A new scientific paper states human life expectancy is increasing at a slower rate than it did in the 20th century after a study of 10 wealthy countries.
During the 20th century, improvements in public health and medicine resulted in “radical life extension”. With each passing decade, the average life expectancy at birth in some of the world’s longest-lived populations in high-income countries increased by around three years.
These increases in life expectancy were initially driven by reductions in the death rates of children, followed by declines in the death rates of middle-aged and older people. For instance, in the US in 1900, the average life expectancy at birth was 47.3; by 2000, it had increased to 76.8.
Now a report, published on 7 October in the journal Nature Aging, predicts people can only be expected to gain an extra 2.5 years over the next three decades.
The most likely explanation is humanity is now approaching the upper limit of its life expectancy, the authors of the study argue.
In other words, with more people surviving to older ages, the main risk factors for death are related to biological ageing, the gradual accumulation of damage to cells and tissues that inevitably occurs over time.
We know how to prevent children from dying of measles, but we can’t yet stop the biological clock that keeps ticking once that child reaches age 60, 70 and beyond.
Tackling one age-related disease at a time, for instance, by trying to develop cures for Alzheimer’s disease or cancer, is like putting on a “temporary survival Band-Aid,” said Jay Olshansky, lead study author and a professor of epidemiology and biostatistics at the University of Illinois Chicago.
These efforts to develop better treatments and, eventually, cures, can enable people to live long enough to experience aging, but they don’t tackle the root issue of ageing, he said.
In the study, Olshansky and colleagues investigated trends in life expectancy between 1990 and 2019 using national vital statistics data from nine regions with the longest-lived populations: Australia, France, Italy, Japan, South Korea, Spain, Sweden, Switzerland and Hong Kong. They also looked at figures from the US, as some scientists made specific predictions about radical life extension in the country, they wrote in the paper.
The researchers found that overall improvements in life expectancy decelerated across these 10 countries, particularly after 2010. Current birth cohorts have a small likelihood of making it to 100 with females having a 5.1% chance, and males an 1.8% chance.