Thirty former professionals have signed up to a study into the early signs of dementia amid concerns for modern footballers' health.
Previous research has shown that ex-professionals are three and a half times more likely to die of dementia than the general population.
Five of England's 1966 World Cup-winning squad have been diagnosed with the disease.
But the neurosurgeon who led research into football's links with dementia has warned the issue is "not just for older-era footballers but modern-era footballers as well".
Dr Willie Stewart, of Glasgow University, also said lighter modern footballs "could make the problem even worse" because of the speed they travel before striking a player's head.
Former Premier League players and internationals are among the 30 who have joined a study, led by Dr Michael Grey at University of East Anglia, which has started gathering results.
They include former Wales and Norwich City forward Iwan Roberts, who retired in 2005. He told BBC Sport: "I'm 52 now and I'm a firm believer in prevention being better than cure, so I would rather know that by taking these tests - if something wasn't right - I could put things into place or plan for the future.
"The modern player now should be concerned. The balls are lighter, but by being lighter they travel through the air quicker and reach your head far quicker."
The study will add 30 former professional footballers to 40 amateurs over the age of 40, and compare them with a 60-strong group who have not played football.
Grey, who wants more former professionals to come forward, said interest so far had come from those who wanted to "help the science" and those "interested in their own brain health".
Their concerns chime with those of Dawn Astle - the daughter of former West Brom striker Jeff Astle, who died of because of a brain condition associated with heading footballs.
She says she has been contacted by families of people who played in the 1970s and 1980s.
In addition to the death of World Cup winner Nobby Stiles, who had dementia, last week and Sir Bobby Charlton's diagnosis with the same condition, Stewart referenced the recent passing of 36-year-old former Hearts and Rangers defender Marius Zaliukas, who had motor neurone disease (MND).
Stewart's research, which was commissioned by the Football Association (FA) and the Professional Footballers' Association (PFA), also found that former footballers were four times more likely to die of MND.
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Calls for more research
Following Stewart's findings, changes have been made to how heading is taught in youth football in England, Scotland and Northern Ireland.
But Stewart is critical of how football has responded to his research, published in October 2019. Roberts also says that more support could be offered to studies such as the one he is involved in.
"Credit to the FA and Scottish FA - they took that data and have tried to make adjustments to improve the game and reduce the risk," said Stewart. "But there has been silence from [world governing body] Fifa and [European governing body] Uefa and from other football associations.
"This is a global game - 250 million people play football regularly, Fifa tells us. Where is the global response to this?
"I thought [the research] would be enough for football to wrap its arms around the game and deal with this seriously - to say: 'This is something we need to put more effort into, with more research and mitigate against future problems.' And none of that has happened."
A Fifa spokesperson said it takes brain injuries in football "very seriously", adding: "Protecting the health of players is - and will remain - a top priority in developing the game."
It also says it has driven the introduction of an "additional permanent substitution" for concussions, with a trial due as soon as is permitted. It also continues to evaluate research on concussions and brain injuries.
Uefa said it has introduced updated heading guidelines based on independent research and is running a concussion awareness campaign.
Roberts added: "It's not like people want to someone to blame, that's not why I got involved with the study. But when you see so many players with dementia - and it's not just the players, it's their families as well that have to go through the sadness - I feel the FA and PFA could do a lot more, especially with so much money in the game nowadays."
Asked if he would be worried if he was a Premier League player, Stewart added: "I certainly would.
"The sideline treatment of head injuries in football is woefully inadequate and if you can compare it to rugby it's dreadful, from a bygone era. The exposure to head injuries and impacts has not changed, it's not cutting back from heading in training, for instance.
"The only way we will know whether something has changed is to wait until current Premier League footballers are in their 60s and 70s, but by then it's too late.
"I don't want to come back in 40 years' time, if I'm still around, and do the research and find nothing has changed and dementia risk is just as high in modern footballers."
The FA said it had made an "ongoing commitment to explore and invest in further research" and added that its next project would investigate the causes of increased death from brain diseases, highlighted by Stewart's study. It is also supporting to further studies into the early signs of brain injuries in former footballers.
The PFA is supporting two studies, one on head injuries in sport and one with the Drake Foundation, where 300 former players are being recruited to help research into links between heading the ball and concussion or long-term cognitive function.
The union also says it is part of the working group on concussion substitutions and is supporting players with dementia and general care, including members of the 1966 England team.
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