Experts say more research must be carried out into the dangers of heading a football after a study suggested it could lead to professional players developing dementia later in life.

Iwan Roberts, who played as a striker for the Canaries between 1997-2004, said he couldn't help but wonder if it he was at risk of being affected by the heading during his career - but added all sport contained some form of risk.

His comments came after a study suggested a link between footballers who repeatedly headed footballs and later developed signs of dementia.

Researchers found the brains of four of 14 retired players, which were examined post-mortem, contained chronic traumatic encephalopathy (CTE) pathology - while a further two had signs of Alzheimer's disease in addition.

The rate of CTE detected in the footballers' brains was greater than the 12pc average found in a previous study which looked at 268 brains from the general population.

'Heading was a big part of my game,' Mr Roberts said.

'I'm a little bit forgetful and sometimes struggle with people's names, but I don't think I'm the only one with that problem.

'But you just can't know if it's something which could start creeping in.'

Mr Roberts said he was in favour of banning children aged under ten from heading the ball.

'I don't think it's necessary for young children to be heading the ball, there is plenty of time in their teens when they can master the art,' he said.

Professor Michael Hornberger, professor of dementia research at Norwich Medical School, University of East Anglia, said it was an 'interesting' study which needs to be followed up with research looking at much greater numbers of people.

'The brain is in a bubble in your skull and it bounces around a little when the footballer heads the ball,' he said.

'This creates an inflammation. Too much of this can accelerate dementia.'

He said bigger studies in USA have examined the link between american football and dementia, which has resulted in guidance being issued by the sport's governing body.

The study's researcher Professor Huw Morris said it was not yet known what exactly causes CTE in footballers, or how significant the risk is.