It’s a debate that has agitated demographers for thirty years: can human life expectancy continue to increase as rapidly as it did in the second half of the 20th century?my century ? While she was probably stuck between 20 and 50 years until the beginning of the 19th centurymy century, life expectancy has actually experienced a “boom” after World War II thanks to advances in medicine and public health, leading to a longevity revolution. For more than fifty years, humans gained up to three years of life expectancy per decade, compared with one year a century or two earlier.
According to a new study published Monday, October 7, in the journal Nature agingThis increase in exceptional life expectancy has stagnated for thirty years in the countries where it is highest. A slowdown that, according to researchers, should continue into the 21st centurymy century in the absence of significant advances in the control of 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 the Hong Kong region and the United States, which constitute a special case, since the life expectancy of Americans is the lowest since the 2010s and has been greatly affected by the Covid epidemic. 19.
Their calculations show that, on average, these populations have only gained 6.5 years in thirty years, that is, a level much lower than the previous period. Only South Korea and Hong Kong have experienced these exceptional rhythms described as“radical extension of life expectancy”a profit of about three months each year. The case of Hong Kong shows that economic prosperity and its strict anti-smoking laws were decisive factors.
“Glass ceiling of longevity”
“This observed slowdown is a consequence medical successsays Jay Olshansky, a professor of public health at the University of Illinois at Chicago and first author of the study. This occurs as more and more people survive into old age, when the biological process of aging becomes the dominant risk factor. » Since the 1990s, the epidemiologist has defended the idea that humanity was going to reach a kind of glass ceiling of longevity, surpassed by its biological limits. Other demographers, such as James Vaupel, who died in 2022, have theorized on the contrary that these limits could be overcome thanks to future scientific revolutions. “This article is a kind of post-mortem response to Vaupel”underlines Carlo Giovanni Camarda, research director at the National Institute for Demographic Studies (INED), who was not involved in the study.
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