A brain injuries expert has discovered the first confirmed case of early onset dementia caused by playing rugby.
Dr Willie Stewart said his discovery suggested international rugby would cause at least "one or two" players to develop the condition every year.
The neuropathologist examined the brain tissue of an unnamed former rugby player and a former boxer for abnormal proteins associated with head injuries and dementia.
Punch drunk syndrome
The rugby player had higher levels of the protein than the boxer who had been diagnosed with dementia pugilistica (punch drunk syndrome or PDS) Symptoms of PDS, which usually appear between 12 and 16 years after a boxer's career begins, can include memory, speech and personality problems, tremors and a lack of co-ordination.
While PDS has long been recognised as a risk for boxers, and more recently American football & ice hockey, Dr Stewart says this is the first case linking the condition to rugby.
"What we are finding now is that it is not just in boxers. We are seeing it in other sports where athletes are exposed to head injury in high levels" explained the consultant at Southern General Hospital in Glasgow.
"Those sports include American football, ice hockey and also now I have seen a case with the same pathology in somebody whose exposure was rugby."
The rugby player was aged in his 50s and had early onset dementia. He had a number of abnormal proteins in a section of his brain which was comparable to a young man who had suffered a "moderate to severe" head injury in an assault.
Dr Stewart said the percentage of rugby players affected was likely to be far lower than sports such as boxing, American football and ice hockey, where competitors are more likely to suffer repeated head trauma and concussions.
Discourage people from playing injured
He went on to urge the governing bodies of all sports with the potential for head trauma, including football, horse racing and show jumping to take responsibility to ensure athletes did not return to action too soon after suffering a concussion or other brain trauma as the NFL does in America.
"What we are really starting to worry about now is the long term problems, the things that might happen 10 or 15 or 20 years down the line," Dr Stewart said.
"The general advice for a concussion is if in doubt, sit it out. So at all levels, if you think there has been a concussion the player should be removed and not expose himself to risk.
"There is a risk that a second head injury, coming within a short space of time and before the brain has properly recovered, can be much more severe and cause more problems and more symptoms.
"Just as we discourage people from playing on with a damaged knee, even more so we would really try not to have people carry on with a damaged brain."