Two new studies have found no cases of early-onset dementia in 200 former professional rugby players, but revealed biological and structural brain changes linked to increased long-term risk.
The research involved retired male and female players aged 30 to 61, and identified raised levels of biomarkers associated with neurodegeneration, despite no clinical diagnoses of dementia.
Blood tests showed some former players had higher levels of p-tau217 — a form of tau protein that, when abnormal, is linked to brain cell damage.
Tau usually supports nerve cells in the brain, but following injury it can form tangles that, along with amyloid plaques, are associated with Alzheimer’s disease and chronic traumatic encephalopathy (CTE) — a condition that may lead to dementia years after repeated head impacts.
Professor David Sharp is director of the UK Dementia Research Institute Centre for Care Research & Technology at Imperial College London.
He said: “We didn’t see any cases of early dementia in this group of former players, which is reassuring.
“However, the changes in blood biomarkers and brain imaging abnormalities show some long-term effects of repeated head impacts on the brain.
“We would not usually expect signs of dementia in mid-life, but we need to follow-up our cohort to clarify whether our biomarker results indicate that some retired players have early neurodegeneration that might lead to later dementia.”
Researchers from Imperial College London, University College London (via the Institute of Sport, Exercise and Health), and the UK Dementia Research Institute found p-tau217 levels were on average 17.6 per cent higher in former players compared with 33 control participants who had no history of significant head impact.
A subgroup of 46 players (23 per cent) had levels considered significantly raised, though still below those typically seen in patients with Alzheimer’s.
MRI scans also showed reduced brain volume in some former players, particularly in the frontal lobes — which help regulate behaviour and thinking — and in the hippocampus, which is essential for memory. Greater reductions were seen in players with longer careers, even when age was accounted for.
Cognitive tests did not show significant differences between the two groups, but former players reported more symptoms including depression, anxiety, pain, behavioural changes and sleep disturbance. Many of these symptoms had other possible explanations, such as treatable mental health conditions.
The findings are based on baseline assessments at the start of a four-year study which will follow participants to monitor changes in brain health.
Dr Richard Sylvester, co-lead of the study from the Institute of Sport Exercise and Health at University College London, said: “These findings suggest that neurological symptoms in former rugby players in mid-life may not all be due to head injuries sustained participating in sport and even cognitive and behavioural changes in this group are not commonly a sign of dementia.
“We would encourage any former players with concerns about their brain health to seek expert clinical assessment as there may be treatable issues that could significantly improve their quality of life and help to reduce the risk of developing dementia in later life.”
