The finding means that parental stroke may be an important new risk factor for strokes, long known to be associated with high blood pressure.
Researchers studied 3,443 people who initially were stroke free and second-generation participants in the Framingham Heart Study. The participants' parents had reported 106 strokes by age 65, and offspring 128, over the 40-year study.
People with a parent who had a stroke by age 65 had twice the risk of having a stroke at any age and four times the risk by 65, after adjusting for conventional risk factors, the researchers say.
The study shows that parental stroke by age 65 is a powerful risk factor for stroke in the offspring, Sudha Seshadri, MD, associate professor of neurology at Boston University School of Medicine, says in a news release. "We believe parental history of stroke should be included with other stroke risk factors in predicting a person's risk of stroke."
Indeed, she says, parental stroke seems to be as important a risk factor as high blood pressure.
Seshadri and colleagues also report that they found a link between the kinds of strokes suffered by parents and types their offspring had.
For example, 74 parents had ischemic strokes, and 106 offspring suffered the same type of stroke event. Ischemic strokes are the most common kind, resulting from a blockage in a blood vessel to the brain.
"We looked at this in terms of what kind of stroke the parents had, what kind the children had, and it seemed to hold true across all types," Seshadri says.
Researchers found that the parental connection held true in offspring who had other risk factors and also in those who didn't, but that the effect was greatest for offspring who had other risk factors.
The Framingham Heart Study is an ongoing, three-generation research project on cardiovascular disease and its risk factors. In 1948, the initial group was enrolled, and the first generation of offspring, and their spouses, were enrolled in 1971.
The study suggests the impact of a father's stroke on offspring may be weaker than a mother's - and more likely to affect both male and female
For female stroke patients, the study suggests the impact may be most worrisome for their daughters.
The bottom line, the authors write, is that "verified parental stroke may serve as a clinically useful risk marker of an individual's propensity to stroke," regardless of gender of children.
The study is published in the March 23 issue of Circulation: Journal of the American Heart Association.
By Bill Hendrick
Reviewed by Laura Martin
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