Retired rugby players who have suffered multiple concussions have biological differences that may make them more prone to developing motor neurone disease (MND) and other conditions, scientists have said. Researchers discovered that players who have had five or more concussions during their careers have higher levels of certain proteins in their blood that are linked to conditions including MND and Alzheimer’s disease. Scientists hope the discovery could one day lead to a “toolkit” to monitor former players.

The study comes after it emerged that former All Blacks player Norm Hewitt died aged 55 with MND. Leeds Rhinos star Rob Burrow died last month at the age of 41 after a four-and-a-half-year battle with the disease. The new research set out to examine differences in specific biomarkers between UK-based retired rugby players with a history of concussion and a group of athletes who had not suffered head trauma around seven years after they had retired from sport.

Researchers, led by academics from Durham University , looked for biomarkers in the blood linked to MND, Alzheimer’s disease and chronic traumatic encephalopathy (CTE). Information on 30 retired male athletes – including both rugby league and rugby union players – who suffered more than five concussions during their careers was compared to data on 26 retired sportsmen who had no history of concussion. All of the sportsmen were taking part in the UK Rugby Health project.

Significantly higher levels of spec.