Biomarker Indicators of Neurodegeneration in Former Rugby Players During Mid-Life

Overview

This study identifies elevated plasma phospho-tau217 and neurofilament light levels alongside reduced frontal and hippocampal brain volumes in mid-life former elite rugby players, indicating early neurodegenerative changes linked to repetitive head impacts. These biomarkers correlate with clinical features such as traumatic encephalopathy syndrome and mood symptoms, suggesting ongoing neurodegenerative processes distinct from typical Alzheimer's disease.

Background

Repetitive head impacts (RHI) and traumatic brain injuries (TBI) in contact sports like rugby are epidemiologically linked to increased risk of neurodegenerative diseases including Alzheimer's disease and chronic traumatic encephalopathy (CTE). While concussion is common in rugby, the long-term neurodegenerative consequences remain poorly characterized in living former players. Advances in fluid and imaging biomarkers now allow in vivo detection of early neurodegenerative pathology, but these have not been systematically applied to retired rugby athletes. This study aims to explore biomarker evidence of neurodegeneration in mid-life elite retired rugby players with significant head impact exposure.

Data Highlights

Key Findings

• Former elite rugby players showed significantly elevated plasma phospho-tau217 levels (17.6% higher) compared to controls, indicating possible amyloid-dependent tau pathology.
• Nearly a quarter (23.1%) of ex-players had elevated phospho-tau217 individually, and 9% had raised plasma neurofilament light, markers associated with neurodegeneration.
• Ex-players exhibited reduced frontal and cingulate cortex volumes on MRI, with longer career duration linked to lower hippocampal and white matter volumes.
• Traumatic encephalopathy syndrome was present in 12% of ex-players and was more common among those with elevated phospho-tau217.
• Raised plasma neurofilament light correlated with increased anxiety and depressive symptoms in ex-players.
• Negative correlations were found between frontal brain volume and neurofilament light (r = -0.21), and hippocampal volume and phospho-tau217 (r = -0.19), linking fluid biomarkers to structural brain changes.

Clinical Implications

These findings support the use of advanced fluid and imaging biomarkers to detect early neurodegenerative changes in former rugby players exposed to repetitive head impacts. Elevated phospho-tau217 may serve as a biomarker for amyloid-related tau pathology, while neurofilament light levels correlate with mood symptoms and brain volume loss. Clinicians should consider biomarker assessment in retired contact sport athletes to identify those at risk for neurodegenerative syndromes and guide monitoring and intervention strategies.

Conclusion

Elite rugby participation is associated with abnormal neurodegenerative biomarkers and brain volume reductions in mid-life, reflecting early pathological changes potentially linked to repetitive head impacts. State-of-the-art biomarker evaluation offers a promising approach to understanding and managing long-term neurodegenerative risks in this population.

References

1. Original Article 2024 -- Biomarker Indicators of Neurodegeneration in Former Rugby Players During Mid-Life