A new study suggests that brain injuries in young people increases the risk of later developing dementia by more than two thirds.
Conducted by researchers from Denmark and the US, the project looked at 2.8 million people over 36 years. Those who sustained a traumatic brain injury (TBI) in their 20s were 63% more likely to develop dementia—including Alzheimer’s disease.
‘Our analysis raises some very important issues, in particular that efforts to prevent traumatic brain injury, especially in younger people, may be inadequate considering the huge and growing burden of dementia and the prevalence of TBI worldwide,’ said Jesse Fann, professor of psychiatry and behavioural sciences at the University of Washington.
The study shines more light on the growing concern around head injuries in sports such as rugby, boxing and American football, where athletes face repeated blows to the head.
More than 50 million people sustain a TBI every year and by helping to prevent head injuries the overall prevalence of dementia could be reduced—currently dementia affects 47 million people worldwide.
The study also found that even sustaining a mild TBI, such as a concussion, can increase the risk by 17%.
Dr Mahmoud Maina, a researcher at the University of Sussex, said that the findings were ‘truly novel’ because of the study’s large sample size and it reinforces the fact that head injuries in sports are ‘dangerous’ and may ‘make us susceptible to dementia’.
The risk of dementia increases with the number of TBIs and the severity of each injury, and sustaining an injury at a younger age appears to increase the risk as well.
Those who sustained a TBI in their 30s were 37% more likely to develop dementia later in life, but those who sustained TBI in their 50s were only 2% more likely to get the condition.
‘We have known for some time that there is a link between traumatic brain injury and a susceptibility to dementia or other degenerative neurological conditions, particularly as a result of repeated blows to the head. This important piece of research further strengthens this body of evidence,’ said Luke Griggs, director of communications at Headway, a brain injury association.
‘It is correct however, to reinforce the message that not everyone who sustains a traumatic brain injury will go on to develop dementia later on in life. Any research that helps us better understand the complex and varied implications of brain injury have to be welcomed.’