Middle-aged Australians need to treat their brain health like they do their superannuation to avoid the risk of dementia, says a leading expert.

A lack of awareness and widespread apathy is putting Australians at risk of damaging their brains as they age, a new study warns.

The report published by the Centre of Excellence in Population Ageing brings together the most recent research on cognitive ageing, including known risk factors.

It also identifies policy and research gaps.

Professor Kaarin Anstey, lead author of A Rapidly Ageing Australia: Cognitive Ageing And Decline Trends, said the research shows few people intend to change their behaviour to reduce their risk of dementia.

"We did a national survey and we found there are people who might believe in the benefit of risk factors but they don't intend to change their lifestyle," said Professor Anstey, CEPAR Chief Investigator and NHMRC Principal Research Fellow at NeuRA.

The report also addresses the issue of 'financial frailty'.

Professor Anstey said people's cognitive function declines in ageing at a time when they're having to make very complex financial decisions regarding superannuation and housing.

She said those with cognitive impairment are more susceptible to poor financial decision-making.

"At the moment there is no policy framework or anything in place to assist them through that," she said

"We need to think about developing more decision support for people and be able to assess whether people have the capacity to manage complex financial arrangements," said Professor Anstey.

There is also a gap in knowledge about the risk factors for the age-related brain disease, according to the report released at NSW Parliament House on Wednesday.

"People know about keeping your mind active, that's fairly widely known but there is very little awareness about the cardiovascular risk factors for dementia," said Professor Anstey.

Dementia is the leading cause of disability among Australians over 65 and the second leading cause of death in Australia.

The research shows the prevalence of dementia doubles every five years between the ages of 70 and 84.

Despite the possibility of dementia seeming so far into future at the age of 40, it really is something younger Australians need to start addressing now, said Professor Anstey.

The Seven Modifiable Lifestyle Factors Linked to Dementia Risk:

* Midlife hypertension

* Diabetes

* Low education

* Smoking

* Physical inactivity

* Mid-life obesity

* Depression