Opinion shaper: Science: We cannot live forever

Recent data published Oct. 7 indicate that it is not plausible to increase the maximum human lifespan muchbeyond historical levels.

The oldest person with a documented birth date was Jeanne Calment who lived to 122.45 years and died in 1997. Now research contradicts the scientists who previously touted their goal of extending the human lifespan to 150 or 200 years or more by overcoming various human diseases and aging disabilities.

Sadly this study came just a few months after the death of Leonard Hayflick (May 20, 1928 to August 1, 2024), a distinguished professor of anatomy at the University of California at San Francisco and who studied human ageing. Hayflick studied human cells in cell culture and discovered that they underwent a limited number of cell divisions and then stopped dividing! This was soon labeled the “Hayflick limit.” Additional research indicated that this set a limit to the lifespan of higher organisms including humans.

Nevertheless, many medical researchers pursued improving human health with the expectation of also extending human lifespan.

The recent research by Olshansky and colleagues just published in Nature Aging (“Implausibility of radical life extension in humans in the twenty-first century”) used “demographic survivorship metrics from national vital statistics in the eight countries with the longest-lived populations (Australia, France, Italy, Japan, South Korea, Spain, Sweden and Switzerland) and in Hong Kong and the United States from 1990 to 2019….”

Their results essentially indicated that even in early history, a few individuals lived into old age, and the increase in average-age-at-death reflected more people living longer toward that maximum old age, but not an increase in the potential human lifespan.

In the 20th century, human life expectancy rose by nearly 30 years at birth in wealthier nations due to advances in medicine and better public health.

This mortality reduction was in folks’ early and middle ages. The Olshansky team calculated what would happen if all deaths before age 50 were eliminated today: the increase in human lifespan was only 1 ½ years. Simply, there are now more chances to live to an old age, but that upper age limit has not moved.

But there is a wide variation in chances to survive to age 100. Pre-pandemic data from 2019 showed only a few more than 2 percent of Americans reached 100. But in Japan, nearly 5 percent reached 100, and in Hong Kong 9 percent lived to 100.

The number of centenarians in wealthier nations will grow as medicine advances and standards of living improve. But the percentage hitting age 100 is predicted to top out at fewer than 15% of women and 5% of men, according to Olshansky.

But that level is not predicted for life expectancy in the U.S. which remains far lower than in comparable countries, in data calculated by researchers in the Health System Tracker released January 30, 2024.

They found the “U.S. has the lowest life expectancy among large, wealthy countries while it far outspends its peers on healthcare.”

While life expectancy in the U.S. and its peers increased from 1980 to 2019, COVID-19 caused a decrease in 2020. But by 2022, life expectancy rebounded in peer countries, but continued to decline due to excess covid mortality in the U.S.

CDC data confirm that peer country life expectancy at birth in 2022 was 82.2 years, slightly down from 82.7 in 2019. But life expectancy in the U.S. was 77.5 years, down from 78.8 in 2019.

Women on average also live longer than men worldwide. While the U.S. has a lower life expectancy than the rest of the high GDP world, the U.S. also has a larger gap between men and women. Data from the World Health Organization indicate that “by 2016, life expectancy for U.S. females (81.1 years) was 3.3 years lower than the average in the 16 peer countries (84.4 years), and life expectancy for U.S. males (76.2 years) was 3.7 years lower than the peer average (79.9 years). ….This trend accelerated rapidly after 2010 as life expectancy stagnated and then declined in the United States alone.”

The late Leonard Hayflick would probably be pleased to see research confirm the “Hayflick Limit.” He realized that our days to live have a biological limit, and modern medicine cannot extend that upper limit. Perhaps we should recognize it as well.