Family Tree Provides Marker for Stroke Risk

From the WebMD Archives

Feb. 11, 2000 (New Orleans) -- Two new studies suggest that, just as one can inherit a parent's blue eyes or black hair, that same family tree can pass along granddad's stroke. That was the conclusion of two new studies reported Friday at the 25th International Stroke Conference.

Daniel Woo, MD, assistant professor of neurology at the University of Cincinnati, tells WebMD that he and his colleagues identified "stroke families in the greater Cincinnati area." He says that among persons with a type of stroke that is caused by bleeding in the brain, 25% of those who had strokes when they were younger than 70 had at least one first-degree relative -- parent or sibling -- who'd had a stroke. He says this cohort of younger patients was "four times more likely to have multiple family members with stroke."

Zoltan Voko, MD, PhD, says data from his study of over 7,200 people aged 55 or older indicate that having one relative who had a stroke before age 65 "increases one's risk somewhat, but having two or more relatives who had stroke at a younger age doubles one's risk of stroke." Even having one or more family members with strokes after age 65 increases the risk of having a stroke. Voko tells WebMD that the Rotterdam study includes strokes caused by blood clots in the blood vessels in the brain as well as strokes from bleeding. He is with Erasmus University Medical School in Rotterdam, Netherlands.

Joseph Broderick, MD, professor of medicine at the University of Cincinnati, led a press briefing with presenters from both studies. He tells WebMD that these findings underline the need to know family history. "When you find one of these multiple-stroke families with two or three family members having stroke, I think it is advisable to pursue prevention. This is analogous to a family with a history of [colon] cancer, in which family members are urged to have a colonoscopy [screening test for colon cancer]." Broderick says that prevention should be targeted at modifying known risk factors such as smoking, high blood pressure, and diabetes.

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Woo says that in his study of strokes due to bleeding, he and his colleagues didn't adjust for these risk factors and additional research will be needed to determine whether there is a true genetic susceptibility or if these families simply have a greater preponderance of risk factors. "But even if we are really talking about risk factors such as diabetes or [high blood pressure], it is likely that there is a familial pattern that explains the higher incidence of the risk factors or, perhaps, a greater susceptibility to these factors," Woo says. In any case, he says, the take-home message is that families with a history of stroke should be offered counseling.

Monique Breteler, MD, associate professor of neurology at Erasmus University and a colleague of Voko, tells WebMD that they did control for risk factors, and after correcting for other risk factors "family history was an independent predictor of stroke."

Asked if persons with a family history of stroke should be counseled to take a more aggressive approach with risk factor management -- for example, by attempting to lower blood pressure to less than 120/80 -- Broderick says that good blood pressure control is important, but he isn't sure that there is evidence to support a "lower-is-better approach." Breteler says that her group has conducted studies that suggest "very low blood pressure is actually slightly more protective." She says that such an approach should be considered for persons with a family history of stroke.

Vital Information:

  • Two new studies show that having family members who have had a stroke increases the risk of stroke.
  • Patients should be aware of their family histories and make them known to their physician.
  • Counseling and prevention measures are recommended for patients who have more than one family member who's had a stroke.
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