Prevention is not a substitute for cure.

The better we get at preventing disease, the more we have to spend on hospitals. And life expectancy cannot improve forever.

Where it all began: the Broad Street pump

It’s such a simple song that any politician can sing along: “It’s better to have a fence at the top of the cliff than an ambulance at the bottom.”

This is the approach to health policy that those hopeful politicians think will keep people out of those expensive and troublesome hospitals, so we can save money and keep people well at the same time. It looks, and is, too good to be true.

It arises from a fundamental misunderstanding of what disease prevention is, and how much money the country is putting into it. Even the government's own National Preventive Health Strategy claims that Australia spends only 2% of its health budget on prevention, and that’s nowhere near enough. If that was true, of course it wouldn’t be enough. But it’s not true.

According to the Australian Institute of Health and Welfare, $7.5 billion was spent on public health by governments and other entities in 2022-23. That’s 3.2% of the country’s total recurrent expenditure on health.

Public health is largely about trying to change people’s behaviour: smoking, vaping, drug use. It’s also about tracking communicable diseases and some screening programs. But many of the most important initiatives preventing disease fall well outside these areas and many are so long-standing that we don’t even recognise them within the health funding system. Take, for instance, sewerage.

In the beginning

The birth of modern disease prevention can be accurately, if symbolically, dated to 7 September 1854 when a London physician, Dr John Snow, persuaded local authorities to remove the handle of a public water pump in Broad Street, Soho. Snow, years before the discoveries of Pasteur and Lister were known, had doggedly traced the sources of the city’s regular cholera outbreaks to contaminated water supplies. He had developed techniques we would now recognise as epidemiology: the US National Institutes of Health define it as “the study of the determinants, occurrence, and distribution of health and disease in a defined population.”

John Snow: pioneer epidemiologist

Snow found that water companies on the affluent north side of the Thames filtered their water through sand and other firms, on the impoverished south side did not. And he noticed that the customers of the Vauxhall and Southwark Company were twice as likely to contract cholera as those of the Chelsea Company across the river.

Another incident – a collision between two ships on the Thames – spurred action when 16 of the survivors died, not of drowning but of disease, after being immersed in the filthy, lethally toxic river. Corpses of others were covered with sticky slime, bloated and quickly rotting.

A pioneer sewerage system, first proposed 25 years earlier, was finally begun. The river remained polluted but the streets and houses were very much healthier. Human waste no longer flowed into the water supply. Cholera and other diseases borne by filthy water became less common, then rare, and finally all but disappeared. Sewerage systems are still being built in cities and towns around the world and, everywhere they have been installed, are responsible for a spectacular decline in disease and death.

They have become so familiar that we no longer even count them as part of the health system. A great deal of money is spent on the safe disposal of waste but almost none of it counts as part of the nation’s spending on disease prevention.

The same is true of most of the improvements introduced over the past century and a half: better diet, education, higher wages, building codes and many more. If we counted the money spent on establishing and maintaining these initiatives as they should be counted – as key elements of population health – we would have a very different idea of what the nation is actually spending. It’s far more than 3% of the total health budget.

Prevention or treatment?

Almost 3,000 people every year undergo cardiac artery bypass surgery to avoid potentially fatal heart attack. In public hospitals alone, they cost $1.1 billion a year. Are those operations treatment or prevention? In the funding figures, they have nothing to do with prevention. So what are they?

Are the statins, drugs which lower cholesterol in the blood and help prevent heart attacks and stroke, not about prevention either? Officially, they are not. But the top four statins on the PBS cost the nation around $5 million a year.

Are the anti-hypertensives, drugs that lower blood pressure to prevent heart attack and stroke, treatment or prevention? The four most-prescribed drugs in this category cost $285 million a year. But they don’t count either.

The new diabetes and weight-loss drug, semaglutide, is prescribed to treat and prevent type-2 diabetes and to control obesity. There were 2.4 million PBS prescriptions in 2023-24, costing the government $285 million and patients another $36 million. But according to the official categories, it is not counted as having any preventive value at all.

