Scientists have established a link between early onset dementia and playing rugby.
High impact sports such as American football, ice hockey and rugby are starting to lead to the same problems experienced by boxers later in life, according to new research by neurologist Willie Stewart.
Dr Stewart's work entailed examining sections of tissue of the brain of a former rugby player. Throughout the course of his research he found a high level of abnormal proteins associated with head injuries and dementia.
The former player who took part in the study was found to have higher levels of the abnormal proteins than a retired amateur boxer who has a condition called dementia pugilistica, known as punch drunk syndrome.
Symptoms usually appear around 15 years after the boxer's career begins and problems experienced include memory, speech, personality problems and lack of coordination.
Until recently the condition was though to have only affected boxers who suffered repeated concussive injuries through blows to the head. Speaking on BBC Radio Scotland's Sport Nation programme, Dr Stewart said:
What we're find with people who've survived head injuries is that their brain shows changes down the microscope that look very much like what you would see in people with dementia, so similar abnormalities in people with Alzheimer's Disease.
Now, we've known that in boxing for instance repeatedly injuring your brain can read to a syndrome, punch drunk syndrome, and you can imagine what that is.
The pathology of that is better classified as dementia pugilistica and we kind of assumed it was only boxing related and you had to be exposed to a lot of concussive injuries. But what we're seeing here and in America is that it's happening in other sports where athletes are exposed to head injury in high levels.
Those sports include American football, ice hockey and now I've seen a case in a person whose exposure was rugby.
Dr Stewart, who is based at the Southern General Hospital in Glasgow, believes better precautions should be taken by players and organisers.
If we say it's 1% of people playing at international rugby level, then in any Six Nations weekend that's one or two players who could go on to develop a dementia they wouldn't otherwise have been exposed to.