Footballers are one and a half times more likely to develop dementia than the general population, a new study suggests.
Researchers in Sweden compared the health records of 6,007 elite male football players - of which 510 were goalkeepers - with 56,168 non-footballers between 1924 and 2019.
The team, from the Karolinska Institutet and other research centres, have published their study in the respected peer-reviewed medical journal, The Lancet.
It found 9% of the footballers included were diagnosed with neurodegenerative disease, compared with 6% (3,485 out of 56,168) of the control sample.
There was no significant risk increase for footballers of contracting motor neurone disease, according to the study.
The risk of Parkinson's disease and overall mortality was also lower among football players compared to other people, the researchers found.
The academics behind the study suggested this might be "because of maintaining good physical fitness from frequently playing football".
The study also compared the risk of neurodegenerative disease among outfield players to goalkeepers. It found outfield players had a 1.4 times higher risk of neurodegenerative disease compared to goalkeepers.
Peter Ueda, assistant professor at Karolinska Institutet, said: "Goalkeepers rarely head the ball, unlike outfield players, but are exposed to similar environments and lifestyles during their football careers and perhaps also after retirement.
"It has been hypothesised that repetitive mild head trauma sustained through heading the ball is the reason football players are at increased risk, and it could be that the difference in neurodegenerative disease risk between these two types of players supports this theory."
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In recent years, there have been growing concerns about exposure to head trauma in football and whether it can lead to an increased risk of neurodegenerative disease later in life.
A previous study from Scotland suggested that footballers were 3.5 times more likely to develop neurodegenerative disease.
Following this evidence, certain footballing associations implemented measures to reduce heading in younger age groups and training settings.
Mr Ueda added: "While the risk increase in our study is slightly smaller than in the previous study from Scotland, it confirms that elite footballers have a greater risk of neurogenerative disease later in life.
"As there are growing calls from within the sport for greater measures to protect brain health, our study adds to the limited evidence base and can be used to guide decisions on how to manage these risks."
The Football Association is currently trialling banning children under the age of 12 from heading the ball in grassroots leagues and competitions in England.