Traumatic brain injury linked to dementia onset in seniors

Researchers report that traumatic brain injuries (TBI) in older adults are associated with new cases of dementia, use of home care services, and admission to long-term care.

The findings were published on Oct 6, 2025 in CMAJ/ Canadian Medical Association Journal.

“Although TBI has been studied as a risk factor for dementia in adulthood, our findings emphasize its significant association with an increased rate of incident dementia, even when it is sustained in late life, and how this risk changes over time,” the authors said.

As background, the authors noted, “Traumatic brain injuries are caused by a direct impact to the head or indirect force (e.g., whiplash) with one of the following: loss of consciousness, posttraumatic amnesia, disorientation, or neurological signs like slurred speech, muscle weakness, or vision changes. More than 50% of TBIs in older adults result from falls, and 1 million people in Canada over age 65 will experience a TBI in their lifetime.”

The investigators conducted a retrospective study using linked health data in Ontario, Canada, data pertaining to 264,226  community-dwelling adults older than 65 years with a new TBI between April 1, 2004 and March 1, 2020, and up to 17 years of follow-up.

Subjects, with and without a new TBI, were matched (1:1) by age, sex and propensity scoring for the analysis.

The researchers reported that a new TBI was associated with a 69% increased risk of subsequent dementia in the first 5 years, a 56% increased risk beyond 5 years, and more days of publicly funded home care (87 days compared with 84 days in people without TBI).

They found that post-TBI dementia onset was more common among older females from low-income neighborhoods than men from similar neighborhoods (29.0% v. 24.7%).

They also reported that residents of smaller communities received less post-TBI dementia onset home care than those in larger communities (60.1% v. 64.6%), and that they were more likely to get a long-term care home admission (26.3% v. 21.7%).

The authors concluded, ““Our findings suggest that, to better align limited health resources with population needs, specialized programs such as community-based dementia prevention programs, and support services should be prioritized for female older adults (≥ 75) living in smaller communities and low-income and low-diversity areas.”