Suffering a severe blow to the the head on the football field really can bring on Alzheimer’s disease, according to new research.
A study of more than 2,100 dementia cases found patients who had been knocked out for more than five minutes at some point in their lives were diagnosed an average two and a half years earlier.
The devastating neurological condition had actually been confirmed by post mortem examinations of subjects, making the University of Texas Southwestern study the first analysis of its kind.
The findings come amid growing concern about the safety of professional and even school sports – especially football, which has led to the neurological condition, CTE, in NFL players like Aaron Hernandez.
People who have had severe head traumas may develop Alzheimer’s earlier, new research suggests as concerns over contact sports mount
Long term effects of head injuries could only be speculated upon in the past, because dementia can only be definitively diagnosed by an autopsy.
Dr Munro Cullum, a neuropsychologist who oversaw the study, is not calling for kids to be pulled out of contact games. He is leading a nationwide effort in the US to track concussions in youth sports.
Dr Cullum, of the University of Texas Southwestern, said: ‘We need to be aware brain injury is a risk factor, but parents shouldn’t keep their kids out of sports because they fear a concussion will lead to dementia.
‘This is a piece to the puzzle, a step in the direction of understanding how the two are linked.’
The study is one piece in a mounting pile of evidence, however, showing connections between concussions and Alzheimer’s.
Earlier this year, a study on American veterans who had sustained head injuries provided scientists with the clearest glimpse of how concussions led to brain changes associated with Alzheimer’s.
Research has shown that even lower-grade head impacts may contribute to Alzheimer’s risks, meaning that playing football or other contact sports could be a danger as well.
A recent evidence review found rugby had the most concussion rates in children over three times more than ice hockey and eight times more than American football.
Other studies show rugby related hospital emergency department attendances in the US are on the rise. In particular these are for head and face injuries which make up more than a third of cases
Some former NFL players are suspected to have sustained permanent damage to their brains from repeated head impacts.In light of that and other recent research, the NFL published its first medical guidelines for players today, in an effort to provide clearer information to protect players’ safety.
In light of that and other recent research, the NFL published its first medical guidelines for players today, in an effort to provide clearer information to protect players’ safety.
But Dr Cullum and colleagues warn they still don’t know the specific processes by which a traumatic brain injury (TBI) appears to be associated with Alzheimer’s.
They are also unable to predict in individual cases who is more likely to develop dementia later in life.
Previous studies have suggested a history of TBI can accelerate onset by up to nine years, while others have found no relationship between the two.
But those used less reliable methods to diagnose dementia, raising the possibility they included data from patients who didn’t have Alzheimer’s.
Dr Cullum said more research is now needed to answer several questions not addressed by the findings published in Neuropsychology.
These include what happens during a severe bang to the head that may contribute to dementia later in life, what other factors play a role and who is most vulnerable.
Scientists speculate that inflammation occurs in the brain following a TBI, which may set the stage for the development of neurodegeneration.
Other genetic factors and unknown triggers or risks are also believed to be involved.
But solving these mysteries may take decades given the lack of detailed TBI history being kept on many patients.
Dr Cullum said most clinical researchers are not recording thorough head injury information on participants.
This has limited the amount of in-depth conclusions to be on how TBI may affect a number of neurologic and neuropsychiatric conditions.
Some progress is being made. With Dr Cullum, other researchers from his lab are involved in studies that may help reveal the roles of brain injury in other conditions, such as depression.
These will enable scientists to assess the incidence of neurodegenerative conditions as study participants age.
In addition, the NCAA has begun collecting detailed concussion histories on 32,000 of its athletes.
Added Dr Cullum: ‘But we have to wait 40 to 50 years until those college athletes are in their 60s and 70s to study them and know the outcome. That’s going to be a long wait.
‘We need researchers now to start collecting this information as part of their routine studies. Until we have more detail, all we can look at are correlations.’
The Alzheimer’s Society has said larger scale studies of athletes are needed to clarify any link between playing sport and dementia.
It says: ‘Thousands of athletes experience traumatic brain injuries every year around the world, particularly in contact and collision sports such as boxing, American football, rugby and hockey.
‘There is increasing evidence of a link between such brain injuries and dementia. As far back as 1928, the term ‘punch drunk’ was introduced to describe a disorder of progressive dementia that was first seen in boxers. It was later called ‘dementia pugilistica’ and is known today as chronic traumatic encephalopathy (CTE).
Tests have shown that former ex-NFL star Aaron Hernandez suffered from CTE before his death, putting Americans on high alert about the long term risks of contact sports.