Strokes steal eight years' worth of brain function, new study suggests
Having a stroke ages a person's brain
function by almost eight years, new research finds -- robbing them
of memory and thinking speed as measured on cognitive
In both black and white patients, having had a stroke meant that
their score on a 27-item test of memory and thinking speed had
dropped as much as it would have if they had aged 7.9 years
For the study, data from more than 4,900 black and white seniors
over the age of 65 was analyzed by a team from the University of
Michigan U-M Medical School and School of Public Health and the VA
Center for Clinical Management Research. The results will be
published in the July issue of Stroke.
Researchers married two sources of information for their analysis:
detailed surveys and tests of memory and thinking speed over
multiple years from participants in a large, national study of
older Americans, and Medicare data from the same individuals.
They zeroed in on the 7.5 percent of black study participants, and
the 6.7 percent of white participants, who had no recent history of
stroke, dementia or other cognitive issues, but who suffered a
documented stroke within 12 years of their first survey and
cognitive test in 1998.
By measuring participants' changes in cognitive test scores over
time from 1998 to 2012, the researchers could see that both blacks
and whites did significantly worse on the test after their stroke
than they had before.
Although the size of the effect was the same among blacks and
whites, past research has shown that the rates of cognitive
problems in older blacks are generally twice that of non-Hispanic
whites. So the new results mean that stroke doesn't account for the
mysterious differences in memory and cognition that grow along
racial lines as people age.
The researchers say the findings underscore the importance of
"As we search for the key drivers of the known disparities in
cognitive decline between blacks and whites, we focus here on the
role of 'health shocks' such as stroke," says lead author and U-M
Medical School assistant professor Deborah Levine, M.D., MPH.
"Although we found that stroke does not explain the difference,
these results show the amount of cognitive aging that stroke brings
on, and therefore the importance of stroke prevention to reduce the
risk of cognitive decline."
Other research on disparities in cognitive decline has focused on
racial differences in socioeconomic status, education, and vascular
risk factors such as diabetes, high blood pressure and smoking that
can all contribute to stroke risk. These factors may explain some
but not all of the racial differences in cognitive decline.
Levine and her colleagues note that certain factors -- such as how
many years a person has vascular risk factors, and the quality of
his or her education, as well as genetic and biological factors --
might play a role in racial differences in long-term cognitive
But one thing is clear: strokes have serious consequences for
brain function. On average, they rob the brain of eight years of
cognitive health. Therefore, people of all racial and ethnic
backgrounds can benefit from taking steps to reduce their risk of a
stroke. That includes controlling blood pressure and cholesterol,
stopping or avoiding smoking, controlling blood sugar in diabetes,
and being active even in older age.
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