Whatever classifications we use, the results have been impressive. At the end of the 19^th century, a boy born in 1890 had an average chance of dying at 47 and a girl at 51. See how that’s changed: an increase of 72% for males and 68% for females.

Australia’s generally high standard of living has helped make this country’s life expectancy the second-highest in the world, behind only Japan. This has been attributed to very low infant mortality, relatively low mortality from alcohol and drugs, a strong health system and – compared with many other nations – less economic inequality.

Much of the earlier improvement in life expectancy in Australia and elsewhere were the result of the rapid decline in infant deaths. This cannot be traced to any single measure. Many factors produced the results we now accept as normal. At the beginning of the last century, children aged four or under accounted for a quarter of all deaths. That’s now down to 0.6%.

Any substantial improvement in infant mortality is no longer possible. This means improving overall life expectancy is now much harder than it was: it will be about keeping older people alive for longer. A further challenge will be the quality of those longer lives. How healthy and happy will those people be?

We tend to take these things for granted, but that vast range of measures designed to make our lives longer and better have so far given us an extra 34 years of life since the late 19^th century. The graph flattened between the 1930s and the 1970s, particularly for men, most probably because this period was the heyday of the tobacco industry. When anti-smoking campaigns and legislation took hold, the line resumed its upward trend, though with slower improvement than earlier in the century.

Again, no single intervention stands out. There has been, and remains, a gradual but consistent trend to longer average life.

The greatest improvements have been in the prevalence of cardiovascular and infections disease. The decline of smoking, along with health initiatives such as statins and anti-hypertensives, as well as improved treatment for non-fatal cases, produced a dramatic fall in deaths from heart attack and stroke.

The decline in infectious disease began well before the introduction of antibiotics in the 1930s and 1940s. Improved environmental conditions were arguably even more significant. The outbreak of bubonic plague in a poor and overcrowded slum area of Sydney in 1900 infected 303 people and killed 103. It made barely a blimp in the overall figures. But it demonstrated eloquently the importance of environmental health. Even AIDS and COVID-19 did not return infectious disease to its former place in the hierarchy of fatal illnesses.

Cancer has been more intractable. The widespread reduction on smoking rates have taken decades to change the direction of deaths from lung and other smoking-related cancers.

Even by the 1970s, smoking was in decline. But then an even larger, sustained fall occurred when the risks of smoking became known and public health measures were taken.

But even now, smoking remains a major cause of illness and death. In lung cancer, still the worst of all the smoking-related diseases, 30.6% of the burden of disease (a combination of illness and death) is due to tobacco.

Compared to most of the world, Australia is doing well. Although 6.8% of all deaths in this country can still be attributed to smoking, that’s less than in most other nations.

As old diseases decline, new ones appear

Disease control is a never-ending process. People who would once have died before reaching old age now live on. Cardiovascular disease is still the most common cause of death but is in a long, pronounced decline. But it is now being overtaken by dementia, because far fewer people in the past lived long enough to develop it.

In just 14 years, the rate of deaths from dementia has increased by 76% overall, by 68% for women and by 89% for men. Apart from a slight decline during the pandemic – probably due to so many older people dying first of COVID-19 – the increasing rates show no sign of slowing. According to the Australian Institute of Health and Welfare, dementia care in 2020-21 cost $3.7 billion. This group of diseases affects an estimated 411,000 people, a figure which is rising quickly.

Dementia is only one of the many chronic diseases affecting Australians, particularly as they age. Like so many health conditions, the poorest suffer far more than those with more money. The prevalence of chronic illness is strongly associated with obesity, smoking, insufficient consumption of fresh food, less education and inadequate access to healthcare.

