People who are admitted to hospital following a significant traumatic brain injury (TBI) are more likely to be diagnosed with dementia in later life, a new study has revealed.
The research revealed that those who were in hospital for three or more days following major TBI had a higher risk of developing dementia.
Researchers at the University of Helsinki looked at the hospital records of 31,909 Finnish people spanning a 20-year period.
The participants were aged between 25 and 64, had regular health check-ups every five years between 1992 and 2012, and were monitored for dementia diagnoses for up to five years after the study.
Nearly 700 of the participants had been hospitalised with TBI between 1970 and 2017. Out of all the participants in the study, 976 were diagnosed with a form of dementia.
This study classified people as having either major or minor TBI based on the length of their stay in hospital and whether doctors found evidence of physical damage to the brain.
The results showed that participants who were in hospital for three or more days following major TBI had a higher risk of developing dementia in later life.
This was true even when age, sex and other dementia risk factors such as excessive alcohol consumption and physical inactivity were considered.
The researchers found that people who were hospitalised for up to one day following minor TBI did not have a significantly increased risk of developing dementia.
TBI is one of 12 potentially modifiable or preventable risk factors for dementia. Others include smoking, excessive alcohol consumption and physical inactivity.
Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: “There are many different risk factors for dementia including genetics, which we cannot change, but also environmental and lifestyle factors which we may be able to influence.
“Research has highlighted traumatic brain injury as an important risk factor for dementia, but there is huge variation in the severity of these injuries and we don’t yet know the point at which they will significantly affect the long-term health of the brain or how they interact with other dementia risk factors.
“This study provides further evidence that major TBI increases dementia risk, but the findings suggest that this effect was weakened in people who were physically active and didn’t drink too much alcohol.
“The results highlight the complex nature of dementia risk and the importance of the combined effects of several factors.”
Dr Sancho also highlighted that the study does not consider the cumulative effect of repeated head impacts, which is a concern in areas including sport and domestic violence.
“The researchers only considered TBI cases requiring hospital admission in the study and did not look at the effects of smaller, more frequent head impacts,” she said.
“Alzheimer’s Research UK is currently working to identify the most important questions in how sport and head injuries can affect our brain health.
“Studies like this are crucial for informing clinicians and policymakers and to implement strategies to reduce dementia risk as much as possible.”
