Andrew Hayen, professor of biostatistics at the University of Technology Sydney, said dementia overtaking heart disease among this age group was “bound to happen at some stage”. “Since 1990 the death rate for dementia has been going up about 3 per cent a year, and there has been a bigger increase in women,” he said. “It’s probably the only cause of death that is having such a big increase.”

Kaele Stokes of Dementia Australia, the peak body for people living with the disease, added that dementia cannot be treated in the same way as heart disease. “For dementia we do not have a treatment to slow, modify or stop the progression of the disease at this stage,” she said. “There is not the surgical intervention like there is for heart disease.” Dr Stokes said while some people were genetically predisposed to be at a higher risk of dementia, “modifiable” factors such as a poor diet, a lack of exercise or a decline in social interaction in later life played a bigger role in increased risk. Loading Replay Replay video Play video Play video “What is good for your brain is good for your heart, and vice versa,” she said. “There are some shared risk factors for chronic diseases like diabetes, heart disease and stroke that also underpin your risk of developing dementia.”

Dr Stokes said keeping your brain active into later life can also reduce dementia risk, “not just doing the crossword every day but actually stretching your brain”. She said crosswords might not demand your full concentration once you learn the common tricks for solving clues, but that the challenge of learning a new language required far more brainpower. Alan Lopez of the University of Melbourne’s School of Population and Global Health said there was another factor in the rise – increased diagnosis of dementia could mean doctors were more likely to attribute the disease as a person’s cause of death. Loading And there are about two dozen municipalities Australia-wide where dementia is the leading cause of death, including Sutherland Shire in Sydney, Holdfast Bay in Adelaide and South Perth.

These are all relatively affluent inner-city areas, but this does not mean people in these areas die of dementia at a higher rate than the rest of Australia. In fact, it's quite the opposite: people in these municipalities tend to be healthier and live longer, so the rates for many common causes of death are lower than other parts of the country. Use the interactive below to see the most common causes of death in your area over the past five years, and how death rates for certain diseases or cancers compared with the rest of the country: Heart disease has long been the biggest killer of Australians and showed up as the culprit on about 12 per cent of deaths in 2017.

It is the leading cause of death in about 90 per cent of local government areas, and is the biggest killer irrespective of socio-economic status or remoteness. However, rates of heart disease tend to be higher in poorer areas and remote areas. Professor Lopez said the death rate from heart disease had been dropping since the 1970s thanks to tobacco control, better diets and health promotion. But he said the rate of decline (the extent to which heart attack deaths were dropping year on year) had slowed in recent years. “We are running out of room to get more gains, and we are getting to the point now where we are facing bigger challenges, and obesity is the obvious one.