- Video report by ITV News Correspondent Sejal Karia
Former professional footballers are around three and a half times more likely to die from neurodegenerative disease than the general population, according to a new study.
Research from Glasgow University revealed the "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."
The report assessed the medical records of 7,676 men who played professional football in Scotland between 1900 and 1976.
Three of England's victorious World Cup team from 1966 were later diagnosed with neurodegenerative diseases; Nobby Stiles Martin Peters and Ray Wilson were all treated for the condition, while Jack Charlton admits to memory loss.
Their records were matched against more than 23,000 individuals from the general population, with the study led by consultant neuropathologist Dr Willie Stewart and commissioned by the Football Association and the Professional Footballers' Association.
- Dawn Astle, daughter of former England striker Jeff, discussing the report
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.
The study - titled "Football's Influence on Lifelong Health and Dementia Risk" or FIELD for short - found that deaths in ex-footballers were lower than expected up to age 70, and higher than expected over that age.
Dr Stewart said in a statement: "An important aspect of this work has been the ability to look across a range of health outcomes in form
"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 former England and West Bromwich Albion striker Jeff Astle developed dementia and died in 2002 at the age of 59. The inquest into his death found heading footballs during his professional career had caused repeated head trauma.
His daughter, Dawn Astle, who along with her mother Laraine has campaigned on this issue for many years, told ITV News the issue of dementia in footballers had been "swept under the carpet" despite the coroner's ruling into her father's death nearly two decades ago.
Ms Astle said: "It's coming up to 18 years since my dad died at the age of 59 and back in November 2002 a corner was very clear in saying that the repeated heading of footballs during his playing career had contributed to his death and the result of the coroners court hearing was industrial disease, so in other words dad's job had killed him."
In light of the study, Ms Astle hopes there will a change across the game, including at grassroots level.
"There's no evidence to say it's a generational problem there's no evidence to say it's because of the old leather ball," she said.
"I think that what's really important to say is that these players must not remain as a statistic, their deaths should stay on the conscious of the game forever."
FA chairman Greg Clarke said: "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."
PFA chief executive Gordon Taylor said it was "incumbent on football globally to come together to address this issue in a comprehensive and united manner".
He added: "Research must continue to answer more specific questions about what needs to be done to identify and reduce risk factors."
The FA said in a statement: “The study does not determine whether the cause is due to concussions suffered by the group of professional footballers, or concussion management, or heading of the football, or style of play, or the design and composition of footballs over the years, or personal lifestyle, or some other factor.”
The governing body said the study’s findings had been reviewed by an independent Medical and Football Advisory Group, which recommended re-issuing the current FA concussion guidelines and best-practice advice for coaching heading and called for further steps to improve head injury management, like supporting UEFA’s proposals to introduce concussion substitutes.
The group said more research was needed and there was “not enough evidence at this stage to make other changes to the way the modern-day game is played”.
The FA said it was not important to try and establish “whether or not the results from this historic group of former professional footballers relates, in any way, to the modern-day professional footballer”.
It said it had written to Fifa and Uefa to offer its full support on future research in this area as well as share the findings of the study with them.