Conor McGregor at higher risk of dementia? MMA fighters display signs of long-term brain damage linked to the disease, study finds.     Conor McGregor, the Irish UFC star known by many as 'The Notorious', may be at risk of dementia, research suggests.

The MMA fighter, who recently, and unsuccessfully, turned his hand to boxing, has spent his career taking powerful jabs to his head.

Scientists claim these repeated blows, which have led to McGregor being worth almost $40 million (£30.4 million), cause build-ups of proteins in the brain.

Accumulations of the toxic clumps are considered a hallmark of the disease and are deemed responsible for the memory loss symptoms in old age.

The Cleveland Clinic findings, dubbed 'interesting', add to a growing body of evidence that show a link between repeated blows to the head and dementia. Despite not being confirmed, experts have previously claimed boxing to be a risk factor for the devastating disease that needs further investigation.

The new research furthers calls for more investigations to explain why jabs to the head to the head can trigger dementia.

How was the study carried out? 

For the latest study, a team of neurologists measured two biological markers of brain injury in 438 participants.

More than half of these were active professional fighters, involved in boxing or MMA somehow. The rest were retired fighters and ordinary adults. Blood samples were then taken from all of the volunteers to measure the markets, both of which were brain proteins. 

One, called tau, accumulates when the brain suffers damage. It occurs naturally with age and can be found in abundance in dementia patients.

The other, neurofilament light chain, has also been suggested as a potential blood marker of dementia.