Soccer players' brains show damage 'probably related' to frequent heading, neurologists say
Determining if dementia is more common in soccer players than in the general population a pressing question
British researchers studying the brains of retired soccer players have discovered signs of degenerative disorders associated with repeated blows to the head.
The scientists studied 14 retired soccer players, also called footballers, with dementia and performed post-mortems on six of them after next-of-kin consented.
In a study published this week in the journal Acta Neuropathologica, the researchers say all six had signs of Alzheimer's disease and four showed damage characteristic of chronic traumatic encephalopathy (CTE).
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CTE, a form of brain degeneration, potentially contributes to dementia. Symptoms of CTE include memory loss, emotional and behavioural problems, and loss of impulse control.
"The risk of dementia in those over the age of 65 in the normal population is 1 in 14 (seven per cent)," lead author Dr. Helen Ling of University College London's Institute of Neurology said in an email.
"However, we do not know if dementia is more common among retired footballers or if these footballers would have developed dementia anyway as they age without having played. The most pressing research question is therefore to find out if dementia is more common in footballers than in the normal population."
CTE has also been reported in other contact sports, such as boxing and football, that involve frequent concussion with loss of consciousness and symptoms including worsening memory and behavioural impairments as well as loss of motor control.
In England, the death of striker Jeff Astle in 2002 at 59 focused attention on the potential long-term harm of head impacts.
Astle's daughter, Dawn, called on current players and families of players to pledge to donate their brains to medical researchers.
"If we hadn't donated dad's brain, we wouldn't know what we know now — we wouldn't know what had killed him," Dawn Astle said.
Ling's team found evidence of CTE in four of the six post-mortem cases.
"This finding is probably related to their past prolonged exposure to repetitive head impacts from head-to-player collisions and heading the ball thousands of time throughout their careers," the study's authors wrote.
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All six had signs of Alzheimer's disease and some showed blood vessel changes.
The cases all played regularly for an average of 26 years. One of the men was a committed amateur.
Of the 14 players, six reported concussion with loss of consciousness while playing once in their career.
The earliest symptoms of dementia started while they were in their 60s and they lived for an average of 10 years after symptoms emerged. Twelve out of 14 of them eventually died of advanced dementia, the researchers said.
While the study shows a potential link between soccer and CTE, Ling said more studies are needed to establish if there is a cause-and-effect relationship. It's one of the reasons researchers are seeking more brains of former players to study.
"Benefits of sports are well established for mental and physical health. There is a pressing need to identify the risk of playing football and long term degenerative brain disorder so protective strategies can be implemented," she said.
In the U.S. the NFL reached a $1-billion settlement with thousands of formers players in that country who have been diagnosed with brain injuries following concussions.
In 2015, the U.S. Soccer Federation recommended a ban on headers for players 10 and under in a bid to address concerns about the impact of head injuries. A year earlier, Canadian researchers have found a higher incidence of concussions among females than males playing the world's most popular sport.
England's Football Association said it is committed to "independent, robust and thorough" research, which it is jointly funding with the players' union.
The study was started by a psychiatrist in Swansea who monitored former soccer players who were diagnosed with dementia.
The research was funded by the UK-based not-for-profit The Drake Foundation.
With files from CBC's Amina Zafar, The Associated Press and Reuters