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Increase in life expectancy in rich countries is slowing: Why the breakthrough took 30 years
Life expectancy in wealthy countries is growing more slowly. After 30 years, a study shows that biological limits exist.
Increase in life expectancy in rich countries is slowing: Why the breakthrough took 30 years
Put aside the excitement about the growing number of people expected to live to be 100 years old. The increase in human life expectancy may actually be slowing. This is the finding of a study that analyzed mortality data from ten countries or regions over the past three decades 1.
“There are limits to how far we can push human survival time,” said study co-author S. Jay Olshansky, an epidemiologist at the University of Illinois at Chicago. “If you live long enough, you encounter the biological aging process.”
He argues that the era of radical life extension is over. But some researchers disagree, pointing out that medical science may yet find a way to expand the age limits.
Advances in public health and medicine in the twentieth century increased life expectancy by about three years per decade. However, Olshansky and others have long argued that this improving trend is unsustainable, despite optimistic projections that predict most children born in the 21st century could live to be 100 or older 2. However, it is difficult to confirm this because the only way to find out is to wait until enough people die or not.
Olshansky and his colleagues first published the idea in 1990 3 that there is a finite limit to human life expectancy. “We waited 30 years to test this,” he says. “And we now have definitive evidence that the limited lifespan hypothesis is correct.”
This evidence is based on the number of deaths reported in parts of the world with the current highest life expectancies, including Hong Kong, Japan, South Korea, Australia, France, Italy, Switzerland, Sweden, the US and Spain. The analysis looked at the period from 1990 to 2019 to avoid the distorting effects of the COVID-19 pandemic.
The team found that the rate of improvement in life expectancy in the decade from 2010 to 2019 fell below levels seen in 1990 to 2000. People still live longer, but not as much. In fact, in every population except Hong Kong and South Korea, life expectancy growth has slowed to less than two years per decade.
Overall, the study found that children born since 2010 have relatively low chances of living to 100 (5.1% chance for women and 1.8% chance for men). The most likely cohort to live to see a full century is women in Hong Kong, with a probability of 12.8%.
Can we overcome aging?
It's clear that further extending the average lifespan is difficult because it would require researchers to come up with solutions for diseases that affect older people, says Dmitri Jdanov, a demographer at the Max Planck Institute for Demographic Research in Rostock, Germany. Jdanov wrote an accompanying commentary to the work with his colleague Domantas Jasilionis. Both articles are published today in Nature Aging.
However, Jdanov thinks Olshansky is too pessimistic about possible progress. “Although another leap might be difficult, the rapid development of new technologies could lead to an unexpected health revolution,” he says.
A century ago, few researchers would have thought that child mortality could be significantly reduced, he says. Advances in vaccines, education and public health have since reduced the rate from more than 20% in 1950 to less than 4%.
“If we can't imagine something, that doesn't mean it's impossible,” says Jdanov.
The study also revealed what Olshansky calls a "shocking" decline in average life expectancy in the United States in the decade starting in 2010 - a trend seen in such a long-lived population only after extreme events, such as wars, since 1900. The decline in the U.S. is driven by rising mortality from conditions such as diabetes and heart disease among people ages 40 to 60.
“It shows that there is something very negative happening among certain population groups that is pulling the average down, because the wealthier and more educated subgroups are actually doing better,” Olshansky says.
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Olshansky, S. J., Willcox, B. J., Demetrius, L. & Beltrán-Sánchez, H. Nature Aging https://doi.org/10.1038/s43587-024-00702-3 (2024).
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Christensen, K., Doblhammer, G., Rau, R. & Vaupel, J. V. Lancet 374, 1196–1208 (2009).
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Olshansky, S. J., Carnes, B. A. & Cassel, C. Science 250, 634-640 (1990).