Former professional footballers are three and a half times more likely to suffer from dementia and other serious neurological diseases, a landmark study has found, confirming a long-suspected link between the sport and brain damage.

A 22-month research project by the University of Glasgow’s Brain Injury Group also discovered there was a five-fold increase in the risk of Alzheimer’s, a four-fold increase in motor neurone disease and a two-fold increase in Parkinson’s.

Ryan Giggs and Daniel James under fire over actions after head collision Read more

The report was unable to establish whether the cause of the higher levels of brain disease was due to repeated concussions, heading leather footballs, or some other factor. However, the Football Association, which helped fund the research, said it would be setting up a task force to examine the potential causes more deeply.

The family of the former West Bromwich Albion striker Jeff Astle, who died in 2002 of what a coroner said was an “industrial disease” partly caused by heading heavy footballs during his career, said they were shocked at the scale of the problem.

“My overall feeling is that I am staggered even though my own research and instinct was always that there was a serious problem,” said his daughter Dawn Astle, who has been contacted by more than 400 families of former players with dementia.

“There will be no celebrations. We knew dad could not be the only one. We just wanted that question answered. We just wanted to see that football cared enough to find out the scale of the problem, to do the right thing and be there for these people when they need them most. Whatever they do next, it must be across all parts of the game. And these players who have suffered dementia must not be a statistic – they must never be forgotten.”

The FA confirmed that despite the study, which used recently digitised NHS Scotland data to compare the causes of death of 7,676 former male professional players who were born between 1900 and 1976 against those of more than 23,000 people from the general population, there was not yet enough evidence to change any aspect of the game.

“Our research shows the number of aerial challenges has already been reduced significantly over the years as we have changed to smaller pitches and possession-based football,” the FA chief executive, Marc Bullingham, said. “However, as new evidence comes to light, we will continue to monitor and reassess all aspects of the game.”

Data from Opta backs up Bullingham’s assessment, with high crosses in the Premier League having declined from a peak – since Opta records began in 2006 – of 38.2 per game in 2008‑09 to a low of 24.2 last season. However, the research is still bound to increase the pressure on the International Football Association board, which meets in Zurich on Wednesday, to consider implementing rules that allow “concussion substitutes” if a player gets assessed for a head injury during a match.

Many doctors and former players have been critical of the slow response of the Professional Footballers’ Association to the dementia problem over the past decade, with Chris Sutton, whose father Mike – also a former Norwich player – suffered from dementia, calling for an apology.

“If Gordon Taylor had anything about him he would apologise to all his union members and their families who he has failed … his own members dying in the most horrible and humiliating way … he failed my dad and hundreds more,” he said on Twitter. However, the PFA’s deputy chief executive, Bobby Barnes, said the organisation now better understands the scale of the problem. He added that five members of the PFA had also agreed to donate their brains to medical science after they die.

The Glasgow University study also found former footballers were less likely to die of other common problems, such as heart disease and some cancers, and lived on average three and a quarter years longer.

Former UC Berkeley cheerleader says coaches ignored concussions in lawsuit Read more

Dr Carol Routledge, the director of research of Alzheimer’s UK, said the benefits of playing football outweigh the disadvantages.

“Dementia is caused by complex brain diseases and our risk is influenced by our genes, lifestyle and health,” she added. “The best evidence suggests that good heart health is the best way to keep the brain healthy, so when played safely, a kickaround with friends is still a great way to stay mentally and physically active.”