Predictions of ever-increasing life expectancy could be cruelled if we continue to trash our own habitat.
Life expectancy has improved steadily since the Industrial Revolution and there’s a pervasive assumption that it will continue to keep increasing.
Demographers will tell you that by the middle of the century, Australians can expect to live well into their 90s.
The arrival of covid has interrupted this trend, with life expectancy declining abruptly in 2020 in US[i] and nearly all the EU countries by between one and two years[ii], though notably not in Scandinavian countries (except for Sweden).
These predictions are based purely on the extrapolation of historic trends combined with faith that we will make the relevant medical advances to delay or even avert the illnesses of ageing. They ignore any changes to underlying drivers or determinants of our health.
Yet we know that non-communicable diseases are increasing and affecting younger age groups, mental ill health is increasing and there is rising social inequality. We know from the work of social epidemiologist Michael Marmot and others that increasing social inequality consistently worsens health outcomes across populations, especially in lower socioeconomic groups[iii].
Things may already have started to change. In fact, over the past decade there has been a slowdown in gains in many developed countries, including Australia[iv].
In some areas, life expectancy has even fallen (even before covid). As in the US, parts of the UK have seen life expectancy fall since 2014. (In the US, rising opioid abuse is a significant factor).
As in the EU, the disparity in life expectancy between the various socioeconomic groups has widened. The effects are occurring disproportionately in the most deprived populations.
Australia is similar in terms of population risk factors, with high rates of obesity/overweight and growing social inequality.
So what of the future?
In addition to challenges related to NCDs and inequality, as well as emerging threats such as antimicrobial resistance and the increasing risk of zoonotic diseases, there is the growing gorilla in the room: climate change.
Recognised by the WHO as the greatest threat to human health this century, we are now seeing the unequivocal impacts on human populations around the world. Rising exposure to heat and extreme weather events, changing patterns of infectious diseases and food and water insecurity, worsening air pollution, and growing rates of associated mental ill health[v].
Some effects are direct and obvious, some can be managed through adaptation. But unmitigated climate change is going to profoundly affect our health by interfering with the basic requirements and determinants of health.
Clean freshwater, clear air, the stable supply of nutritious food and materials, and the regulation of microbes, vectors and pests by natural systems. In addition to this, our built infrastructure and systems have been developed and designed to operate in the stable range of climatic conditions of the Holocene period (the past 210,000 years).
Like these natural systems and food systems, human infrastructure will be stressed and start to fail without urgent adaptation and mitigation to prevent unmanageable future conditions.
Within the health sector, services will become increasing stretched because of rising demand due to climate-related events while facing increased stresses. These include the disruption of supply chains and utilities, and the effects on its workforce.
Ironically, our current extended longevity and improved health outcomes are largely due not so much to modern medicine, but to advances in science and engineering, public health interventions and infrastructure in improving the social and environmental determinants of health: clean water, hygiene, sanitation etcetera.
By the early to middle 20th century, as we became more aware that air pollution was having large-scale health impacts, regulations were enacted (such as the UK smokeless fuel acts in the late 1950s) to restrict the combustion of fossil fuels in urban areas, resulting in immediate health gains.
We now know that the particulate pollution from our cars and power stations is responsible for more than 8 million – or one in five – deaths globally each year[vi] from heart disease stroke, respiratory diseases, lung cancer, premature births and low-birthweight babies (and others).
Reducing these emissions would improve population health and save millions of lives in the short term as well as significantly reduce greenhouse emissions. Even in Australia, with relatively good air quality, there are around 5,000 premature deaths each year[vii] and a significant burden of ill health.
There are other health co-benefits from mitigating climate change, such as improved physical activity with less car travel, better and more sustainable diets, and urban design that makes cities cooler, greener, and more walkable and inclusive.
If we want to maintain and improve future health and lifespans, it is not likely to happen unless we address the underlying determinants of health. Governments must act, as they have in previous times in response to evolving scientific understanding.
Rather than spending more than 98% of health budgets on treating existing illness, it will mean refocusing and spending on prevention and public health, reducing health and social inequality, and facilitating healthier food, transport and health systems. It will also mean starting to plan for the now unavoidable climate impacts as well as acting meaningfully to prevent the increasingly unmanageable effects that would undermine the gains we have made over the past two centuries.
George Crisp is a Perth-based GP and a member of Doctors for the Environment Australia
[i] https://www.cdc.gov/nchs/pressroom/nchs_press_releases/2021/202107.htm
[ii] https://ec.europa.eu/eurostat/en/web/products-eurostat-news/-/edn-20210407-1
[iii] Marmot, M. Fair society, healthy lives (The Marmot Review): Strategic review of health inequalities in England post-2010. (2010) ISBN 9780956487001
[iv] Alan D Lopez and Tim Adair. Med J Aust 2019; 210 (9): 403-409. || doi: 10.5694/mja2.50144
[v] https://www.who.int/health-topics/climate-change#tab=tab_1
[vi] https://www.sciencedirect.com/science/article/abs/pii/S0013935121000487
[vii] https://www.sciencedirect.com/science/article/abs/pii/S0013935121000487
