Professional rugby players are at risk of abnormalities in their white matter, a new study has found.
In the first study to assess long-term changes in MRI images of professional rugby players, researchers studied 44 elite ruby players, three of whom were women. Of those, 21 had recently sustained a mild traumatic brain injury when playing.
The study, which took place between July 2017 and September 2019 as part of the Drake Rugby Biomarker Study, involved the players undergoing two types of MRI scan – susceptibility weighted imaging and diffusion tensor imaging, which enabled them to examine the structure of blood vessels and the white matter.
Half of the participants had a second scan six months later.
The scientists, led by Imperial College London, UK, analysed the brain scans for changes in the white matter of the brain, and compared these to the athletes in non-collision sports, and non-athletes.
The results showed that 23% of all of the rugby players showed abnormalities to their cell axons or small tears in blood vessels, which can cause microbleeds.
These changes were seen in both players with and without a recent head injury.
The scans also provided evidence for unexpected changes in white matter volume across the whole group of rugby players, which could indicate a longer-term effect of these abnormalities to connections in the brain.
However, further research is needed to understand the significance of these changes in brain structure.
There was no difference in brain function, measured through assessments such as memory tests, between players with abnormalities in their brain structures and players without abnormalities.
Senior author Professor David Sharp, from Imperial’s Department of Brain Sciences, said: “Despite relatively high rates of head injury and an increasing focus on prevention, there has been relatively little research investigating the long-term effects of rugby participation.
Long term impact?
“More objective measures of the effects of sporting head injuries on the brain are needed to assist with the assessment and management of individual players.
“Our research using advanced magnetic resonance imaging suggests that professional rugby participation can be associated with structural changes in the brain that may be missed using conventional brain scans.
“What is not clear at this stage is the long-term clinical impact of these changes. Further research is needed to understand the long-term implications of repeated head injuries experienced during a rugby career and to provide more accurate ways to assess risk for an individual.”
Lead author Mr Karl Zimmerman, also from Imperial’s Department of Brain Sciences, said while the implications on an individual level of the brain changes associated with elite rugby participation are unclear, it is concerning to see these changes in some of the players’ brains.
“It is important to note that our results in adult professional rugby union and league players are not directly comparable to those who play at local or youth levels,” he said.
“The overall health benefit of participating in sports and physical exercise have been well established including the reduction in mortality and chronic diseases such as dementia. Long-term studies are now needed of both active and retired rugby players to investigate the effect of participation on long-term brain health.”
The work, with University College London, was funded and instigated by The Drake Foundation, which brought together academia and sport for the study. It has additional support from the National Institute for Health Imperial Biomedical Research Centre, the UK Dementia Research Institute and the Rugby Football Union.
The study is published just days after the Digital, Culture, Media and Sports (DCMS) Committee made its recommendations following an inquiry into concussion in sport.
Zimmerman KA, Laverse E, Samra R et al. White matter abnormalities in active elite adult rugby players. Brain Communications 23 July 2021. doi:10.1093/braincomms/fcab133
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