In findings published today in The New England Journal of Medicine and funded by the Football Association (FA) and the Professional Footballers’ Association (PFA), researchers compared the causes of death of 7,676 former Scottish male professional football players who were born between 1900 and 1976 against those of more than 23,000 matched individuals from the general population.
Led by consultant neuropathologist Dr Willie Stewart, honorary clinical associate Professor at the University of Glasgow, the FIELD study found that former professional footballers had an approximately three and a half times higher rate of death due to neurodegenerative disease than expected.
Dr Stewart, said: “This is the largest study to date looking in this detail at the incidence of neurodegenerative disease in any sport, not just professional footballers.
“A strength of our study design is that we could look in detail at rates of different neurodegenerative disease subtypes.
"This analysis revealed that risk ranged from a 5-fold increase in Alzheimer’s disease, through an approximately 4 fold increase in motor neurone disease, to a 2 fold Parkinson’s disease in former professional footballers compared to population controls.”
Following the deaths of Lisbon Lions Billy McNeill and Stevie Chalmers in April, former Celtic teammate Jim Craig called for tests into a possible link between heading a football and dementia.
Although footballers had higher risk of death from neurodegenerative disease, they were less likely to die of other common diseases, such as heart disease and some cancers, including lung cancer. Reflecting these findings, the study found that deaths in former footballers were lower than expected up to age 70, and higher than expected over that age.
Dr Stewart said: “An important aspect of this work has been the ability to look across a range of health outcomes in former professional footballers. This allows us to build a more complete picture of health in this population.
“Our data show that while former footballers had higher dementia rates, they had lower rates of death due to other major diseases. As such, whilst every effort must be made to identify the factors contributing to the increased risk of neurodegenerative disease to allow this risk to be reduced, there are also wider potential health benefits of playing football to be considered.”
The association between contact sport participation and neurodegenerative disease has been subject to debate in recent years. Post-mortem studies have identified a specific dementia pathology linked to exposure to brain injury, known as chronic traumatic encephalopathy (CTE), in a high proportion of brains of former contact sports athletes, including former footballers in parallel studies led by Dr Stewart.
However, until this study, it was not clear whether there was any evidence of an increase in neurodegenerative disease rate in former footballers.
The Scottish FA said they will engage counterparts at UEFA and FIFA to establish a global response in light of the study.
Rod Petrie, Scottish FA President: “We welcome the findings of this important study – the most comprehensive one ever commissioned into neurodegenerative disease in former professional footballers anywhere in the world.
“It is important to outline that this is only the start in truly understanding the relationship. Further research is needed to determine what exactly causes the increased rates of dementia and while this will naturally involve the wider scientific community it is important that world football takes a lead on this to ensure the appropriate action to such a complex matter.”
Ian Maxwell, Scottish FA Chief Executive: “As someone who played senior football for almost 20 years I profoundly understand the importance of this research and, equally, how football responds to it.
“The game has changed immeasurably during the timeline examined by the researchers and we need to understand what exactly causes the increased rates of dementia: whether through concussion or concussion management, heading of the football, style of play, design and composition of footballs, or other factors. None the less, we must be cognisant of the findings and look where possible to reduce any risk.
“While the research is based purely on the professional game and will be discussed at the Professional Game Board, through the Non-professional Game Board we will also consider any implications for the grassroots game, notwithstanding the report states that its observationscannot be applied directly to the recreational game.
“We are also fortunate to have world-class procedures in Scotland that have been adopted across Europe but in light of these findings we must remain responsive.”
Greg Clarke, FA Chairman, said: "This is the most comprehensive study ever commissioned into neurodegenerative disease in former professional footballers. We welcome its findings and thank Dr Willie Stewart for diligently leading this important research.
“The whole game must recognise that this is only the start of our understanding and there are many questions that still need to be answered. It is important that the global football family now unites to find the answers and provide a greater understanding of this complex issue. The FA is committed to doing all it can to make that happen."
Gordon Taylor, PFA Chief Executive, said: “These findings are a matter of considerable importance to our members. We are grateful to Dr Willie Stewart and his team for their work.“The PFA co-funded FIELD, alongside The FA. It is now incumbent on football globally to come together to address this issue in a comprehensive and united manner. Research must continue to answer more specific questions about what needs to be done to identify and reduce risk factors.“Our members wellbeing is of paramount importance to us, and we are committed to representing their voice as this conversation opens up across football’s stakeholders.”