RUGBY players are twice as likely to get dementia because they take so many blows to the head, يقول الباحثون.
Ex-internationals lived longer than average but rates of the condition were 2.2 times higher than in non-players.
Forwards and backs were affected equally.
مرض الشلل الرعاش is three times more common while motor neurone disease, although rare, هو 15 times as common.
The findings are from a غلاسكو University study comparing 412 former Scottish players with 1,236 non-players.
There is growing evidence that lots of smaller bumps can have devastating effects years later.
Professor Willie Stewart said: “We’re finding over and over again that head injury and head impact exposure in sport increases your risk of neurodegenerative disease.
“It’s a risk that we need to do something about.
“The modern game has just seen the head impact risk go up and up, as far as I’m concerned.
“Precautions should be adopted. I wouldn’t stop children playing but I would ask the coach about injuries.
“If they don’t understand, go to the next club.”