The limits of the human lifespan have been the subject of long-standing discussion among scientists. Despite previous studies examining human longevity and life span, it still remains a puzzling mystery.
How Long Can People Live?
According to Live Science, though the bar has been set at 150 years, nobody has gone beyond this record in the last 25 years. The closest one was Jean Louise Calment, who lived to be 122 years old.
David McCarthy, an assistant professor of risk management and insurance from the University of Georgia, notes that because of this, several people have argued that the maximum longevity has indeed been met.
In a recent study, McCarthy and his team say that this record could be broken in the next 40 years. Rather than proposing an exact maximum age, they utilized a mathematical model to gauge trends in mortality in the coming years. Their study was published in the PLOS One journal.
The researchers looked into the mortality data of over millions of people from 19 countries who were born from the 1700s until the late 1900s. To proceed, they adjusted an existing mathematical model to see how the mortality rates of people who are 50 to 100 years old were different among people who had varying birth years. This information was then used to predict the age that people could reach.
Mortality Rates
According to their model, mortality rates could exponentially increase for those who are over 50 years old. These rates also plateau at remarkably old ages.
This model can provide hints as to whether humans are close to the maximum possible lifespan. If this were indeed the case, one might expect mortality rate decreases among the young to be accompanied by mortality rate increases with age. They discovered that was the case for those who were born before the year 1900.
On the other hand, among those born from 1910 to 1950, mortality rate trends were quite different. Compared to the pre-1900s group, this group attained an age-related plateau at remarkably older ages. They also did not see any spontaneous mortality upticks in old age to accompany mortality decreases observed among the younger.
McCarthy notes that these results show that humans have not yet achieved their maximum life span. The researchers project that longevity records could be broken within the next four decades.
What About Biological Factors?
As per Live Science, the model's major limitation is that it does not take into account the biological factors related to aging. Cellular aging, vulnerability to age-related illnesses, and other factors are all ruled out of the picture. The model also does not acknowledge how medical advances could lengthen the human life span in the coming years.
Laurence Mueller and Michael Rose, who are professors from the University of California, Irvine, and did not participate in the study, note that they have believed for a long time that addressing aging-related concerns is best catered to through lab research involving animal cohorts the the analysis appears to be intriguing.
Stuart Jay Olshanky, a professor of epidemiology and biostatics from the University of Illinois Chicago who did not participate in the study, says that the heart of lifespan is primarily biological and not mathematical.
While McCarthy accepts these strong limitations, he still thinks that the model could provide insight regarding mortality patterns in the future, especially since it aligns well with historical mortality data.
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