Scientists have long debated the maximum possible human age, with previous research limit up to 150 years. But in the past 25 years, no one has surpassed the record for the world’s oldest person, set by Jean-Louise Calment, who died at the age of 122 in 1997.
“It has led people to claim that the maximum lifespan has been reached.” David McCarthy (will open in a new tab), assistant professor of risk management and insurance at the University of Georgia, told Live Science. In a new study, McCarthy and colleagues say they have found evidence that this longevity record will be broken within the next four decades. The team did not propose a maximum age that people could live to, but rather used a mathematical model to predict what mortality trends might look like in the coming years.
However, not everyone agrees with the team’s findings, experts told Live Science.
In a study published March 29 in the journal PLOS One (will open in a new tab), scientists analyzed data on the mortality of hundreds of millions of people in 19 countries born between the 1700s and the late 1900s, up to 1969. people of different years of birth. They then used this information to predict the age people might reach in the future.
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The model assumes that the death rate will rise exponentially after age 50 and then stabilize at a very old age, McCarthy said. Such modeling could provide a clue as to whether a person is approaching maximum life expectancy. If this were the case, then one would expect that any decline in mortality rates at younger ages would be accompanied by a faster increase in mortality rates with age, in order to maintain age limit, he explained.
The researchers found that this was usually the case among those born before 1900. However, the trends in mortality among people born between 1910 and 1950 appear to be different. This group reached an age-related plateau at an older age than the pre-1900s group, and they did not experience the sudden spikes in mortality in old age that accompany the decline in mortality seen at younger ages. This discovery indicates that we have not reached the maximum human lifespan, McCarthy said.
“We predict that in most of the countries we studied, the maximum age will increase dramatically in the future,” McCarthy said. “This will lead to longevity records being broken in the next 40 years or so.”
For example, the model suggests that a Japanese woman born in 1919 or later has at least a 50% chance of living to age 122 or older. And a Japanese woman born in 1940 or later has a 50 percent chance of surpassing 130 years of age. (The model roughly covered the next 50 years and did not predict that anyone in any country would be over 150 years of age during that time.)
However, the model has a serious limitation: it does not take into account the biology of aging. In other words, when predicting who has a good chance of living to 122, the model doesn’t take into account the fact that people’s cells age over time and they become more prone to age-related diseases like cancer. It also fails to recognize how advances in medicine could increase human life expectancy in the coming years.
“While we find this demographic analysis interesting, we have long believed that the best way to address the basic questions of when and how to stop aging is to conduct studies with large cohorts of animals that are kept in stable laboratory conditions.” Michael Rose (will open in a new tab) another Lawrence Mueller (will open in a new tab)UC Irvine professors who were not involved in the study told Live Science in an email.
“Lifespan is essentially a biological phenomenon, not a mathematical one,” he said. Stuart Jay Olshanky (will open in a new tab)professor of epidemiology and biostatistics at the University of Illinois at Chicago, who was not involved in the study.
McCarthy accepts these limitations, but “because the simple model we used matches historical mortality data very well,” he said he believes it can still provide useful insight into future mortality patterns.