Footballers who repeatedly head the ball can end up suffering from dementia, new findings suggest.

A study on the brains of 14 retired footballers has for the first time found a potential link to the disease and blows to the head.

The results have promoted calls for further research as to whether dementia is more common in footballers than in the general population.

It comes after two former Norwich City players - Duncan Forbes and Martin Peters - both became victims of Alzheimer's disease.

The brains of six out of the 14 retired players involved in the research underwent post-mortem examinations.

Four were found to have chronic traumatic encephalopathy (CTE) pathology, while all six had signs of Alzheimer's disease.

CTE can cause dementia and, like Alzheimer's, is characterised by a build-up of abnormal tau protein in the brain.

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.

Professor Huw Morris of UCL Institute of Neurology said the results show more research was urgently needed in the area.

But he added that the risk for people who enjoy playing football in their spare time was likely to be low.

Mr 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.'

Dr Helen Ling, lead author of the UCL Queen Square Brain Bank study, said the research, published in the journal Acta Neuropathologica, is important but added more is needed for definitive results.

Last year, the wife of City legend Duncan Forbes welcomed research into the link between football and brain illness.

Mr Forbes, 74, made more than 300 appearances for the Canaries, and first showed signs of Alzheimer's around 2005.

In 2014, the daughter of another former Canaries star and World Cup winner, Martin Peters, spoke about her father's battle with Alzheimer's.