A POTENTIAL cause of dementia thought to arise from blows to the head has been confirmed in a group of retired footballers for the first time,.

The findings, from a study of 14 former players, suggest a possible link between playing football and developing such conditions later in life, researchers said.

The results provide a platform for a "pressing research question" on whether dementia is more common in footballers than the general population, Dr Helen Ling, lead author of the UCL Queen Square Brain Bank study said.

The results show more research is urgently needed to assess risks faced by players and allow measures to be put in place to protect footballers from long-term damage, Professor Huw Morris of UCL Institute of Neurology said.

Prof Morris said: "We do not yet know exactly what causes CTE in footballers or how significant the risk is.

"Major head injuries in football are more commonly caused by player collisions rather than heading the ball.

"The average footballer heads the ball thousands of times throughout their career, but this seldom causes noticeable neurological symptoms."

He added: "Of course, any kind of physical activity will be associated with health risks and benefits and it is well-established that playing sports can significantly improve physical and mental health."

The players involved in the study, 12 of whom who had attended the same Swansea clinic between 1980 and 2010, eventually died of advanced dementia, all began playing football and heading the ball when they were children or teenagers and continued for an average of 26 years.

Consultant psychiatrist Dr Don Williams, who ran the study in Swansea, said he was motivated to do so after being approached by a man whose footballer father had been diagnosed with dementia, and who wanted to know if headers could be the cause.

He said: "As a result I looked out for men with dementia and a significant history of playing soccer, followed them up and where possible arranged for post-mortem studies to be carried out.

"The results suggest that heading the ball over many years, a form of repetitive sub-concussive head injury, can result in the development of CTE and dementia."

Dr Ling said: "The most pressing research question is therefore to find out if dementia is more common in footballers than in the normal population."

She said that chronic traumatic encephalopathy (CTE) can cause dementia and, like Alzheimer's disease, is characterised by a build-up of abnormal tau protein in the brain.

The rate of CTE detected in the brains of the players was greater than the 12 per cent average found in a previous study which looked at brains from the general population.

Dr Magdalena Ietswaart, a cognitive neuroscientist from the University of Stirling and author of the 2016 study which showed heading causes instant, short-term changes to the brain, said: “While we need to protect footballers who will be experiencing small, but significant short-terms changes to their brain chemistry after they head a football, we need to be able to pinpoint what stage this may be having the biggest impact and uncover at any age the mechanisms that relate to brain health in the long-term, before we can make any concrete decisions about the game among young players.”

In 1998 former Celtic player Billy McPhail lost his legal case for disablement benefit over a claim that he developed the first stages of senile dementia as a result of heading the old- fashioned footballs. He died in 2003.

An inquest into the death of former West Bromwich Albion striker Jeff Astle ruled he died aged 59 from a degenerative brain disease caused by the same actions in 2002.

In 2014 former Dundee United full-back Frank Kopel died aged 65 after suffering from vascular dementia since 2009.