ANN ARBOR, MI — People who have a traumatic brain injury may be somewhat more likely to have a future stroke, according to research by a University of Michigan Health System team that appears in the June 26, online issue of Neurology, the medical journal of the American Academy of Neurology.
“Both stroke and traumatic brain injury are common, costly, and leading causes of severe disability in adults, and approximately 20 percent of
strokes occur in adults under age 65,” said study author James F. Burke, M.D., M.S., a clinical lecturer in the U-M Medical School’s Department of Neurology and researcher at the VA Ann Arbor Healthcare System. “A large proportion of stroke risk is unexplained, especially in the young, so if we can identify new risk factors, we have the potential to prevent more strokes and improve outcomes.”
Burke is a VA research fellow in the Robert Wood Johnson Clinical Scholars Program at U-M.
For the study, researchers looked at the records of adults who went to the emergency department or were admitted to a hospital for TBI or other trauma with no brain injury in the state of California during a five-year period.
A total of 435,630 people with traumatic brain injury were studied, along with 736,723 people with trauma with no brain injury.
Over an average of 28 months following the injury, 11,229 people, or 1 percent, had an ischemic stroke. A total of 1.1 percent of those with TBI suffered a stroke, compared to 0.9 percent of those with trauma with no brain injury.
With an ischemic stroke, blood flow to part of the brain is blocked. Eighty percent of strokes are ischemic.
After adjusting for factors that can affect stroke risk, such as age, high blood pressure and high cholesterol, as well as other disorders such as heart disease and the severity of the trauma, the researchers found that people with traumatic brain injury were more likely to develop a stroke than those with trauma with no brain injury.
“While the stroke risk of one person with TBI is small, the overall link between TBI and stroke was substantial— as large as the link between the strongest stroke risk factor, high blood pressure, and stroke,” Burke said. “If further research establishes TBI as a new risk factor for stroke, that would stimulate research to help us understand what causes stroke after TBI and help us learn how to prevent these strokes.”
The study was supported by an advanced fellowship through the Department of Veterans Affairs.
The study’s other authors are Jessica L. Stulc, MD, MPH, Lesli E. Skolarus, MD, MS, Darin B. Zahuranec, MD, MS and Lewis B. Morgenstern, M.D. of the U-M Department of Neurology and Stroke Program, and Erika D. Sears, MD, MS, of the U-M DIvision of Plastic Surgery. Morgenstern also holds a joint appointment in the U-M School of Public Health.
For more information about the American Academy of Neurology, visit http://www.aan.com.