Brain Injury May Raise Stroke Risk
Study of more than 1 million people found link but not cause and effect
By Barbara Bronson Gray
WEDNESDAY, June 26 (HealthDay News) -- People who have a traumatic brain injury may be more likely to suffer a stroke, a large new study suggests.
And while the chances of having a stroke are still small, incurring a traumatic brain injury (TBI) may be as big a risk factor as is high blood pressure, said study author Dr. James Burke.
While stroke risk is usually tied to older adults, about 20 percent occur in those under 65, said Burke, a research fellow in the neurology department at the University of Michigan Medical School. "Stroke is not typically associated with young people, and why younger people have strokes is not well understood."
But when younger adults do suffer a stroke, the effects can be daunting.
Dr. John Volpi, co-director of the Eddy Scurlock Stroke Center in Houston, recalled a patient who had a minor bike accident and seemed just fine. But after just a few days, the man -- who was only 45 -- had a stroke. "It was a slow recovery, getting back to walking and talking, and because he was an ophthalmologist, it took him a long time to be able to go back to work," Volpi said.
While study author Burke said stroke prevention has come a long way in the last 20 years or so, acute stroke treatment has seen only one significant advance, the administration of a powerful blood clot destroyer called tissue plasminogen activator (tPA).
Intravenous tPA is used in the first hours after a stroke to help break up blood clots associated with ischemic stroke, in which blood flow to part of the brain is blocked. Ischemic stroke accounts for about 87 percent of all cases, according to the American Heart Association.
"The next place to hit a potential home run [in preventing stroke] is to find other risk factors that could be playing a key role, especially in younger people," Burke said.
It is unclear how a traumatic brain injury might raise a person's stroke risk, he added. "TBI patients may have more headaches, more fear of seizures, diet changes, genuine brain rewiring, or they may be affected by the stress of TBI, or atherosclerotic plaques may be activated."
The study, published online June 26 in the journal Neurology , tapped several databases of adults in California who went to the emergency department or were discharged from a hospital between 2005 and 2009. More than 400,000 people with traumatic brain injury and more than 700,000 people with trauma but no brain injury were included in the study. The average age of all participants was about 50.
About 28 months after the injury, more than 11,000 people -- 1.1 percent -- had an ischemic stroke. But among those who had trauma but no brain injury, only 0.9 percent had a stroke. While that difference may seem small, it is significant because the overall risk of stroke for people this age is so tiny, Burke explained.