The simple answer is we do not know yet. There is not enough evidence to show there is a strong link. We know a combination of environmental and lifestyle factors act together with specific genes to predispose people to developing MND. However, as yet we don’t know exactly how these factors trigger the onset of disease. We therefore cannot say that one factor, or one sport, is causing the trigger for this disease.
The lifetime risk of developing motor neurone disease (MND) is around 1 in 300. The exact cause of the disease remains unknown and funding for research to understand this and ultimately develop treatments is much needed.
The MND Association is committed to the care of people living with and affected by MND and, through our research funding, to a world free of MND. Here, we explore evidence that suggests a link between sport and MND.
Research findings: MND and sport
A small number of studies have tried to determine if exercise or head impact from contact sports have caused increased risk of neurological diseases such as Alzheimer’s disease, MND and chronic traumatic encephalopathy (CTE). In the past decade, some evidence has emerged suggesting a potential link between contact sport participation, including football and American Football (NFL), and an increased risk of neurodegenerative disease.
New research suggests there might be a link between extreme exercise and MND in males, but not females. Researchers from the University of Sheffield have previously published work which suggested that there was a link between extreme exercise (more than 6 hours of strenuous exercise or more than 12 hours of any leisure-time exercise per week) and the risk of developing MND. Researchers have now investigated this further, looking at males and females separately, to look at the biology behind this link further. They looked at exercise data and genetic data from healthy people and people with MND. They found a link between extreme exercise and MND in men, with data suggesting men who exercise to an extreme amount have an increased risk of developing MND and develop MND at an earlier age.
Researchers looked for a biological basis for this link, and their study results suggested it could be related to mTOR signalling, an important pathway in cell health and survival. Activation of this pathway is thought to be protective. Extreme exercise in males was found to be linked to gene changes which mean this pathway may not work correctly, so this protection may not be possible. More research is needed to look further into how and why extreme exercise might increase the risk of developing MND in men. Researchers are clear that these results apply to frequent, strenuous exercise, and should not prevent people from exercising in general.
Other findings from studies have suggested people who play football at a professional level have an increased risk of neurodegenerative disease, with a few of these studies suggesting that being a professional footballer increases a person’s risk of developing MND (Chio et al 2005: Chio et al 2009). Another study (Russell et al 2022) concluded that former Scottish international rugby union players had an increased risk of developing MND compared to the general population.
There are also a small number of research findings which suggest that an increased susceptibility to MND is associated with some professional sports, and sports prone to repetitive concussive head and cervical spinal trauma (Blecher et al 2019).
However, the research is not definitive and as yet there's no proven link. It is clear a lot more research is needed.
We recognise this and are working with researchers and institutions to progress research in this area.
Correlation or causation?
While studies carried out to date suggest a correlation between these professional sports and MND they do not demonstrate causation – so they recognise that professional footballers and rugby players are more likely to develop MND but they don’t suggest that playing football professionally, or any particular aspect of doing that, directly leads to a person developing MND.
It is also important to keep in mind the number of reported MND cases in these studies is still relatively low, and so concluding there is a definite increased risk could be misinterpreted if this is simply a cluster due to random chance.
This research is of great interest to us at the MND Association, and public attention regarding the risk of contact sports and neurodegenerative disease is increasing.
Taking action
We continue to fund research which we hope will lead to answers. We are investing time and money to research the link between sport and MND. We are making progress, and will continue to fund research until we have uncovered the cause and identified effective treatments.
While there is a growing movement within sport to understand, recognise and, where necessary, mitigate against negative long-term effects, it is also clear a lot more research is needed. We recognise this and are working with researchers and institutions to facilitate MND research.
We have collaborated with charities MND Scotland and My Name’5 Doddie Foundation to fund new research looking into whether traumatic brain injuries can lead to an increase in the risk of developing MND. The study, traumatic brain injury and motor neurone disease (T-MND), is led by Professor William Stewart and his team at the University of Glasgow.
Following some earlier research about increased risk and early onset of MND in professional football players from Italian Soccer Teams we, along with My Name'5 Doddie Foundation and the Darby Rimmer MND Foundation, are also providing support towards an 18 month research project investigating a potential link between playing professional football and developing MND. The project will analyse death certificates from thousands of footballers in the UK and Italy to discover whether they had a higher risk of dying from MND than the general public. Professor Ammar Al-Chalabi of King’s College London and Dr Elisabetta Pupillo of the Mario Negri Institute for Pharmacological Research in Milan, Italy are leading the study.
We are jointly with My Name’5 Doddie and the University of Liverpool supporting research led by Dr Caroline Staunton examining whether repeat physical traumas could contribute to the development of MND, taking an insight from professional rugby. This research aims to answer questions on our understanding of repeated physical trauma experienced by people who play rugby and other contact sports and its possible links to MND with the potential of developing a novel therapy in the future.
We are also part of an MND and Sport Expert Working Group, which works to explore the potential link between sport and MND. The group includes representatives from the MND Association, MND Scotland and My Name’5 Doddie as well as people living with MND, and is in response to a number of scientific publications which indicate there may be an increased risk of developing MND among people who participate in elite-level sport, including football and rugby. The group includes experts in sport and MND from around the world. It will seek to better understand the possible link, determine what research questions need to be asked in order to identify any underlying causes, as well as determine what resources are available, or required, to answer them.
It is one of our frustrations as an Association that we haven’t yet pinpointed all of the causes of MND. We continue to fund research which we hope will lead to answers. A combination of environmental and lifestyle factors likely act together with specific genes to predispose people to get MND. What we don’t know is the exact recipe of these factors that triggers onset of the disease.
Of course this kind of research costs money and we need the funds to ensure this vital work continues. It is only through support from our community to continue our vital research will we find the answers.
Related articles
Our MND Research Blog takes a deep dive into topical MND research studies and helps explain the science.
Is there a link between rugby and MND?
In October 2022, a paper was published was published which investigated the risk of developing a neurodegenerative disease, such as MND, among former Scottish international rugby players. The paper concluded that former Scottish international rugby union players had an increased risk of developing MND compared to the general population. In this blog, we sat down with Dr Brian Dickie, Director of Research Development at the MND Association to discuss whether there is a link between playing rugby and MND - in the article we discuss the paper and what this latest research means to people who play or have played rugby.
Physical exercise as a risk factor for MND – is it in our genes?
The question of whether exercise causes, or contributes towards MND is still very much unanswered.
A study by Julian and colleagues (2021) attempted to provide answers to the question of whether exercise contributes, or causes MND. The study used huge data sets of genetic information, bioinformatics and validated questionnaires for physical exercise in specific genotypes to shed more light on a potential association between exercise and MND, in a way that is claimed to remove much of the potential issues with bias reporting. We wrote a piece on physical exercise as a risk factor for MND if you'd like to read more.