CTE risk increases with length of rugby career

The risk of brain disease chronic traumatic encephalopathy (CTE) increases with the length of career for Rugby Union players, a landmark international study has concluded.

In a world-first collaboration, research teams found new evidence linking playing rugby – either at amateur or elite level – with the neurodegenerative disease.

Led by Professor Willie Stewart at the University of Glasgow, the work follows findings from his group last year which reported neurodegenerative disease risk among former Scottish international rugby union players approximately two and a half times higher than expected.

Research now links CTE with head impacts and the strength and frequency with which they are sustained. There have been increasing reports of CTE in the pathology of athletes who have played football, American football, boxing and rugby.

This latest study looked at the results of detailed postmortem brain examinations of 31 former amateur and elite rugby union players whose brains were donated for research purposes to one of three leading centres in the UK, United States, and Australia.

CTE was found in around two thirds (68 per cent) of the brains examined, and in both amateur and elite players.

Importantly, risk of CTE pathology was associated with length of a player’s rugby career, with each additional year of play adding 14 per cent to risk of CTE. Player position or level of participation, either amateur or elite, did not appear to influence risk of CTE.

The current study, which is the first research collaboration between leading laboratories at the University of Glasgow, Boston University and the University of Sydney, continues Glasgow’s groundbreaking research into brain health outcomes associated with traumatic brain injury and contact sports.

Among sports, Rugby Union is known to have a high risk of mild traumatic brain injury, or concussion, with injury rates highest in the professional game. To date, the only recognised risk factor for CTE is traumatic brain injury and repeated head impact exposure.

Professor Stewart, consultant neuropathologist and Honorary Professor at the University of Glasgow, lead author of the study, said: “In this study, we have combined the experience and expertise of three leading international brain banks to look at CTE in former rugby players.

“These results provide new evidence regarding the association between rugby union participation and CTE. Specifically, our data show risk is linked to length of rugby career, with every extra year of play increasing risk.

“Based on this it is imperative that the sport’s regulators reduce exposure to repeated head impacts in match play and in training to reduce risk of this otherwise preventable contact sport-related neurodegenerative disease.”

In this latest study, the average rugby career length was around 18 years, with an equal number of forward and backs.

Twenty-three (74 per cent) played rugby exclusively as amateurs, with eight (26 per cent) reaching elite level, either as professional or representative internationalists.

Dr Ann McKee, director of the BU CTE Center and UNITE brain bank, and co-author of the study, said: “CTE is a preventable disease; there is an urgent need to reduce not only the number of head impacts, but the strength of those impacts, in rugby as well as the other contact sports, in order to protect and prevent CTE in these players.”

The director of the Australian Sports Brain Bank, Associate Professor Michael Buckland, points to the conclusions drawn by the Australian Senate Inquiry into Concussions and repeated head trauma in contact sports.

He said: “The findings of the recent federal government inquiry are unambiguous: there is clear evidence of a causal link between repeated head trauma and concussions and subsequent neurodegenerative disease such as CTE.

“Sports regulators need to develop and implement CTE risk minimisation protocols as a matter of urgency.”

Brain autopsies for the study were accessed from three international sites: the Understanding Neurologic Injury and Traumatic Encephalopathy Brain Bank (UNITE), Boston University School of Medicine, the Glasgow TBI Archive (GTBI), University of Glasgow and the Australian Sports Brain Bank (ASBB), Royal Prince Alfred Hospital and University of Sydney, Australia.