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Calcium Levels Linked to Strokes

Victims have more calcium in their coronary arteries, study says

THURSDAY, Jan. 31, 2002 (HealthDayNews) -- Stroke victims have higher levels of calcium in their coronary arteries, raising the possibility that calcium levels could identify people at risk for strokes, new research shows.

The Dutch study, the first of its kind, appears in the February issue of Stroke: Journal of the American Heart Association.

A high level of calcium in the arteries that supply blood to the heart is an indicator of atherosclerosis, a condition marked by fatty deposits that can block blood vessels and lead to heart attacks or strokes.

Doctors already believe high levels of coronary calcification can help them predict heart attacks. However, it is not yet known whether calcification can predict heart attacks better than other known risk factors, such as high blood pressure and high cholesterol levels.

The same test that has the potential to measure coronary calcium levels as a predictor for heart attacks -- electron-beam CT scans (an ultra-fast form of X-ray) -- could also identify people at risk for stroke, the researchers say.

"Our results suggest that electron-beam CT scanning may have the potential to identify subjects at increased risk of stroke, as well as coronary heart disease," says Jacqueline C.M. Witteman, one of the study's lead investigators and an associate professor of epidemiology in the department of epidemiology and biostatistics at Erasmus Medical Center in Rotterdam, the Netherlands.

The researchers, led by Witteman and Rozemarijn Vliegenthart, also of Erasmus Medical Center, looked at 2,013 elderly residents of the city of Rotterdam, 50 of whom were stroke survivors. All underwent an electron-beam CT scan, and were assigned calcium scores based on the amount of calcium in their coronary arteries.

The relationship between calcium levels and stroke was clear: Subjects who had calcium scores between 101 and 500 were two times more likely to have suffered a stroke than those with scores between 0 and 100. And subjects who scored above 500 were three times more likely to have had a stroke, compared with subjects who scored between 0 and 100.

The findings also point to the close ties between heart disease and stroke.

"They appear to be two different manifestations of one underlying disease process, rather than two different diseases," says Dr. Lawrence M. Brass, spokesman for the National Stroke Association and a professor of neurology at Yale University School of Medicine. "These two diseases seem to be much more closely aligned than we treat them clinically."

"Our findings support the view that similar processes underlie coronary heart disease and stroke," Witteman says, and this could have important implications for how both diseases are detected.

The results may also mean stroke victims are at a higher risk for heart problems down the line.

Although Brass says he is not going to start ordering calcification tests for patients who are stroke victims, he does consider the Dutch findings a necessary wake-up call.

"After a stroke, you really need to pay a lot of attention to what's going on in the heart," he says. "We're missing an opportunity to educate and target a group at high risk for stroke to get them into the hospital in a time frame where we can make a difference."

Because this study only looked at individuals who had already had strokes, more research is needed to determine if people with high levels of calcification are at increased risk of having a stroke.

"The important question -- whether healthy subjects with a large amount of coronary calcification are at increased risk of future stroke -- still needs to be answered," says Witteman.

Using the same group of volunteers, Witteman and her colleagues are next planning to examine whether this is, in fact, the case.

What To Do: The National Stroke Association has reams of information on stroke. And check out the American Heart Association for information on heart disease.

SOURCES: Interviews with Jacqueline C.M. Witteman, Ph.D., associate professor, epidemiology, department of epidemiology and biostatistics, Erasmus Medical Center, Rotterdam, the Netherlands; Lawrence M. Brass, M.D., professor, neurology, Yale University School of Medicine, New Haven, Conn., and spokesman, National Stroke Association; February 2002 Stroke: Journal of the American Heart Association
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