), have a 70% greater risk of having a heart attack in 10 years than those with lower levels, according to a study in the current issue of Circulation.
"This study clearly demonstrates that Lp(a) is able to help predict who will have a heart attack," John Danesh, MBChB, DPhil, tells WebMD. He says that medical research has been confusing in this area, but more studies are now showing that this blood fat is definitely associated with a future risk of heart disease in apparently healthy people. Danesh is a clinical research fellow at Oxford University in the U.K.
The researchers looked at data from 27 different studies of more than 5,200 people who had heart disease or survived a heart attack. Over a 10-year follow-up, the participants who had higher levels of the blood fat were 70% more likely to have had heart attacks than people with lower concentrations of Lp(a) in their blood.
But "while we can now say with confidence that higher Lp(a) levels are associated with increased risk of heart disease," Danesh says that much cannot be done with this information as far as treatment. At this point, ways to effectively bring the level down are unknown.
Lp(a) is unlike "bad" cholesterol, in that it cannot be treated with medication or diet. In fact, the amount of Lp(a) in the blood is almost completely determined by genetic makeup.
So the question really is, according to American Heart Association spokesman Ronald Krauss, MD, should Lp(a) be measured? Current blood tests are not very accurate, and doctors don't know exactly how the blood fat leads to heart disease.
And as with Danesh, Krause says the lack of treatment is a hitch. "The other issue is even if we understand the impact of elevated Lp(a) on heart disease, what do we do about it?" says Krauss, who also is the head of the department of molecular medicine at the University of California at Berkeley." We don't have any effective treatments, and until we do, large scale testing is not indicated."
So is there value in the short term to the discovery? Absolutely, Krause says. "Even in the absence of treatment options, however, we might consider testing those with a family history of heart disease but who don't have any of the classical risk factors, such as high cholesterol or high blood pressure. If we can identify an elevated risk of heart disease we can be more aggressive about managing their standard risks," he says.