This week has seen several reports in the news about concussion in sport and dementia. The newspapers were running stories about former England football star Jeff Astle, a prolific headerer of the ball, who died of early-onset dementia in 2002. His family are calling for more to be done to address the potential danger of head impact during sport.
Former England Rugby Union Centre Shontayne Hape also spoke out in the New Zealand Herald about retiring from rugby at the age of 33 following multiple concussions. He wrote about an attitude to keep playing despite repeated heavy knocks to the head and his concerns about dementia later in life.
So what do we know about a link between sports, head injury and dementia?
In a week where millions tuned in to watch Carl Froch knock out George Groves with a right cross in the eighth round, it is from the field of boxing that the strongest evidence comes linking repeated head injuries to dementia.
Protecting the welfare of the sportsmen and women we admire should be paramount.
In 1928 the term ‘punch-drunk’ was coined to describe physical and psychiatric symptoms experienced by some boxers following years in the ring. Later the term ‘dementia pugilistica’ was used to describe these symptoms in boxers. Since the 1960s, the term chronic traumatic encephalopathy (CTE) has been used to describe long-term neurological side-effects of repeated head injuries sustained in any context, not just boxing.
CTE is thought to exhibit a distinct pattern of changes in the brain. While these share some similarities with Alzheimer’s, such as the build-up of abnormal tau protein, the changes in CTE appear unique compared to other causes of dementia. Because the symptoms of CTE overlap so much with other dementias, a diagnosis of CTE is currently not possible during life – only at post-mortem.
The evidence of CTE among professional boxers has led to calls from some for a ban on the sport. Prof John Hardy, a member of our Scientific Advisory Board, voiced his concerns on boxing and CTE in an article for the New Scientist last year.
A US study called the Professional Fighters Brain Health Study is getting under way in the US to follow 400 active and retired professional boxers to find out more about the effect of the sport on the brain.
American football and dementia risk
American football is another high contact, high speed sport where professional players often experience multiple concussions. It is also a sport where research into dementia risk is under way.
Several studies of players in the American National Football League (NFL) have made the headlines in recent years, including one which reported a higher risk of Alzheimer’s and motor neurone disease. This risk was highest for players in speed positions who tended to receive high velocity impacts.
While many of these studies rely on notoriously unreliable self-reporting of head injuries, and do not prove a cause and effect relationship between concussion and neurodegenerative disease, the findings highlight the need for more to be known about potential risks associated with sport at this level.
Rugby and football and dementia risk
Rugby and football (or soccer) have received comparatively less focus in terms of research. Few, if any, studies have focused on rugby players and those looking at heading the ball in football have not shown clear evidence of a link to dementia later in life.
A small study carried out in the UK this year, which contacted Former Player Associations from four clubs in the UK, did not report a higher risk of memory and thinking problems for those who headed the ball more often. An older US study suggested that head injury symptoms in younger football players were associated with a prior acute head injury rather than an inclination to head the ball on the pitch. However, it’s widely accepted that high-quality research is lacking in this area.
Looking to the future
Many contact sports have seen improvements in safety measures over the last few decades, but calls are being made for more to be done. Last Thursday, President Obama hosted a conference on youth sport safety and the dangers of concussion, highlighting the need for ‘more data’ to fully understand the risks.
At the end of last year, the Rugby Football Union in the UK set up a working group to look into multiple concussions and dementia risk, and brought mandatory concussion training into the English professional rugby game.
We all want to continue to enjoy sport, but protecting the welfare of the sportsmen and women we admire should be paramount. More focus on research by sport governing bodies is an important step in the right direction, to make sure we understand if and when risks exist, and how best to protect against them.