A ground-breaking study has found Aboriginal Australians are three times more likely to suffer dementia than non-Indigenous Australians.

Researchers say risk factors include high blood pressure, obesity, smoking and diabetes, and it is thought the damage to the brain occurs as far back as childhood.

The three-year study into how Aboriginal Australians age, titled Koori Growing Old Well, was conducted across five urban and regional Indigenous communities in New South Wales.

They were La Perouse, Campbelltown, Kempsey, Nambucca and Coffs Harbour and included 336 participants, all over 60 years of age.

Aunty Margaret is an Aboriginal elder from western Sydney. She decided to get involved in the study after her husband John struggled with dementia.

She says his memory problems started 10 years ago and that he also had diabetes and heart disease. He died two years ago, after a heart attack.

"I noticed a difference in his attitude. It wasn't the John that I knew, the John that I married," she said.

"Things I asked him about at the time, he would forget five or 10 minutes later. It was sad.

"Lights would go on all over the place and I knew when the front door was being opened, so I'd get up and he would be sitting out in the front yard, all dressed, just sitting there."

The study found that Aboriginal people suffer from the same type of dementia as non-Indigenous Australians, with Alzheimer's disease affecting the greatest number of people, followed by vascular dementia.

There was a higher rate of dementia caused by head trauma, but alcohol-related dementia was rare.

Professor Tony Broe, a senior research fellow at Neuroscience Research Australia, led the study.

He says the results confirm earlier research in remote Aboriginal populations, including one in the Kimberley region of Western Australia.

But only about 30 per cent live in remote areas and Professor Broe says research needs to be undertaken in urban and regional areas, where the majority of Indigenous Australians live.

"Aboriginal people in urban areas have a high incidence of many of the risk factors that have been linked to dementia in studies around the world," he said.

"We feel that is sort of just an end result of what is happening to Aboriginal people.

"Why do they smoke too much, why do they get obese, why do they eat more than their non-Indigenous colleagues.

"It's because what happened to them in early life.

"Although Alzheimer's disease is such an organic disease, we believe that the social determinants of growing your brain well are very important."

Aboriginal Australians are three times more likely to suffer dementia than non-Indigenous Australians. ( ABC News )

'In denial'

The study was conducted between 2009 and 2012, with final data collection in October 2012.

While the analysis is still ongoing, preliminary results suggest the prevalence of dementia over 60 years of age is more than 13 per cent in Aboriginal Australians.

But Professor Broe says they are "a young, old group" with 73 per cent of those with dementia aged between 60 and 70, compared with non-Indigenous Australians where the majority are over 70.

As such they had to "age adjust" the figures.

"We found the rate is 21 per cent, which is three times the non-Indigenous rate and I think that is the more accurate figure to look at the burden of dementia," he said.

The results have prompted doctors to call for appropriate services tailored specifically for the Indigenous community.

Colleen Cawood is an Aboriginal health worker based in Sydney who helped recruit patients for the trial.

She says some Indigenous people are reluctant to share their health concerns.

"They just like to stay private and keep their health issues confidential within the family. They don't want it what we call 'going on the Koori grapevine'," she said.

And Ms Cawood says some people do not want to accept the diagnosis when it is given.

"They are struggling. Some of the families are in denial, saying he hasn't got dementia and we try to tell them he shouldn't be left alone," she said.

She says most Indigenous families want to care for their loved ones with dementia at home, rather than put them into aged care.

Professor Broe says the findings will be used to develop education and services for older Indigenous people with dementia and for their families.

Glenn Rees from Alzheimer's Australia says the findings show how important research is.

"This would help us provide culturally appropriate services for Australia's Indigenous community," Mr Rees says.

Aunty Margaret is now an Aboriginal Dementia Knowledge Elder with the project, providing information and a point of contact for the local community in Campbelltown.

She says there has been a change in attitude towards dementia and that it is important to have services targeted specifically for Aboriginal people.

"They need somewhere where they can come to get information and they know they can come to me," she said.

"They like that, that they can come somewhere and talk to someone about their problems, a familiar face, especially an Aboriginal person they can sit down and talk to."