A report published this week in the Journal of Neurology, Neurosurgery and Psychiatry has looked at the incidence of neurodegenerative disease amongst former Scottish Rugby Union international players. Their findings showed a a 15-fold increase in developing MND among the rugby players and a 2-fold increase in the risk of developing any neurodegenerative disease.
The report compared 412 players with 1236 members of the general population and looked at how long they lived and what caused them to die, and then looked more specifically at the incidence of a range of neurodegenerative diseases, including dementia, Parkinson’s disease and MND.
They found no significant differences between how long the rugby players lived or their causes of death compared to the general population. But when they looked at neurodegenerative disease specifically however they did see some differences.
"There are some significant factors to consider when assessing this information," said Dr Gethin Thomas, MND Australia's Executive Research Director. "The most important factor is that this is a very small study (only ~400 players and 1200 controls). For a rare disease like MND this means the actual numbers of MND diagnoses in these groups was very small and the claimed 15-fold risk increase has very wide margins of error and may be much smaller. Larger studies are needed to confirm this outcome."
"Further, it is quite surprising that there were no cases of MND reported in the larger general population group. As MND is the most common neurodegenerative disease of mid-life, and the study included people within the ‘high risk for MND’ age range of 50-80 years old, we might have expected to see some cases recorded in this group. This may well contribute to the large risk increase seen in the study," said Dr Thomas.
"As with previous studies on exercise in MND we do not know if a particular sport or which aspect of a sport specifically (such as head trauma) might contribute to an increased risk of developing MND. A number of other factors such as genetics and differences in the metabolism of MND patients may also play key roles."
"This is the same research group that published findings of increased risk of neurodegenerative disease in professional football (soccer) players in 2019. Both studies focussed on elite players, which again means comparison to the more general population may not be valid."
"Our advice remains that there are clear overall health benefits to playing sport but care should always be taken to avoid head trauma regardless of which sport is being played. There is no evidence that playing rugby at non-elite level leads to conditions such as dementia or MND later in life," said Dr Thomas.