Former professional footballers are three and a half times more likely to die of dementia than people of the same age range in the general population, according to new research.
Experts at Glasgow University have been investigating fears that heading the ball could be linked to brain injuries.
The study began after claims that former West Brom striker Jeff Astle died because of repeated head trauma.
It compared deaths of 7,676 ex-players to 23,000 from the general population.
The sample was taken from men who played professional football in Scotland between 1900 and 1976.
The long-awaited study was commissioned by the Football Association and the Professional Footballers' Association after delays in initial research had angered Astle's family.
It began in January last year and was led by consultant neuropathologist Dr Willie Stewart, who said that "risk ranged from a five-fold increase in Alzheimer's disease, through an approximately four-fold increase in motor neurone disease, to a two-fold Parkinson's disease in former professional footballers compared to population controls".
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.
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.
"Our data show that while former footballers had higher dementia rates, they had lower rates of death due to other major diseases.
"As such, while 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."
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'This is only start of our understanding'
The link between contact sport participation and neurodegenerative disease has been subject to debate in recent years, but until this study, it was not clear whether there was any evidence of an increase in neurodegenerative disease rate in former footballers.
Former England international Astle developed dementia and died in 2002 at the age of 59. The inquest into his death found heading heavy leather footballs repeatedly had contributed to trauma to his brain.
But research by the FA and the PFA was later dropped because of what were said to be technical flaws.
Astle's family has campaigned for the football authorities to launch a comprehensive research programme.
His daughter Dawn said she was "relieved" the study eventually went ahead, and her father's case was highlighted by former England captain AlaRead More – Source
