Hoping to reach 100? You’re not going to like these new life expectancy projections

Let’s keep it 100 — your chances of becoming a centenarian are slim.

Medical breakthroughs, public health achievements and better diets led to steep increases in global life expectancy in the 1800s and 1900s. But startling new research finds this momentum has slowed and the biggest boosts to longevity may be in the rearview mirror.

“Most people alive today at older ages are living on time that was manufactured by medicine,” said lead study author S. Jay Olshansky, a professor of epidemiology and biostatistics at the University of Illinois at Chicago.

“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,” Olshansky added.

The analysis, conducted with researchers from the University of Hawaii, Harvard and UCLA, includes data from eight countries with the longest-living populations (Australia, France, Italy, Japan, South Korea, Spain, Sweden and Switzerland), Hong Kong and the US from 1990 to 2019.

Life expectancy at birth in these countries only increased an average of six and a half years since 1990, according to the study.

“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,” Olshansky said. “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.”

In the US, life expectancy was 77.5 years in 2022 — a slight bump from 75.4 years in 1990 and a dip from 78.8 years in 2019.

This new study doesn’t include data from the COVID-19 pandemic, which Olshansky said would have “significantly” stifled life expectancy gains recorded from 1990 to 2019.

More than 7 million deaths worldwide have been blamed on the virus.

“We did not want to include the effects of COVID on the estimates because this is a temporary influence on survival, and it would have made the percentage changes across time heavily influenced by a one-time event,” Olshansky explained to The Post.

Olshansky published a paper in Science in 1990 that argued it was “highly unlikely” that life expectancy at birth would exceed 85 because the most significant gains had already happened.

In the new findings, published Monday in Nature Aging, Olshansky says we should focus on slowing aging and extending healthspan, the number of years a person is healthy, not just alive.

“This is a glass ceiling, not a brick wall,” Olshansky said. “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.”

Dr. Maria Torroella Carney, professor of medicine and chief of geriatrics and palliative care medicine at Northwell Health, also believes the focus should be on improving and maximizing health at cellular and physiological levels from a young age.

“Our organ systems (liver, kidney, lungs, heart, nerve function) peak in function around age 30 and decline over time,” Carney, who co-wrote “The Aging Revolution” and was not involved with the latest research, told The Post. “We are just now learning about the cellular and physiological changes that contribute to this decline, such as inflammation, injuries, poor diets and lifestyles that may accelerate aging.”

In the US, the oldest living person is Elizabeth Francis, a Houston resident who turned 115 in July.

The Pew Research Center reported that the number of Americans who reach 100 years old and beyond is expected to jump from an estimated 101,000 people in 2024 — 0.03% of the population — to around 422,000 in 2054, about 0.1% of the population.

Olshansky said those centenarian cases will remain outliers that won’t significantly increase average life expectancy.

“It would be optimistic if 15% of females and 5% of males in any human birth cohort could live to age 100 in most countries in this century,” his report read.

How to increase your life expectancy

Olshansky shared some tips with The Post on how to age better.

• Avoid behavioral risk factors that shorten life such as smoking, obesity, drugs, a sedentary lifestyle and a poor diet.
• Listen to your doctors and take medications to treat disease.
• Consider this — how healthy you are at younger and middle ages predicts how healthy you’re likely to be at older ages.
• Exercise and diet work effectively not just to ward off disease but to enhance quality of life at all ages.
• One of the most powerful predictors of lifespan and healthspan is educational attainment.