A study finds 31 former rugby league players have been diagnosed with the degenerative brain disease chronic traumatic encephalopathy (CTE).

In short:

Of 51 brains of former rugby league players examined, 31 were found to have CTE.

The disease was found in players in their 20s, 30s and 40s, from amateur to professional levels.

The findings were presented at the International Sports Concussion Conference in Melbourne on Tuesday.