Want to know how you’ll die? Increasingly, the chances are it will be dementia

Freddie Mercury posed a question for the ages when he asked who wants to live forever.

The Queen frontman only made it to 45, but extending lifespans and, in some cases, actively de-ageing, has become a multibillion-dollar industry in recent decades.

Scientists have made progress in better understanding the human brain.Credit: istock

American tech multimillionaire Bryan Johnson, for instance, has won plenty of media coverage for trying to turn his 45-year-old body into something closer to that enjoyed by an 18-year-old. Spending an estimated $US2 million a year on tests and procedures, the team of doctors helping him resist the march of time say he’s succeeding with a body like a 40-year-old.

But reality has a habit of hitting you in the face. When it comes to ageing, Father Time never misses.

Since the start of the 20th century, the improvement in average life expectancy has been nothing short of miraculous. In 1900, an Australian man could expect 51 years of life, while a woman could hope for 55 years. For a non-Indigenous boy born today, the average lifespan is closer to 82, while for a girl, it’s more than 85. The situation for Indigenous Australians, sadly, is worse at around 72 for men and 76 for women.

This relatively recent sharp increase in life expectancy has prompted some scientists (and science fiction writers) to suggest triple-digit lifespans becoming the new normal is within reach.

But earlier this month, a team of experts led by Stuart Jay Olshansky, released a paper with the rather dispiriting title Implausibility of radical life extension in humans in the twenty-first century.

Researchers looked at predictions made about 30 years ago, when developed nations were enjoying big increases in life expectancies and were estimating that newborns would enjoy their 100th birthday, if not a 110th celebration.

At the time, it was assumed the large increases in average lifespans from the 20th century would continue on into the 21st. But in their research, Olshansky and his team instead found improvements have slowed sharply.

One of the reasons for the surge in the average between 1900 and 2000 was because of a huge fall in child mortality rates. Improved nutrition and medicine (including vaccinations against common childhood diseases), better sanitation and overall healthcare meant a baby born this century had a much better chance of surviving childhood than one born 100 years earlier. Those same types of improvements helped people in their later years survive longer.

But the research team also identified a growing problem. Of the 115,000 Australians who died in 1974, about 30 per cent (34,629) succumbed to heart disease. In 2023,the number of deaths from heart disease was almost halved to 17,000. Even better, the average age at which people die from heart disease has increased from 72.7 years in 1974 to 83.4 years in 2023.

While medical advances such as bypass grafts and early treatments for hypertension have literally added years to the lives of millions of Australians, the situation is very different for people suffering from dementia.

In 1974, there were just 338 deaths attributed to dementia. By 2023 that number had climbed to around 17,000 – a near 5000 per cent increase. One of the driving reasons for the increase is the lift in people living longer, accompanied by other factors such as diet.

According to the Australian Institute of Health and Welfare, the main risk factor for dementia is ageing. While it can occur in people under 65 (who now account for about 80 per cent of the population), the chance of developing dementia doubles every five to six years for people over that age.

While Olshansky and his team argue that “humanity’s battle for a long life has been accomplished” and that “more than a century of public health and medicine successfully allowing humanity to gain the upper hand on the causes of death that have, thus far, limited human lifespan,” the same research points to major economic and financial implications.

If most of us aren’t going to be playing golf or taking a scenic river cruise along the Rhine when we’re 102, we don’t need bank vaults filled with retirement savings.

And if the general population is going to be battling dementia in their 70s and 80s, governments have to direct health spending (and medical research) into ways to make life comfortable for this increasingly large number of people.

To look after those people will require an army of specially trained carers, whose work is already criminally under-appreciated by economists who haven’t found a way to properly value their efforts and governments who continuously treat the care sector as an afterthought of election year budget handouts.

The recent aged care royal commission blew the whistle on poor (bipartisan) policy choices, forcing both the Morrison and now Albanese governments to dramatically increase spending on the sector.

These examples are just the tip of the demographic iceberg when it comes to challenging existing mindsets about longevity, about the health system, and the jobs market. We need to have a nationwide conversation about these issues. But we’re not. Instead, we’re reading about Bryan Johnson spending millions of dollars and engaging in a near-incomprehensible lifestyle in the belief that he can cheat the Grim Reaper.

Shane Wright is a senior economics reporter and regular columnist.

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