England rugby legend and World Cup winner Lewis Moody this week shocked fans after revealing he had been diagnosed with motor neurone disease (MND) at just 47. 

Discussing his diagnosis, he said: 'You're given the this diagnosis of MND and we're rightly quite emotional about it, but it's so strange because I feel like nothing's wrong.

'I'm still capable of doing everything and anything. And hopefully that will continue for as long as possible.' 

His diagnosis has, however, raised further questions about the potential role of certain sports in the development of the disease.

Fellow union player and Scottish international Doddie Weir died from the condition in November 2022, as did England rugby league star Rob Burrow in June 2024. 

MND is a rare neurological condition that damages the nervous system over time, resulting in difficulties walking, speaking and breathing as the condition progresses. 

It's not fully understood why it occurs and there are no effective treatments to halt its cruel march — around 5,000 adults in the UK have MND and there is a one in 300 risk of developing the condition over the course of a person's life.

While specific genes are known to play a role in up to one in ten cases, experts also believe lifestyle and environmental factors may increasingly raise the risk. 

Traumatic Head Injuries  

As things stand, experts cannot say for certain that regularly playing rugby — or any other sport — as a professional or at an amateur level causes MND.

But it may seem from the headlines that there is an obvious heightened risk.

Some studies also suggest professional footballers may also be more likely to develop MND — up to six times more likely according to some research — than the general population. 

But others have found no such association. 

These mixed results are likely due to the fact that these are small studies involving too few participants to produce robust findings. 

Last year, however, Durham University researchers found multiple concussions in retired rugby players made them more prone to developing MND.

The team who looked at 30 retired players with a history of concussions found they caused changes proteins in their blood that make them more prone to the illness.

Their blood samples showed more signs of neural damage than compared to a control group of 26 athletes who had not suffered head traumas.

Researchers in the UK and Italy are also currently undertaking the largest study of its kind to date, assessing data on MND rates among thousands of professional footballers over decades. 

Lewis Moody, himself, has also long campaigned for mandatory time limits on contact in training and for more money to be made available for the care of players once their careers have concluded. 

Intense physical activity 

Equally, some scientists have suggested intense physical activity may raise the risk of developing MND. 

Limited research has hypothesised that as extreme athletes, professional sports men and women generate such intense levels of body heat that it can somehow damage the nerves that control movement.

Meanwhile, a separate 2021 study by the University of Sheffield found high intensity exercise increases risk of MND in people with certain genetics.

The scientists found individuals who have a mutation in the C9ORF72 gene have an earlier onset of MND, if they regularly do highly intense physical exercise.

Professor Dame Pamela Shaw, a neurologist at Sheffield University and study co-author, said: 'Clearly most people who undertake strenuous exercise do not develop motor neurone injury.

'And more work is needed to pin-point the precise genetic risk factors involved.'

Agricultural chemicals and heavy metals  

Another possibility is exposure to pesticides.

One 2022 study by researchers in New Zealand published in the journal Occupational and Environmental Medicine found that people exposed to several pesticides and were up to 70 per cent more likely to develop MND. 

These pesticides included insecticides which kill insects, fungicides that kill fungi and fumigants—which are vapourised deterrents.

But they also discovered exposure to petrol and diesel fumes also raised the risk and concluded further research was vital to prove any such link. 

Similarly, heavy metals like lead and mercury have been linked to a higher risk of amyotrophic lateral sclerosis (ALS), the most common form of motor neurone disease.

ALS claimed the life of Sandra Bullock's partner Bryan Randall in 2023 and the acclaimed scientist Stephen Hawking famously suffered from it.

Smoking  

Several studies have linked smoking to a higher risk of developing ALS, and other worrying health problems.

One 2011 study that looked at 832 participants with ALS found that for every extra 10 cigarettes per day, the risk of developing ALS rose by 10 per cent.  

However, a 2020 King's College London study found in their study there wasn't a strong enough correlation to link two.

The habit also raises the risk of many cancers, heart disease, stroke, type 2 diabetes and chronic obstructive pulmonary disease (COPD).

Military service   

Equally, another career choice may increase the risk of developing the condition, studies suggest.

Research published in 2015 in the journal Occupational & Environmental Medicine, found military veterans had a 49 per cent higher risk of being diagnosed with MND.

The scientists, who tracked 57 000 veterans, however acknowledged: 'We could not rule out that smoking — and perhaps other lifestyle factors — may be responsible.

'Trauma may play a role in the increased risk but further studies are needed.'