Dementia will be a rare condition within 20 years, a leading Scots expert believes.

Professor Craig Ritchie said there was “every reason to be optimistic” because scientists now understand the disease and how to prevent around 40% of cases.

He said hopes remained high that a new drug that can clear harmful amyloid plaques in the brain may be able to cure dementia if it is used before symptoms have developed.

He said trials of Aducanumab had not been done at an early enough stage.

Prof Ritchie, who is Director of Brain Health Scotland, said there was strong evidence that lifestyle changes by an 85-year-old could delay the onset of dementia to 95 or even 100.

HeraldScotland:

He was speaking at the launch of the first clinic of its kind at Murrayfield Stadium, which is aiming to prevent former players developing the disease.

Research by the Lancet Commission indicated that head trauma is one of the 12 ‘modifiable risk factors’ for the disease. Others include excess alcohol intake, obesity, hearing loss in mid-life and high blood pressure.

Ex- international players, both men and women, will be closely monitored with regular brain scans and health checks in the pilot project. Former Scotland captain Gordon Bulloch is among the players to have signed up.

READ MORE: 'world first' dementia study offers prevention hopes for at risk footballers 

“I’m very very confident,” said Mr Ritchie, who is professor of the psychiatry of ageing at the University of Edinburgh.

“We understand the disease, we understand what is is going on in the brain.

“The biggest hurdle is getting services like this [brain health clinic]. We need to get to people before dementia develops.

“There are two things we can do now.  Identify risk factors and manage them as effectively as possibly - and that could be picking up diabetes or Atrial Fibrillation - and do behavioural modifications with the players and public.

“There are studies going on with disease modifying therapies.

“There is a drug [Aduhelm ] that actually clears amyloid in the brain. “However it didn’t seem to have any benefit clinically.

“The reason being that it was given too late. There is every prospect that in the future we can give that drug to people who have amyloid in their brain but no symptoms and cure the disease.”

Prof Ritchie said it was now at the point where medicine needed to move beyond research, “and put what we know into practice”.

READ MORE: Scots could be among first in world to trial new Alzheimer's drug in almost 20 years

“When you look at the list of 12 [risk factors] it’s actually plus one because the Lancet Commission didn’t include sleep.There’s good evidence around sleep and brain health.

“Some of those are just common sense such as diet and exercise. 

“But there are some which are specific [to brain health] like social isolation and stress, depression and hearing loss.

“At an individual level not smoking, not drinking and having a Mediterranean diet will have a small, incremental benefit.

“If you were destined to get dementia at 85  and you take these lifestyle changes, your onset might be 95 or 100.

He added: “We are not saying we are going to absolutely prevent someone having dementia but we are going to push that onset on by 15-20 years which means we will have a lot more healthier 80-year-olds running around Scotland.”

Studies led by Scottish consultant neuropathologist Dr Willie Stewart, established that footballers have a five-fold risk of dementia but the same research has not been replicated in rugby.

HeraldScotland:

However, Dr James Robson, Scottish Rugby’s Chief Medical Officer, who will be closely involved in the new Murrayfield clinic, says "why would we wait for the research".

He said steps were being taken to mitigate the risks for current players.

He said: “World Rugby are looking at the tackle sanction, red cards, modifying behaviour, trying to protect the brain from that point of view and putting limits on the amount of contact in a working week.” 

It is understood the the SFA has held discussions with Brain Health Scotland about replicating the clinic for footballa and potentially at Hampden Park.

"I think it’s very important for players to get involved," said Gordon Bulloch, "particularly given my experience with Tom Smith (who died earlier this month of colon cancer) who admitted to us that he had ignored symptoms and urged us all to get checked.

“Any kind of knowledge we can get about whether it is physical health or mental health is key, not just for individuals but for the whole movement.

“ You hear about others [rugby players] who maybe haven’t hit the media yet but are struggling.”

Prof Ritchie hopes the NHS will eventually run brain health clinics in every part of Scotland, giving the public access to the same health checks as  ex-footballers and rugby players.

He said: “We are being watched by the rest of the world on this.”