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Silent Strokes Affected 10 Percent of Study Participants

Posted on: Friday, 27 June 2008, 13:50 CDT

Ten percent of middle-aged people who took part in a recent study showed they had suffered a stroke without knowing it.

Published in the journal Stroke, the study took routine MRI scans from a group of about 2,000 people with an average age of 62. Those involved with the study were the children of participants in the Framingham study, which examines the health and habits of nearly everyone in an entire town of Massachusetts.

People in this so-called Framingham Offspring Study had medical exams every four to eight years.

Researchers noted that people with atrial fibrillation, a common type of irregular heart beat in people over 65, had more than doubled their risk of suffering from these so-called silent strokes.

"The findings reinforce the need for early detection and treatment of cardiovascular risk factors in midlife," Dr. Sudha Seshadri of Boston University School of Medicine and colleagues wrote.

"This is especially true since SCIs have been associated with an increased risk of incident stroke and cognitive impairment.”

SCIs or silent cerebral infarctions are brain injuries resulting from a blood clot that slows blood flow to the brain.

MRIs showed that 10.7 percent of participants had a stroke, but showed no symptoms. Of these, 84 percent had only a single lesion in the brain.

Researchers were able to link the increased risk of strokes to a condition known as atrial fibrillation, in which the heart's two upper chambers do not pump effectively enough to empty properly, leaving blood to pool and raising the risk of blood clots. Three to 5 percent of people over 65 have atrial fibrillation.

Scientists found other factors such as high levels of blood homocysteine, a sulfur-containing amino acid found in the blood; carotid artery disease; high blood pressure and especially high systolic blood pressure all led to an increased stroke risk.

"Although previous studies have also reported a significant association of hypertension and tHcy (total homocysteine), ours is the first study to our knowledge to demonstrate a significant relationship between atrial fibrillation and SCI," the researchers wrote.

Warning signs of a stroke include changes in balance, slurred speech or a droopy face, weakness in one side, partial vision loss and severe headache, according to the American Stroke Association.

Stroke is the No. 3 cause of death in the United States, behind heart disease and cancer.

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On the Net:

Framingham Offspring Study

Stroke

Source: redOrbit Staff & Wire Reports

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