Study finds dementia risk increased with brain injury

A nationwide study of 2.8 million people over 36 years in Denmark has found that a person’s risk of developing dementia increases with the number and severity of traumatic brain injuries.

The study, published in The Lancet Psychiatry, found that people who sustained a traumatic brain injury were 24% more likely to be diagnosed with dementia than those without a history of traumatic brain injury over the study period. The risk of dementia increased with the number and severity of injuries, and even concussion was linked with a higher risk of dementia.

This study is one of the first of its kind to have a sufficient sample size and follow-up time to assess the effect of traumatic brain injuries in younger adults on long-term dementia risk.

Dr Doug Brown, Chief Policy and Research Officer at Alzheimer’s Society, said:

‘Over 95% of people who developed dementia in this study hadn’t had a brain injury, so the study does not tell us that traumatic brain injury is a definite cause of dementia. It does confirm earlier reports that people who have had brain injuries are at a slightly increased risk of developing the condition, but head injury is still a much smaller contributory factor for developing dementia than smoking, or a sedentary lifestyle – risk factors that are much easier for all of us to do something about.

‘There are 850,000 people with dementia – this number is set to rise to 1 million by 2021 and more research is urgently needed to fill the gaps in our understanding of lifestyle factors that increase dementia risk.’