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Traumatic brain injury-related neurodegeneration among ex-professional footballers and rugby players

By 13 November 2020No Comments
BC Legal
Published: September 2019


This report examines the link between professional football/rugby and degenerative brain damage based upon research conducted by Dr Willie Stewart, the first clinician to diagnose chronic traumatic encephalopathy (CTE) in an ex-professional footballer back in 2014. CTE is a progressive brain condition that is thought to be caused by repeated blows to the head and repeated episodes of concussion. Dr Stewart leads an ongoing FIELD study, commissioned in 2017 by the British Football Association (FA) and the Professional Footballers’ Association (PFA). The aim of the research is to contribute to a broader understanding of dementia in former football and rugby players. Research led by British Professor of Neurology, David Sharp, contributes to the discussion by investigating the effects of single head trauma on progressive brain deterioration and long-term cognitive decline.


The FIELD project was designed as a retrospective cohort study, with over 10,000 former professional footballers and 30,000 members of the general population participating. The project is ongoing, and results are expected by the end of 2020. A previous study involving Dr Stewart inspected 11 brains (7 from ex-footballers, and 4 from ex-rugby players) for evidence of CTE pathology. In a different study led by Professor Sharp, 21 patients were recruited who had suffered a severe head injury between 18 and 51 years ago, either in a car accident, assault, or fall. Their brains underwent PET scans and were compared against the scans of 11 healthy individuals. The scans were testing for ‘tau tangles’, clumps of tau protein in the brain which are linked to cell damage and connected to CTE.

Key Findings

Dr Stewart’s study identified that 72% of former footballers and 75% of former rugby players, with a history of dementia, exhibited CTE pathology. The majority of the 7 ex-footballer and 4 ex-rugby players examined first showed symptoms of dementia in their 50’s or 60’s. Incidence of CTE pathology was 6-times higher among ex-professional athletes compared to the general population. However, whilst CTE is prevalent in a high number of the patients studied, in many cases it is not the primary pathology driving dementia. A number of other pathologies, including Alzheimer’s, Parkinson’s disease and chronic cerebrovascular disease were found to co-exist with CTE. Mixed pathologies are typically observed in very elderly people but are more likely to be found among younger patients when they are former athletes. Professor Sharp’s study reveals that, whilst none of the control group brains contained ‘tau tangles’, 15 of the 21 head injury victims has unusually high levels of tau and nerve damage. This is the first time that tau tangles have been observed in living patients.


The report centres on a high profile and topical issue which is currently receiving a large amount of attention from the media and former athletes. The research conducted by both Dr Stewart and Professor Sharp highlights the complexity of dementia and the existing gap in understanding in the relationship with former athletes. It certainly shows that CTE is not the only type of brain damage associated with sport-related head trauma and is part of a spectrum of degenerative brain diseases. It is important not to take these findings as an argument against playing sport altogether, but instead focus on what can be done to reduce risk around head injuries and protect players. Greater understanding of sport-related brain damage is necessary for protecting players both in professional and community sport.