- Scientists understand the biological mechanisms of ageing now more than ever.
- Any successful treatment to reverse or delay ageing will aggregate benefits across multiple disease fronts.
- In dealing with an ageing society, the focus must expand beyond the current old to include the young and people in middle-age.
The widespread improvement in global life expectancy was one of the greatest achievements of the 20th Century. In 1900, life expectancy at birth was 32 years; by 2019 it had risen to 73. However, as life expectancy continues to rise new challenges emerge.
In high-income countries, most life expectancy gains are now driven by improvements in mortality rates after 70 years of age. This means more people are living to ages where their health is getting worse.
As a result, there has been a gradual shift in the disease burden from infectious diseases towards non-communicable diseases, the incidence of which rises with age. In 2019, non-communicable diseases accounted for nearly three-quarters of all deaths globally. Given that more than 75% of all non-communicable-disease deaths are in low- and middle-income countries, this is a global problem.
Today, most children born in high-income countries will live into their ninth decade, and possibly beyond. This represents a new reality for humanity. In 1816, for example, French children had a 1 in 4 chance of making it to 70 years; today life expectancy in France is higher than 4 in 5.
The probability of reaching the age of 80 has risen even more dramatically from 1 in 12, to 7 in 10. As for reaching the age of 90, that’s gone from a 1 in 100 long shot to a 1 in 3 probability.
The economics of ageing well
The fact that a child born today is more likely to live to old age makes ageing well a new health priority. In fact, it’s a multi-trillion dollar target. Imagine a health intervention that improved health and lowered mortality at every age such that overall life expectancy increased by one year. We calculate that such an intervention would be worth a staggering $37 trillion in present value terms in the United States (US).
That’s the total value of healthier ageing to the US population - both current and future - at an annual rate of $725 billion. Our research also shows that whilst longer lives are valuable, the most valuable health priority of all is to ensure that healthspan rises to match lifespan; and that the period many spend in poor health towards the end of life is made as small as possible.
Because ageing is a cumulative phenomenon, ageing well is a lifelong process. This process can be supported by critical shifts in public health, better individual life and career choices, and healthier living conditions. It will also require the development of new treatments that aren’t just aimed at specific age-related diseases but which target ageing itself.
This isn’t reflected in current funding practices. The US spends more than $4 trillion on healthcare annually but only $2.6 billion is allocated to the National Institute of Aging, which mostly focuses on dementia. Given the scientific progress being made in the field of ageing, and the scale of the future health challenge, more resources need to be invested.
Holding back the years
The need for more funding is based on recent scientific developments. Scientists understand the biological mechanisms of ageing now more than ever and agree on the factors that contribute to it. They include a loss of stem cells, decline in protein maintenance and recycling, DNA damage and genome instability, the accumulation of zombie-like ageing cells, and a decrease in the energy-generating activity of mitochondria.
Drugs that target these factors are already being developed in laboratories and biotech companies around the world.
These drugs are backed by new and emerging technologies, which can accurately estimate biological age. The ‘Horvath Clock’, for example, is an ageing biomarker that requires only a mouth swab or drop of blood to determine how quickly an individual is ageing, and to predict when they are likely to die if they don’t alter their trajectory through lifestyle changes or pharmaceuticals.
Scientists also have the ability to turn back time using a technique called epigenetic reprogramming, which restores cells to a more youthful state.
Researchers at the Sinclair and Serrano labs have proven that age reversal is possible in mouse and human cells, and they have been able to rejuvenate tissues such as eyes and brains. While these developments are still in their early stages, they hint at the extraordinary possibility that human tissue and organs could benefit from cell-rejuvenating treatments.
Advantages of age reversal
Research and treatments aimed at single diseases, such as cancer and dementia, are important. But a broader focus on delaying or even reversing ageing has considerable advantages.
Firstly, given the number of age-related diseases, any successful treatment to reverse or delay ageing will aggregate benefits across multiple disease fronts. And secondly, treatments that delay ageing are highly beneficial because they lessen the probability of disease. So, for instance, the value of surviving cancer is even greater if the risk of dementia also declines. This combination of longevity and wellness makes delayed ageing incredibly valuable compared to treatments based on single diseases.
Most children born in high-income countries today will grow to be old. As a global community, we must ensure that our response to an ageing population goes beyond supporting the elderly to ensuring that the current young become the healthiest ever future old.