Motor Neurone Disease in Professional Sportspeople: The IIAC Publishes an Information Note Following Its Recent Review

On Thursday 9^th October, the Industrial Injuries Advisory Council (IIAC) published an information note concerning motor neurone disease in professional sportspeople. 

The rise in neurodegenerative illnesses among high-profile sportspeople over the last decade has drawn increased attention. This blog has previously covered civil claims by professional athletes, while many sporting authorities have implemented rules and protocols to reduce associated risks. 

The IIAC reviewed the evidence concerning the risk of neurodegenerative diseases (an umbrella term encompassing several diseases) in professional sportspeople, having previously considered this issue in May 2016.

The conclusion of the review was that:

“The IIAC takes the view that the current evidence base, while stronger than the last time Council reviewed this information and published in May 2016, is not sufficiently clear nor consistent enough to allow prescription for MND in professional sportspeople.”

The Outcome of the Review

MND is a fatal neurodegenerative disease with largely unknown causes. It causes rapidly progressive paralysis, leading to death within three to five years of symptom onset. In England, the annual incidence is about 2 per 100,000 people and is slightly higher in men. Incidence rises rapidly after age 40 and peaks at ages 70 to 74 (Opie-Martin et al, 2021).

To recommend prescription an exposure-related risk in a particular group of paid employees should be at least twice that of non-exposed individuals. The recommendation should also be unlikely to be overturned by future research. This threshold was not met in the current empirical studies considered in the note, with the evidence not being “sufficiently clear and consistent”.

Notably, studies suggested an association between MND and head injury (Watanabe and Watanabe 2017) but no clear direct mechanistic pathway between the two. The evidence was particularly supportive concerning sub-concussive head impacts, which are likely to occur in a number of contact sports.

There were also potential associations suggested between physical activity and MND and also studies suggesting an association with genetic susceptibilities (Julian et al, 2021).

The Studies

The IIAC considered studies of American football players, soccer players from various countries, a single study of elite rugby players, and several studies of other professional sportspeople. Where there were overlapping populations between studies, only the largest and most recent studies were included. This meant that only one American football study was considered, and a single rugby study focussed on 654 former Scottish international rugby players (Russell et al, 2022)

Potential limitations of the studies included the identification of relevant study populations, the identification of those with MND, the reliability of diagnoses, the selection of appropriate reference populations, and the linkage of the study population to disease registers and death certification.

The Future

The IIAC is aware that further studies are underway or are planned and are likely to provide additional information about the relationship between professional sport and motor neurone disease. Also, the IIAC has commissioned the University of Manchester to review literature on cognitive impairment and Parkinson’s disease, which might provide additional relevant information. The IIAC will revisit the topic when sufficient further information becomes available. This is anticipated to be in mid-2026.

The full information note, which includes details of all the studies considered, is here.