It's a debate that has attracted the attention of demographers for the past 30 years: Can human life expectancy continue to rise as fast as it did in the second half of the 20th century? While life expectancy probably stagnated between 20 and 50 years of age until the beginning of the 19th century, it did indeed experience a "boom" after the Second World War thanks to advances in medicine and public health, leading to a longevity revolution. For over 50 years, human beings gained up to three years of life expectancy per decade, while one or two centuries earlier it was one year.
According to a new study published Monday, October 7 in the journal Nature Aging, this exceptional rise in life expectancy has been slowing for the past 30 years in the countries where it is highest. According to the researchers, this slowdown is set to continue into the 21st century in the absence of any significant progress in controlling the biological aging process.
To support their study, the four American scientists focused their research on the eight countries whose populations reached the highest levels of life expectancy between 1990 and 2019 (Australia, France, Italy, Japan, South Korea, Spain, Sweden and Switzerland), as well as on the Hong Kong region and the United States, which constitutes a special case, since Americans' life expectancy has been slowing down since the 2010s and was put under a severe strain by the Covid-19 epidemic.
Their calculations show that, on average, these populations have gained only 6.5 years in 30 years, in other words, well below the previous period. Only South Korea and Hong Kong have experienced these exceptional rates of "radical lifespan extension," in other words, a gain of around three months every year. The case of Hong Kong shows that economic prosperity and its very strict anti-smoking laws were decisive factors.
'The glass ceiling of longevity'
"The slowdown is a byproduct of medical success," stated Jay Olshansky, professor of public health at the University of Illinois, Chicago, and first author of the study. "This happens when many more people survive to later ages when the biological process of aging becomes the dominant risk factor."
Since the 1990s, the epidemiologist has championed the idea that humanity is about to reach a kind of ceiling of longevity, caught up by its biological limits. Other demographers, such as James Vaupel, who died in 2022, theorized that these limits could be surpassed thanks to future scientific revolutions. "This article is a kind of post-mortem response to Vaupel," explained Carlo Giovanni Camarda, director of research at the French National Institute of Demographic Studies (INED), who was not involved in the study.
You have 45.62% of this article left to read. The rest is for subscribers only.