Regularly heading a football can lead to brain damage – similar to a traumatic brain injury – which could increase the risk of dementia, a new study has shown.
The research, carried out by a team at Columbia University, also recorded a measurable decline in brain function over two years.
‘There is enormous worldwide concern for brain injury in general and in the potential for football heading to cause long-term adverse brain effects in particular,’ said senior author Dr Michael Lipton, professor of radiology and affiliate professor of biomedical engineering at Columbia.
‘A large part of this concern relates to the potential for changes in young adulthood to confer risk for neurodegeneration and dementia later in life.’
Although previous studies have examined the effects of heading a ball at a single point in time, this is the first study to assess changes over a longer period.
The team followed 148 young amateur football players with an average age of 27 (26% women) over two years, using a specialised questionnaire to determine how often they hit the ball with their head.
This was used to categorise heading exposure into low, moderate and high risk.
The players’ memory and verbal learning skills were then assessed, and their brains scanned using diffusion tensor imaging (DTI), an MRI technique used to analyse the microstructure of the brain by tracking the movement of water through the tissue.
The results showed those that headed the ball more showed more changes in the brain and decreased function.
‘Our analysis found that high levels of heading over the two-year period [more than 1,500 headers] were associated with changes in brain microstructure similar to findings seen in mild traumatic brain injuries,’ said Dr Lipton.
‘High levels of heading were also associated with a decline in verbal learning performance. This is the first study to show a change of brain structure over the long term related to sub-concussive head impacts in football.’
Dr Lipton and his team presented the findings of their research at the annual meeting of the Radiological Society of North America (RSNA), alongside results from another study which also showed repetitive heading can affect verbal learning performance.
In this study, they compared DTI results and verbal learning in 353 amateur footballers aged between 18 and 53 (27%) female, focusing on the boundary between the brain’s grey and white matter close to the skull.
The researchers found that the normally sharp grey matter-white matter interface was blunted in proportion to high repetitive head impact exposure.
‘We used DTI to assess the sharpness of the transition from gray matter to white matter,’ said Dr Lipton. ‘In various brain disorders, what is typically a sharp distinction between these two brain tissues becomes a more gradual, or fuzzier transition.’
He added that grey matter-white matter interface integrity may play a causal role in the adverse association between repetitive head impacts and cognitive performance.
‘These findings add to the ongoing conversation and contentious debate as to whether football heading is benign or confers significant risk,’ he said.
In professional sport there is increasing concern over the effects of repeated head trauma. More than 300 players are suing Welsh Rugby Union, Rugby Football Union and World Rugby over brain damage sustained while playing.
Research is continuing into potential links between head injuries in sport and dementia.
England Football is currently trialling a ban on heading in U12 matches, and in 2021 issued guidance ‘eliminating or restricting’ heading in practice for under 12s.
Manchester United hero Gary Pallister has previously spoken about his own fears of developing dementia as a result of his career.
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