Neurological disorders may raise traumatic brain injury risk in older adults
· News-MedicalFor traumatic brain injury (TBI) and certain brain diseases, it looks like the risk may go in both directions, according to a study published on June 17, 2026, in Neurology®, the medical journal of the American Academy of Neurology.
Studies have shown that having a TBI may increase the risk of developing a stroke, dementia, epilepsy or Parkinson's disease. For this new study, researchers looked at older veterans who recently had a TBI to see if they were more likely to have any of those conditions than people who did not recently have a TBI.
They found that older veterans with a recent TBI were three to four times more likely to have been diagnosed with one of the four conditions in the previous year than people of similar ages who did not have a TBI.
The study does not prove that the conditions cause an increased risk of TBI; it only shows an association.
Carrie Peltz, PhD, study author of San Francisco Veterans Affairs Health Care System, CaliforniaThese findings suggest that the period after being diagnosed with a neurological condition is an important time period for preventing TBI. Our findings raise the possibility that dementia, stroke, epilepsy and Parkinson's disease are themselves risk factors for TBI in older people. Neurological diseases often impair motor control, balance, gait, coordination and thinking skills-all of which make people more likely to fall, which is the main cause of TBI in older adults."
For the study, researchers looked at 13,801 veterans with an average age of 78 who had a recent TBI and compared them to 41,403 veterans the same age who did not have a TBI. They looked at their health records for a year before and after the TBI, or at a similar timeframe for those without TBI. People who had any of the four conditions before that time point were not included in the study.
For all four conditions, people with a TBI had a higher rate of developing the condition in the year prior than people without a TBI. For stroke, the rate was 64 cases per 1,000 person-years for people with a TBI, compared to 20 cases for those without a TBI. Person-years represent both the number of people in the study and the amount of time each person spent in the study. For dementia, the rates were 58 for those with TBI compared to 19. For epilepsy, the rates were 14 for those with TBI compared to four. And for Parkinson's disease, the rates were 10 and 3.
When researchers adjusted for other factors that could affect the risk of TBI, such as diabetes, smoking and having had a heart attack, they found that people who had a TBI were four times more likely to have been recently diagnosed with epilepsy and three times more likely to have been diagnosed with stroke, dementia or Parkinson's disease.
Peltz said not finding an increased risk of Parkinson's may be due to the short follow-up time of the study, since previous studies have found an increased risk.
"Our results argue for screening older adults for their risk of falling at the time they are diagnosed and quickly referring them to physical therapy, occupational therapy or fall prevention programs," Peltz said. "Strength and balance training, making changes at home such as adding grab bars and removing tripping hazards and reviewing medications have all been shown among older adults in general to reduce the risk of falls."
A limitation of the study is that the requirement for medical information one year after the TBI would rule out people with severe TBI leading to death within a year. In contrast, people with mild TBI who did not seek medical care were also not included. In addition, since the participants were all veterans, the results may not apply to other populations.
The study was supported by the U.S. Department of Defense.
Source:
Journal reference:
Peltz, C., et al. (2026). Neurologic Diagnoses Before and After Traumatic Brain Injury. Neurology. DOI: 10.1212/wnl.0000000000218214. https://www.neurology.org/doi/10.1212/WNL.0000000000218214