Elevated Cholesterol Increases Risk.

• Position: Stroke - Brief Article

While it is well-established that high blood cholesterol levels increase the risk for heart attack, their effects on stroke risk is less clear. Two studies by researchers at the Columbia Presbyterian Center of New York Presbyterian Hospital have defined a new relationship between specific components of cholesterol and stroke risk.

The first examined the relationship between apolipoproteins (specific components of cholesterol) and severely blocked carotid arteries (a condition known as carotid artery atherosclerosis, or CAA) and how this relationship may correspond with stroke risk. Specifically, the researchers looked at the ratio of apo B to apo A-I, the major components of LDL (low-density lipoprotein) and HDL (high-density lipoprotein)cholesterol, respectively. Previous studies have shown that CAA can lead to stroke.

"We were interested in seeing if apo A-I and apo B were strongly associated with CAA and, ultimately, stroke risk. If so, we would then have a good screening tool to more effectively identify individuals at increased stroke risk. And once they can be identified, early and effective interventions can be made," explains Ralph L. Sacco, associate professor of neurology and public health, Columbia University College of Physicians & Surgeons.

Five hundred and seven strokefree individuals, ranging in age from 40 to 99, were enrolled in the study. Forty-one percent were Hispanic, 28% Caucasian, and 30% African-American. (One percent did not fit any of these categories.) Women accounted for 60% of the total study population.

"We found that apolipoproteins, rather than conventional lipids and lipoproteins, may be more specific determinants of moderate to severe CAA," notes Sacco. "High levels of apolipoproteins have already been shown to be linked with...