Why life expectancy gains have slowed down despite medical advances

By Stephen Beech via SWNS

Life expectancy gains are slowing despite medical advances, according to new research.

How long people live increased rapidly through the 19th Century and first half of the 20th Century thanks to healthier diets, medical advances and other improvements.

Some scientists even predicted in 1990 that those rapid gains would continue - leading to “radical life extension” beyond 100.

But a new analysis, published in the journal Nature Aging, proposes that we may be nearing the limit of human longevity.

The American research team says that, after nearly doubling over the course of the 20th Century, the rate of longevity increase has slowed "considerably" over the last three decades.

They found that, despite frequent breakthroughs in medicine and public health, life expectancy at birth in the world’s longest-living populations has increased only an average of 6.5 years since 1990.

That rate of improvement falls far short of some scientists’ expectations that life expectancy would increase at an accelerated pace in the 21st Century and that most people born today will live to be 100.

The research suggests that humans are approaching a biologically based limit to life.

Lead author Professor Jay Olshansky, of the University of Illinois School of Public Health, says the biggest boosts to longevity have already occurred through successful efforts to combat disease.

He said that leaves the damaging effects of aging as the main obstacle to further extension.

Olshansky said: “Most people alive today at older ages are living on time that was manufactured by medicine.

“But these medical Band-Aids are producing fewer years of life even though they’re occurring at an accelerated pace, implying that the period of rapid increases in life expectancy is now documented to be over.”

He says that also means extending life expectancy even more by reducing disease could be harmful if those additional years aren’t healthy years,

Olshansky said: “We should now shift our focus to efforts that slow aging and extend healthspan.”

He explained that "healthspan" is a relatively new metric that measures the number of years a person is healthy, not just alive.

The analysis, conducted with researchers from the University of Hawaii, Harvard and UCLA, is the latest chapter in a three-decade debate over the potential limits of human longevity.

In 1990, Olshansky published a paper in the journal Science that argued humans were approaching a ceiling for life expectancy of around 85 years of age and that the most significant gains had already been made.

Others predicted that advances in medicine and public health would accelerate 20th-century trends upward into the 21st Century.

But, 34 years later, evidence reported in the 2024 Nature Aging study supports the idea that life expectancy gains will continue to slow as more people become exposed to the detrimental effects of aging.

The study looked at data from the eight longest-living countries and Hong Kong, as well as the United States - one of only a handful of countries that has seen a decrease in life expectancy in the period studied.

Olshansky said: “Our result overturns the conventional wisdom that the natural longevity endowment for our species is somewhere on the horizon ahead of us - a life expectancy beyond where we are today.

“Instead, it’s behind us - somewhere in the 30- to 60-year range.

"We’ve now proven that modern medicine is yielding incrementally smaller improvements in longevity even though medical advances are occurring at breakneck speed.”

He says that while more people may reach the age of 100 and beyond in this century, those cases will remain "outliers" that won’t move average life expectancy significantly higher.

That conclusion pushes back against products and industries, such as insurance and wealth-management businesses, which increasingly make calculations based on assumptions that most people will live to be 100.

Olshansky said: “This is profoundly bad advice because only a small percentage of the population will live that long in this century."

But he says the findings don’t rule out that medicine and science can produce further benefits.

Olshansky says there may be more immediate potential in improving quality of life at older ages instead of extending life.

The research team suggest that more investment should be made in "geroscience" - the biology of aging, which may hold the seeds of the next wave of health and life extension.

Olshansky added: “This is a glass ceiling, not a brick wall.

“There’s plenty of room for improvement: for reducing risk factors, working to eliminate disparities and encouraging people to adopt healthier lifestyles - all of which can enable people to live longer and healthier.

"We can push through this glass health and longevity ceiling with geroscience and efforts to slow the effects of aging.”