Participation in elite adult rugby may be associated with changes in brain structure. This is the finding of a study of 44 elite rugby players, almost half of whom had recently sustained a mild head injury while playing. The study was led by Imperial College London and published in the journal Brain Communications.

The research found a significant proportion of the rugby players had signs of abnormalities to the white matter, in addition to abnormal changes in white matter volume over time. White matter is the “wiring” of the brain and helps brain cells communicate with each other. The research team say more work is now needed to investigate the long-term effects of professional rugby on brain health.

Professor David Sharp, senior author from Imperial’s Department of Brain Sciences, says: “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. 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.”

He adds, “Our research using advanced MRI 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.”

The work, in collaboration with University College London, was funded and instigated by The Drake Foundation, who brought together academia and sport for this pioneering study.

Lauren Pulling, The Drake Foundation’s CEO, says: “At present, the long-term consequences of these brain structure abnormalities are unknown and require further research. However, taken together with existing evidence across different sports, as well as recent cases of rugby players being diagnosed with brain diseases in their 40s, they are painting a concerning picture when it comes to players’ long-term brain health.”

The study, which took place between July 2017 and September 2019, assessed 41 male players, and three female players. All underwent a brain MRI, and around half then had a second MRI scan a year later. The study used two advanced types of MRI called susceptibility weighted imaging and diffusion tensor imaging. This allowed them to look at the structure of blood vessels and the white matter. The study is the first to assess long-term changes in MRI images of professional rugby players.

The rugby players were compared to athletes in non-collision sports, as well as individuals who were not athletes. Among the group of rugby players, 21 were assessed shortly after sustaining a mild head injury, called a mild traumatic brain injury. In professional rugby union in England, these types of head injuries, which often cause concussions, are the most common reported match injury—accounting for one in five injuries.

The scientists analyzed the brain scans for changes in the white matter of the brain and compared these to the athletes in non-collision sports, and the non-athletes. The results revealed that 23% of all the rugby players showed abnormalities to their cell axons (the “wires” of brain cells), or small tears in blood vessels. These tears cause small leaks in the brain, called microbleeds.

These changes were seen in both players with and without a recent head injury. In addition, the scans provide evidence for unexpected changes in white matter volume across the whole group of rugby players. These 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.