Higher CRP levels in the blood may indicate that plaques in arteries are unstable and likely to break off and cause blockages. C-reactive protein may even help cause that instability, writes lead researcher Jie J. Cao, with the Henry Ford Hospital in Detroit.
In their study, Cao and colleagues identified 5,417 men and women -- all age 65 and older -- who had no stroke or heart disease problems when the study began in 1989. During the following 10 years, 469 people had what's known as ischemic stroke -- a stroke caused by a clot that blocks the carotid artery, the blood vessel that supplies the brain.
In tallying up the risk factors, researchers found that -- in addition to high blood pressure and high total cholesterol - those who had the highest CRP levels had a significantly higher stroke risk compared with those people who had the lowest levels of CRP.
And among those with high CRP levels, those who also had thicker carotid artery walls, a known risk factor for stroke and heart attacks, also were found to have a higher stroke risk.
Men were more likely to have higher C-reactive protein levels than women, which would indicate higher risk of stroke and heart disease for men, adds Cao.
The researchers conclude that high levels of CRP are a risk for stroke regardless of the thickness of the carotid artery wall. But the stroke risk was greater for those people who had both elevated CRP levels and thick artery walls.
SOURCE: Circulation: Journal of the American Heart Association, June 24, 2003.