Largest study yet ties traumatic brain injuries to later dementia risk
People with a history of traumatic brain injury are significantly more likely to develop dementia or Alzheimer’s disease compared to those with no record of TBI, according to the largest study on the subject to date.
In the report published in The Lancet Psychiatry, the researchers from the University of Washington School of Medicine examined more than 2.8 million patient records and found that those who had previously experienced a brain injury had a 24% higher risk of dementia compared to those who did not.
Approximately 50 million people worldwide experience such injuries per year, a press release from the University of Washington noted. About 47 million people worldwide suffer from dementia.
Most experts have believed TBI and dementia were closely linked, but research on the topic has been inconsistent. Now, this massive study provides strong evidence that a history of TBI does indeed increase a person’s risk for dementia later in life.
According to the report, a single severe traumatic brain injury increased the risk of developing dementia by approximately 35%. Just one “mild” TBI or concussion increased the risk by 17%.
Those who had experienced multiple traumatic brain injuries were even more in danger. People with two or more TBIs had a 33% higher risk for dementia, while those with a history of four or more TBIs had a 61% higher risk. People who had suffered five or more traumatic brain injuries saw a 183% increased chance.
“What surprised us was that even a single mild TBI was associated with a significantly higher risk of dementia,” lead author Jesse Fann said in the press release. Fann is a professor of psychiatry and behavioral sciences at the university.
“And the relationship between the number of traumatic brain injuries and risk of dementia was very clear. … Similarly, a single severe brain injury seems to have twice the risk associated with dementia as a single mild traumatic brain injury,” Fann continued.
The researchers say that when a person experienced a concussion was also a significant factor contributing to an increased risk of developing dementia. For example, a person in the 20’s who suffered a brain injury may be 60% more likely to develop dementia or Alzheimer’s in their 50’s.
Study co-author Jakob Christensen noted this is particularly worrying because traumatic brain injuries are more common in younger people.