October 4, 2022

expert reaction to study on the risk of neurodegenerative disease in international rugby union players

A study published in the Journal of Neurology, Neurosurgery and Psychiatry looks at neurodegenerative disease risk among former international rugby union players.

This Roundup accompanied an SMC Briefing.

Prof David Sharp, neurologist and Director of the Care Research and Technology Centre within Imperial College London’s UK Dementia Research Institute, said:

“This is an important study that shows an increased risk of neurodegenerative disease is retired rugby union players. It aligns with previous work showing increased risk in other sports and also suggests that the risk may be particularly high for motor neuron disease. As the authors state, the research highlights the need to monitor the brain health of active and former sportsmen who have been exposed to repetitive head injuries. To deliver this we need new initiatives such as the Advanced Brain Health Clinic set up recently at the Institute of Sport Exercise and Health, which is assessing retired professional rugby and football players.”

Dr Neil Graham, Clinical Lecturer in Neurology, Imperial College London, said:

““This is a well-designed retrospective cohort study which significantly advances our understanding of the long-term neurological effects of rugby participation. This study shows a doubling of dementia risk in former rugby players. Rates of Parkinson’s and motor neurone disease were also significantly increased. These findings highlight the need for greater investment in dementia research, including from sports’ governing bodies, to expand programmes like ours at Imperial investigating lifelong determinants of brain health, including traumatic brain injury.  This will be key to formulating evidence-based public health advice, developing diagnostic tests for conditions such as chronic traumatic encephalopathy, and ultimately, delivering disease-specific treatments.”

Dr Brian Dickie, Director of Research Development, Motor Neurone Disease Association, said:

“This new study reports an increased incidence of neurodegenerative disease amongst former Scottish rugby union internationals. As such, it adds weight to previous reports from the FIELD team on increased risk of neurodegeneration in soccer players, albeit this new study is considerably smaller.  It therefore raises more questions than answers.

“For example, it is not clear exactly how many players were diagnosed with Motor Neurone Disease (MND), though from the information provided, that absolute number will be small. It is also surprising that there were no cases reported in the larger control group, as MND is the most common neurodegenerative disease of mid-life and the study population appears to include people in the ‘high risk’ age range of 50-80 years. Moreover, we know that the vast majority of cases of MND involve a complex mix of genetic and environmental risk factors, so the level of genetic risk may be different in high performance athletes compared with the general population.

“What is clear is that this research need to be extended into much larger populations, which will require close collaboration between researchers and rugby representative bodies across multiple countries.”

Prof Jonathan Cook, Associate Professor & Medical Statistician at the University of Oxford, said:

“This interesting study looked at a substantial number of men who played international rugby union for Scotland. The life expectancy of these men and the occurrence of neurodegenerative diseases were compared to similarly aged men also from (socioeconomically) similar areas. On the face of it the findings are worrying and the topic requires further investigation. There are a couple of uncertainties regarding the interpretation of the findings. The number of neurodegenerative diseases occurring is, thankfully, still relatively small. Related to this, the magnitude of the increased association of motor neuron disease (MND)/ amyotrophic lateral sclerosis (ALS) occurring in particular is quite uncertain and should be viewed cautiously. Additionally, only a small number of factors could be accounted for in the statistical analysis. Differences (such as lifestyle but not playing rugby as such) could explain at least in part, some of the observed findings. However, there is certainly enough to warrant more research on this topic, and consideration of the potential implications.”

Dr Virginia Newcombe, Academy of Medical Sciences / Health Foundation Clinician Scientist Fellow, University of Cambridge, said:

“This is an important study which adds to the growing evidence that repetitive head impacts in the sporting arena may lead to an increased risk of neurodegenerative disease. The authors linked rugby players listed as playing International matches with their Scottish Community Health Index (a population register in Scotland used for health care purposes). This novel approach allowed them to compare to matched controls including area socioeconomic status.  While it is likely the increased risk of dementia and Parkinson’s disease is secondary to repetitive head impacts the reason for higher risk of MND is unclear and understanding the mechanism will be important to facilitate future preventive strategies.

“It is important to mitigate the effects of repeated concussions, for further research to identify which players (and why) are at highest risk of neurogenerative disease, and to follow players in retirement to ensure those who develop problems receive the care they need. This will enable sports to continue to be enjoyed safely by all.”  

‘Neurodegenerative disease risk among former international rugby union players’ by Emma R Russell et al. was published in Journal of Neurology, Neurosurgery and Psychiatry at 23:30 UK time on Tuesday 4^th October.

DOI: 10.1136/jnnp-2022-329675

Declared interests

Prof David Sharp is funded by the UK Dementia Research Institute and has received an honorarium from the Rugby Football Union for participation in an expert concussion panel, which was used to support his research. He has also received an honorarium from the Wellcome Trust. The Advanced Brain Health Clinic Is co-funded by the Rugby Football Union, Premiership Rugby and the Football Association.

Dr Neil Graham: “I am funded by the NIHR. I am involved with research studies funded from various sources including the Ministry of Defence, RFU, PFA, and FA at present.”

Dr Brian Dickie: “No conflicts to declare.”

Dr Virginia Newcombe: “I hold a grant with ROCHE on a health economic assessment of the use of biomarkers after traumatic brain injury.”

Prof Jonathan Cook: “I am a fan of rugby union, and Scottish rugby in particular. I briefly played rugby union, badly, at school.”

For all other experts, no reply to our request for DOIs was received.