Study Adds to Evidence Linking Traumatic Brain Injury to Dementia Risk

By Hannah Stuart
Tuesday, September 25, 2018

Recently gathered data build on previous research associating traumatic brain injury (TBI) with development of dementia.

It has long been posited that experiencing TBI could have long-term effects, including heightened risk of developing dementia or Alzheimer’s disease. A study by researchers at the University of Washington and Aarhus University in Denmark confirms that association while also quantifying risk by the number of TBIs experienced. The research, published in The Lancet Psychiatry, examined data from Denmark’s national health registries, looking at 2.8 million patients over 36 years.

“We did find a significant association between sustaining a traumatic brain injury and the subsequent diagnosis of dementia,” says Jesse R. Fann, MD, MPH, lead author of the study and Professor in the Department of Psychology and Behavioral Sciences at University of Washington School of Medicine. “We found that overall, the risk of developing dementia among people with TBI compared to those without a history of TBI [was 24 percent higher.]”

The number of TBIs a person had experienced markedly affected risk level:

  • One TBI was linked to a 22 percent risk increase.
  • Two or three TBIs were linked to a 33 percent increase.
  • Four TBIs were linked to a 61 percent increase.
  • Five or more TBIs were linked to a nearly threefold increase.

The data expand on previous research, including a 2017 study published in PLOS ONE that suggested individuals with a history of TBI could be significantly more likely to develop dementia.

A Long-Term Perspective

“Now we need to tease out what is happening in terms of traumatic brain injury, wider-spectrum exposures and how these occur across different ages, by gender and also by community within societies,” Professor Carol Brayne from the Cambridge Institute of Public Health, University of Cambridge, wrote in a commentary regarding the research in The Lancet Psychiatry. “The attributable risk of traumatic brain injury to different exposures and how these change across time needs policy attention, given it is likely that prevention of these need be considered at societal, community and local levels.”

Knowing more about how TBI occurs may allow for the creation of initiatives to more effectively prevent it. Researchers also called for more work on approaches to treating TBI.

“Among those who sustain a TBI, are there other factors that make someone more or less prone to developing dementia?” Dr. Fann asks. “And then a follow-up to that would be, among people who have had a TBI, are there interventions — particularly early interventions — that we can provide that may be able to decrease the risk of subsequently developing dementia?”

Dr. Fann and his colleagues are conducting a multisite study that examines patients with moderate to severe TBI who are being discharged from inpatient rehabilitation. The study compares standard care to an intervention that provides telephone-based case management in an attempt to improve coordination of care.