A new study finds that high blood pressure and other known risk factors for stroke also increase the risk of developing cognitive problems, even among people who have never had a stroke.
"Our results emphasize the importance of early intervention to treat high blood pressure and preserve cognitive health prior to a stroke or other cerebral event," said Frederick Unverzagt, Ph.D., a professor of psychiatry at Indiana University School of Medicine in Indianapolis. The study appears in the Nov. 8, 2011 issue of Neurology.
Strokes, which affect some 795,000 Americans each year, occur when blood vessels that supply the brain rupture or become blocked. A stroke can cause a host of cognitive disabilities, including effects on memory, speech and language, and everyday problem solving.
But even without suffering a stroke, individuals at risk for stroke may experience cognitive problems as their blood vessels deteriorate.
30,000 people
The new findings come a study that tracked stroke risk and cognitive health in an ethnically and demographically diverse sample of the U.S. population 45 and older. Since 2003, the study has followed more than 30,000 people.
Researchers collected data on nearly 24,000 study participants who had no history of cognitive impairment or stroke, and no evidence of stroke during the study.
At the start, the researchers assessed each person's stroke risk with the Framingham Stroke Risk Profile, which incorporates risk factors including age, high blood pressure, diabetes and heart problems.
"A strength of this study is that it looked at people who were cognitively healthy at the start and reassessed their cognitive function periodically to see who developed problems over time," said Walter Koroshetz, M.D. "This allowed the investigators to explore whether certain risk factors were predictive of, rather than just correlated with, cognitive impairment."
They also assessed cognitive health with a six-item screening test that required participants to give the year, month and day, and to remember three items from a list after a short delay. The test was repeated annually, and the average follow-up time was 4.1 years.
Cognitive impairment
Over the course of the study, 1,907 people without an evident stroke showed cognitive impairment, which was significantly associated with their baseline Framingham score.
The study is funded by NIH's National Institute of Neurological Disorders and Stroke (NINDS) and is led by George Howard, Ph.D., chair of the biostatistics department at the University of Alabama at Birmingham.
