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Male footballers are 50% more likely to develop neurodegenerative disease, finds Swedish study

BMJ 2023; 380 doi: https://doi.org/10.1136/bmj.p641 (Published 17 March 2023) Cite this as: BMJ 2023;380:p641
  1. Elisabeth Mahase
  1. The BMJ

Elite male footballers were 1.5 times as likely to develop neurodegenerative disease as population controls, found a study of men who played in Sweden’s top division from 1924 to 2019.1

The observational study, published in Lancet Public Health, found that 8.9% of players (537 of 6007) and 6.2% (3485 of 56 168) in the control group were given a diagnosis of a neurodegenerative disease. The study, which used Sweden’s national health records, reported that football players had a 1.6% (95% confidence interval 1.47 to 1.78) higher risk of Alzheimer’s disease and other dementias than the controls, with 8% of footballers and 5% of controls receiving these diagnoses.

However, it found no significantly increased risk of motor neuron disease. The risk of Parkinson’s disease was lower among football players, and overall mortality was slightly lower among footballers (40%) than the control group (42%).

The research team also found that the increased risk of neurodegenerative disease was found only among outfield players, with no significant increase seen in goalkeepers, when compared with controls.

Growing body of evidence

The findings supported those reported in a previous study in Scotland that found that footballers were around 3.5 as likely to develop neurodegenerative disease.2 In a follow up, the same researchers later reported that the risk of neurodegenerative disease in former professional players varied with the position they played and length of their career but not by which decade they played in.3

Peter Ueda, assistant professor at Sweden’s Karolinska Institute and author of the latest study, said, “While the risk increase in our study is slightly smaller than in the previous study from Scotland, it confirms that elite footballers have a greater risk of neurodegenerative disease later in life.

“As there are growing calls from within the sport for greater measures to protect brain health, our study adds to the limited evidence base and can be used to guide decisions on how to manage these risks.”

The authors added that because most participants were still alive at the end of data collection the lifetime risk of developing neurodegenerative disease in both groups was likely to be higher.

Has football—and the risk—changed?

Concerning their study’s limitations, the researchers said that they could not be sure how well their findings related to today’s game. They wrote, “Most players who had neurodegenerative disease events in our study played elite football during the mid-20th century. During the past decades, football has changed in many ways which might affect the risk of neurodegenerative disease.”

Important changes have included the move from leather to synthetic balls that do not soak up water and changes to the intensity of training.

“It could be speculated that contemporary elite players, owing to more rigorous training, better equipment and, possibly, playstyles associated with less head trauma, might have a lower risk of neurodegenerative disease than did individuals who played elite football during the 20th century,” the authors suggested. “Conversely, it could also be hypothesised that the risk might be higher among contemporary football players due to their exposure to more intense and frequent games and practice from a young age.”

Commenting on the paper, Tara Spires-Jones, professor of neurodegeneration and deputy director of the Centre for Discovery Brain Sciences at the University of Edinburgh, said, “The finding that goalkeepers—who do not head the ball often—did not have increased risk, while outfield players did have increased dementia risk, adds to the large amount of scientific evidence that head injury increases risk of dementias.

“While this paper and others indicate that elite sports where head impacts occur increase risk of dementias, it is also worth noting that there is a large body of evidence that exercise in the general population decreases dementia risk. My take home message from all of the available data, including this paper, is protect your brain by both exercising and avoiding head injury or impacts.”

Virginia Newcombe, a clinical fellow at the University of Cambridge who specialises in cognitive and behavioural neuroscience, said, “The finding of a lower risk of Parkinson’s disease contrasts with previous football studies and is an important avenue for future research to understand why. It will also be important to continue to follow this cohort of players to see if the overall higher risk of neurodegenerative diseases is maintained in those who have played most recently.”

References

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