People are living longer than ever—but we can't keep pushing our life expectancy higher and higher, according to a study, claiming our lifespan has an upper limit.
As we get older, our risk of dying climbs, of course. But curiously, data show this risk appears to slow and level off as we reach the end of our lives, both for people and some animals.
In a phenomenon called "late-life mortality deceleration," we effectively appear to stop biological aging as we get closer to death. Scientists are not sure why this happens but have offered explanations, with some saying it has an evolutionary basis that is coded into our bodies. This has stoked debate on whether technology and medical interventions could help us live years longer than we currently can, and maybe even forever.
But a study published in the journal Plos Biology has offered an answer as to how this "deceleration" pattern occurs: simple statistical errors.
By analyzing previous research, Saul Newman of Australia National University found errors in the data, including in demographic sampling and birth and death records, meaning individual and subsequent studies were misleading. One example included mistakes in people's ages, with some noted as younger or older than they were. So, when these people die and population data is assessed, it can create a plateau effect.
Newman told Newsweek: "We can never live forever. But if we are to ever live indefinitely, we have to understand the real patterns of aging. That is what I am fighting for."
What surprised Newman most about his research was its "simplicity," he said.
"I dropped my car at the mechanic. I bought a coffee. I caught the 314 bus. Between the coffee and my bus stop, I solved the problem," he said.
Newman argued that for "over 20 years, scientists have been fighting over an error distribution."
"Errors alone can explain these patterns. Further explanations are not ruled out, they are just unnecessary."
Newman acknowledged that his study had its own limitations. When the plateau is eliminated, a small residual pattern remains in the data—and it's not clear why. "This small residual may be due to the imperfect method I use to estimate error rates, or it may be explained by other hypotheses," he said.
Newman hopes his research will stop scarce scientific funding from getting funneled toward anti-aging projects based on incorrect statistics. And he believes his research could help create treatments to ease the negative effects of aging more effectively, he said.
"By highlighting that we must focus, not on a stamp collection of exceptional cases of the very old, but on the ordinary aging of ordinary people... if we do this, we can work to alleviate biological aging: the one shared risk factor behind 85 per cent of human deaths," said Newman.
Other researchers have questioned Newman's explanation. In a separate study linked to the findings in Plos Biology, Newman homed in on a paper published earlier this year in the journal Science, which included 4,000 individuals in Italy.
"In all of Italy, only 200 to 400 typos, identity thefts and pension frauds a year are needed to generate the results" of the study, he said. "The authors have no capacity to rule out such errors." Kenneth Wachter, a co-author of that study, hit back at Newman, saying the number of errors he found was "wildly implausibly high."
Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Kashmira Gander is Deputy Science Editor at Newsweek. Her interests include health, gender, LGBTQIA+ issues, human rights, subcultures, music, and lifestyle. Her ... Read more
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