The world is heading towards a slowdown in life expectancy growth in the current century

Mark
Written By Mark

After remarkable numbers in the last century, the increase in life expectancy has slowed significantly for 30 years in the countries where it reached its highest levels, and it cannot continue in the 21st century in the absence of any decisive progress to slow the effects of aging, as a population study showed Monday.

Until the mid-19th century, life expectancy at birth ranged between 20 and 50 years. In the following century, “advances in medicine and public health led to a revolution in life expectancy,” according to the study led by the American demographer S. Jay Olshansky, whose results were published in the journal Nature Aging.

While humans previously gained an average of one additional year of life expectancy over a century or two, the increase accelerated to an additional 3 years of life expectancy per decade during the twentieth century.

But does this progress have limits? In France, where former humanitarian doyenne Jean Calment is said to have died aged 122, life expectancy at birth in 2019 was 79.7 years for men and 85.6 years for women.

In 1990, researchers, most notably Professor Olshansky, predicted that there were limits to medical progress in the face of aging. On the other hand, others defended the theoretical absence of a biological limit on human lifespan.

“We can no longer achieve significant gains in life expectancy by relying on reducing diseases,” Olshansky told Agence France-Presse.

Mortality pressure

By basing its presentation on the statistics of the eight countries with the longest life expectancy at birth (Australia, South Korea, Spain, France, Italy, Japan, Sweden, and Switzerland) during the period 1990-2019.

Its residents are expected to live on average 6.5 years longer if they were born in 2019 instead of 1990. This is a much smaller gain than that recorded during the previous period.

According to the study, these results “indicate that humanity’s battle for long lives has largely ended,” although the majority of the world’s countries are still waiting to benefit from the progress in public health that rich countries have benefited from.

Demographer and epidemiologist Jean-Marie Robin, who was not involved in the study, explains to Agence France-Presse that the struggle to increase life expectancy falls victim to the “law of diminishing returns.”

The gains recorded in the twentieth century were primarily the result of significant reductions in infant mortality. By lowering this rate, “we immediately achieve significant gains in life expectancy,” says honorary research director at France’s National Institute of Health and Medical Research (Inserm).

He adds, “And then we gradually begin to reduce the mortality rate in middle age” and achieve gains in the mortality rate among the elderly born after World War II, to the point that “few people now die before the age of seventy.” Ultimately, the population benefits from the phenomenon of “mortality pressure” towards a higher age group. In other words, “reducing social inequality in the face of death.”

gerontology

According to the study, the remaining margin of progress was further reduced. In the countries included in the study, deaths from all causes and at all ages must be reduced by about 20% in order for the average life expectancy of women at birth to increase from 88 to 89 years.

For the population born in 2019, the chances of surviving to age 100 affect only 5.1% of women and 1.8% of men.

Which makes S. Jay Olshansky says, “The door that remains open to us is that of gerontology.” In the absence of any progress in this area, it would be better to favor “healthy life span over life expectancy.”

For his part, Jean-Marie Robin points out that there is still “effort to be made” to reduce the death rate among people between 75 and 95 years of age.