Suffering a head injury just once in your life increases the risk of developing dementia by 25 per cent, a study has found.
People with a history of more blows to the cranium are at even greater risk, with two or more head injuries more than doubling the risk of dementia within 25 years.
Women are also more susceptible than men to developing Alzheimer’s following a brain injury, and white people are more at risk than black people, data shows.
The study, published today in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association , comes as an expert found one player in every international rugby match suffers a brain injury
US-based researchers studied almost 15,000 people over a quarter of a century and obtained data on head injuries from hospital records, and any information volunteered by the participants.
They found the average risk of developing dementia increased by 44 per cent if a person suffered some form of head injury.
Specifically, the risk was 25 per cent higher following one blow and 2.14 times more likely if they suffered two or more.
Evidence showed women who hit their head at least once during the 25 year window were 69 per cent more likely to get dementia than those who had no brain injury.
For men the figure was just 15 per cent.
Black people who suffer a head injury are 22 per cent more likely to get dementia than someone who has avoided blows to the skull. For white people however, the figure is 55 per cent.
The authors are unable to explain the difference between races and genders and say more research is needed to ascertain any causal link.
‘Head injury is a significant risk factor for dementia, but it’s one that can be prevented,’ said lead investigator, Dr Andrea Schneider at the University of Pennsylvania.
‘Our findings show that the number of head injuries matter – more head injuries are associated with greater risk for dementia.
Pictured, Jack Charlton (left) and his brother, Sir Bobby (right). Both England footballing legends developed dementia. Jack died in July of last year and Sir Bobby got diagnosed three months later
A Daily Mail campaign started last year has drawn attention to the plight of dementia in football.Pictured, 28 football players who have died or been diagnosed with dementia
‘The dose-dependence of this association suggests that prevention of head injury could mitigate some risk of dementia later in life.
‘While head injury is not the only risk factor for dementia, it is one risk factor for dementia that is modifiable by behavior changes such as wearing helmets and seat belts.’
The study, published today in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, comes as an expert revealed one player in every international rugby match suffers a brain injury.
Dr Willie Stewart, a neuropathologist at the University of Glasgow, made the revelation at a parliamentary inquiry into concussion and sport and described the level of injury as unacceptable.
Dr Stewart was giving evidence to the Department of Culture Media and Sport committee, which is interviewing experts and the heads of sports’ governing bodies to establish the link with neurodegenerative diseases, such as dementia.
The academic has done pioneering work to establish a link between football and brain disease. In the round ball game, heading of the ball means former players are 3.5 times more likely to die of neurodegenerative diseases than the general public.
A Daily Mail campaign started last year has drawn attention to the plight of dementia in football.
In recent months, following the death of Nobby Stiles due to dementia, the diagnosis of Bobby Charlton and death of his brother, Jack.
In the US, repeated head injuries have been linked to chronic traumatic encephalopathy (CTE), a brain condition which has claimed the lives of many former players, including Junior Seau, Mike Webster and Ken Stabler.
The high impact collisions which are common in the support lead to repeated subconcussive hits which over time leads to solidification of some brain tissue.
It manifests itself as cognitive impairment, depression, memory loss and often impulsive behaviour. It can only be diagnosed after death and through analysis of the brain of the deceased.