Study finds clear tie between parents’ stroke history, offspring’s risk
- After accounting for risk factors, people with a parent who had a stroke by age 65 face double the risk of stroke at any age and four times the risk by age 65.
- Parental history of stroke seems as important as other traditional risk factors in gauging the likelihood of stroke.
DALLAS, March 8, 2010 — Children with a parent who had a stroke, particularly by age 65, have an increased risk of stroke, suggesting parental stroke as an important new risk marker, according to a study in Circulation: Journal of the American Heart Association.
Researchers focused on 3,443 initially stroke-free subjects, all second-generation participants in the Framingham Heart Study. The participants’ parents had reported 106 strokes by age 65, and subjects reported 128 strokes over the 40-year study.
After adjusting for conventional risk factors, people with a parent who had a stroke by age 65 had twice the risk of having one at any age and four times the risk by age 65.
“The study shows that parental stroke by age 65 is a powerful risk factor for stroke in the offspring,” says Sudha Seshadri, M.D., lead author on the research. “We believe parental history of stroke should be included with other stroke risk factors in predicting a person’s risk of stroke.”
Parental stroke history seems to be of comparable importance to risk factors like high blood pressure, she said. “And it seems to give additional information over and above those risk factors. The main caveat is that while you can measure somebody’s blood pressure, you may or may not know reliably their parental stroke status.”
Data about how parental stroke affects risk in offspring has been surprisingly inconsistent, said Seshadri.
Seshadri and her colleagues also found a link between the kinds of stroke suffered by parents and offspring, specifically with ischemic stroke. (Ischemic stroke, the most common type, results from a blockage in a blood vessel to the brain.) Seventy-four of the parents’ and 106 of the offspring’s strokes were ischemic.
“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,” said Seshadri, an investigator on the Framingham study and an associate professor in the neurology department at Boston University School of Medicine.
To rule out the possibility that the parent-offspring stroke link was due to inherited or other shared risk factors, researchers adjusted for high blood pressure, diabetes, smoking status, non-stroke cardiovascular problems, age and gender. They found the parental connection held both in offspring who had other risk factors and those who didn’t, although the effect was greatest for offspring who had other risk factors, Seshadri said.
In earlier studies comparing parental stroke history and stroke risk in offspring, data were inconsistent, possibly because they relied on patients’ or offspring’s memories or on often-incomplete public records. Framingham study data helped limit those problems because stroke occurrences were directly verified shortly after they occurred; they also include details on environmental risk factors, such as diet and smoking status.
The Framingham Heart Study is an ongoing, three-generation examination of cardiovascular disease and its risk factors. The initial group was enrolled in 1948; in 1971, the first generation of the original participants’ offspring and offspring’s spouses were enrolled.
The new research examined the difference a father’s versus a mother’s stroke would have on offspring risk. While the impact of a father’s stroke on offspring risk was weaker, it was more likely to affect both male and female offspring, the study found. For mothers who had suffered a stroke, the impact was most prominent in female offspring, Seshadri said.
“Overall, I would say regardless of your gender, parental stroke does seem to make a difference,” she said.
The study outcome needs to be verified using other methods to see how it applies to the general population, Seshadri said. The findings also need to be tested in minority populations because most of the study participants were of European ancestry.
The research emphasizes a need for people to be aware of stroke diagnoses and related details in their parents. They should be attentive to their health as it relates to stroke risk; for instance, managing diabetes or quitting smoking, Seshadri said. “This highlights the importance of addressing the risk factors you can control.”
Co-authors are Alexa Beiser, Ph.D.; Aleksandra Pikula, M.D.; Jayandra J. Himali, M.Sc.; Margaret Kelly-Hayes, D.Ed., R.N.; Stephanie Debette, M.D., Ph.D.; Anita L. DeStefano, Ph.D.; Jose R. Romero, M.D.; Carlos S. Kase, M.D.; and Philip A. Wolf, M.D. Individual author disclosures are on the manuscript.
The study was funded by the National Heart, Lung, and Blood Institute, the National Institute for Neurological Disorders and Stroke and the National Institute on Aging.
Statements and conclusions of study authors published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association’s policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.americanheart.org/corporatefunding.
NR10– 1046 (Circ/Seshadri)
Editor’s note: for more information on stroke visit: http://www.strokeassociation.org.