Preventing disease increases hospital costs

Paradoxically, the better we have become at preventing disease, the more people end up in hospital. We’ve already seen why. Someone who might have died at 60 of a catastrophic heart attack, suddenly and cheaply, may now live to 85 or 90. But on the way, they will amass a range of chronic illnesses requiring high-level care in hospitals and aged care facilities. And a high proportion of someone’s lifetime hospital costs accrue in the last two or three years of life. One Australian study found the care of people over 65 in their last year of life accounted for 8.9% of all hospital costs. As we all die eventually, we can all expect to accrue those needs for hospital treatment and the costs that come with them.

That’s not the only reason for the ever-increasing rate of hospital admissions, but it is one of them. In just the 12 years to 2023-24, the number of people admitted to public hospitals has increased by 34%.

Now what?

It is now harder than ever to make significant further inroads into disease prevention and life expectancy. Most of the big changes, and all the easy ones, are already in place. Infant mortality has effectively been conquered. Smoking rates are down so far that even total elimination of tobacco would not have the impact of past decades, though residual benefits of past successes, particularly in cancer, will continue. Death rates from infectious disease, even during a pandemic like AIDS and COVID-19, no longer  shift the overall trajectory of life expectancy. We can expect cardiovascular disease will continue its precipitous and welcome fall as a major cause of mortality.

Cancers are far more intractable. Without huge breakthroughs in treatment and early detection, which have been so elusive for so long, any improvement will continue to be incremental, painful and expensive. And there is no guarantee that cancer rates will go forever downwards. Worrying increases in cancer incidence among younger adults are being seen globally. Although numbers are still relatively low, they are increasing rapidly in all age groups, particularly among people in their 30s and 40s.

The cause of this trend is the subject of much speculation and little firm knowledge. We are only now being told about the ubiquitous nano-particles of plastics that are increasingly present throughout the bodies of most of the people on Earth. We do not know what effects they are having on human health, but all the plastics ever produced are still present in some form, breaking down into ever-smaller, potentially more dangerous, fragments.

Nor do we know much about the effects on human and planetary health of the hundreds of thousands of chemicals to which we are exposed. A comparative few have been conclusively shown to be dangerous and often carcinogenic, but what about the others? It would be naïve to assume they are all benign.

Vascular dementia is presumably in decline, along with other cardiovascular diseases, though it’s hard to tell from the available data. Alzheimer’s, though, continues to elude both prevention and decisive treatment. The bulk of drug development has concentrated on attacking the proteins that form in the brain. So far, the results have been disappointing and the disease will continue to negate advances in the prevention and treatment of other diseases.

The initial weight-loss drugs, such as semaglutide, promise an effective pharmaceutical intervention in the obesity “epidemic”. The drugs currently available are unlikely to provide a population-wide solution and we await the second, third and fourth generations to minimise side-effects, improve efficacy and – perhaps – reduce costs.

Unfortunately, we cannot assume that initiatives from our political leaders, their bureaucrats and favoured experts will be wise and effective. An example is the extraordinary mishandling of tobacco policies. Al Capone could have told them that prohibition does not work, but that’s what bumping the price of a packet of 20 cigarettes up to an average of $41.50 has done.

The tobacco market is now out of control, taken over by organised crime syndicates that import cheap cigarettes, often with higher tar content, at around $15 a packet. A recent study estimated the illegal trade now provided 50% of all tobacco to Australia’s 2.7 million smokers, making around $10 billion a year. All these figures are still rising rapidly. Governments are, once again, relying on law enforcement. It will be just as effective as it has been in the past to enforce bans on liquor, cannabis and other illegal drugs, but the effects on human health are predictable and dire.

A key to future progress would be a successful transformation of the social and economic disadvantage that underly so much illness and premature death. But those issues – education, income, poverty, social dislocation, lack of access to affordable fresh food, and so on – are, like so much in this field, intractable. We could achieve much by reducing inequality, but there are powerful forces working for the opposite outcome.

We cannot assume that those massive historical improvements in life expectancy will continue. So much has already been achieved that the challenge of adding to those gains is daunting. Human lifespans are limited, and we are beginning to push the boundaries. At some point – not quite yet, but some time – the limits of public policy, healthcare and the human body will be reached.

We cannot know when the crunch will come, but come it will.