Melbourne woman Mithrani de Abraw Mahadeva first noticed something wasn't right when she kept stumbling and losing her balance on her daily walks.

"I thought, this is not normal," Ms Mahadeva said.

"So, I made an appointment to see my primary physician."

After a round of tests, the 71-year-old was referred to a geriatrician who immediately recognised the signs of dementia.

But she needed further brain scans to determine which type.

During these investigations, Ms Mahadeva's symptoms got worse. She remembers seeing and hearing things that weren't there.

"I once saw my bedroom wall like a canvas, it was moving. I even touched it to see if it was moving," she said.

Ms Mahadeva was eventually diagnosed with several types of dementia known as Vascular Lewy and Parkinsonism — which causes delusions and movement issues.

That was several years ago, and while she's been receiving treatment and care, things like reading are a real challenge.

"I still love reading, but I can only read a few words, with a picture," Ms Mahadeva said.

Rising dementia cases

She's one of more than 401,000 Australians living with dementia, according to data released by the Australian Institute of Health and Welfare.

In people aged over 65, one in 12 people have the condition.

The data also shows the number of years of healthy life lost to dementia has soared by more than 60 per cent in the past decade.

It's overtaken coronary heart disease as the leading cause of burden of disease and premature death in people aged over 65. Overall, dementia is the second leading cause of death in 2020.

"Alzheimer's disease and other dementias is increasingly common because our population is becoming older," associate professor Michael Woodward explained.

Dr Woodward is the director of aged care research at Austin Health and is a medical advisor to Dementia Australia.

He is not surprised the institute's data shows the number of people with dementia will double during the next 35 years.

"What we have to take from these figures, is we need to be better prepared, we need to have better understanding of what causes dementia, better risk reduction strategies and better ways of preventing dementia," Dr Woodward said.

The institute's report identified a range of risk factors for dementia, including chronic diseases such as diabetes and heart disease, smoking, drinking alcohol, physical inactivity, depression, deafness and even air pollution.

These are all things that can be minimised to prevent dementia, according to Dementia Australia CEO Maree McCabe.

"Diet is really important, we recommend the Mediterranean diet, exercising our body and our brain," Ms McCabe said.

Cost to health system

The report found that in 2018-19, $3 billion was spent directly on health and aged care services for people with dementia, and in 2020-21, around 25,500 hospitalisations were due to dementia.

Dr Woodward said the growing prevalence of the condition will put a huge strain on our already troubled health system.

"We're going to see an increasing number of people interacting with health care and residential aged care," he said.

"We need to understand the effect this has on everybody; family, friends, paid carers and society in general. So, we need better approaches."