Dec 20, 2021 06:36 PM
https://knowablemagazine.org/article/soc...-life-span
EXCERPTS: William John Thoms, an English author and demographer who had just written a book on human longevity, expressed skepticism of all such centenarian claims. A human’s maximum life span was about 100, Thoms asserted. Certainly no claim of an age over 110 had ever been verified. “Evidence of any human being having attained the age, not of 130 or 140, but of 110 years … will be found upon examination utterly worthless,” he wrote.
[...] Yet even today ... scientists still dispute what the oldest human age could ever be — and whether there is any limit at all. After all, more than a dozen people are alive today with validated ages over 110 (and many more that old are still around, just not documented). Yet in only one verified case has anyone lived beyond 120 — the French woman Jeanne Calment, who died in 1997 at age 122.
“The possible existence of a hard upper limit, a cap, on human lifetimes is hotly debated,” write Léo Belzile and coauthors in a paper to appear in Annual Review of Statistics and Its Application. “There is sustained and widespread interest in understanding the limit, if there is any, to the human life span.”
It’s a question with importance beyond just whether people lie about their age to get recognized by Guinness World Records. For one thing, absence of an upper age limit could affect the viability of social security and pension systems. And determining whether human lifetimes have an inviolate maximum might offer clues to understanding aging, as well as aiding research on prolonging life.
But recent studies have not yet resolved the issue, instead producing controversy arising from competing claims, note Belzile, a statistician [...] Some of that controversy, they suggest, stems from incorrect methods of statistical analysis. Their own reanalysis of data on extreme lifetimes indicates that any longevity cap would be at least 130 years and possibly exceed 180. And some datasets, the authors report, “put no limit on the human life span.”
[...] From age 50 or so onward, statistics show, the risk of death increases year by year. In fact, the death rate rises exponentially over much of the adult life span. But after age 80 or so, the rate of mortality increase begins to slow down (an effect referred to as late-life mortality deceleration). Equations that quantify changes in the hazard function show that it levels off at some age between 105 and 110. That means equations derived from lower age groups are unreliable for estimating life span limits; proper analysis requires statistics derived from those aged 105 and up.
Analyses of those groups suggest that by age 110 or so, the rate of dying in each succeeding year is roughly 50 percent (about the same for men as for women). [...] Depending on the details of the dataset ... a possible longevity cap is estimated in the range of 130–180. But in some cases the statistics imply a cap of at least 130, with no upper limit. Mathematically, that means the highest ages in a big enough population would be infinite — implying immortality.
But in reality, there’s no chance that anybody will beat Methuselah’s Biblical old age record of 969. The lack of a mathematical upper bound does not actually allow a potentially infinite life span... (MORE - missing details)
EXCERPTS: William John Thoms, an English author and demographer who had just written a book on human longevity, expressed skepticism of all such centenarian claims. A human’s maximum life span was about 100, Thoms asserted. Certainly no claim of an age over 110 had ever been verified. “Evidence of any human being having attained the age, not of 130 or 140, but of 110 years … will be found upon examination utterly worthless,” he wrote.
[...] Yet even today ... scientists still dispute what the oldest human age could ever be — and whether there is any limit at all. After all, more than a dozen people are alive today with validated ages over 110 (and many more that old are still around, just not documented). Yet in only one verified case has anyone lived beyond 120 — the French woman Jeanne Calment, who died in 1997 at age 122.
“The possible existence of a hard upper limit, a cap, on human lifetimes is hotly debated,” write Léo Belzile and coauthors in a paper to appear in Annual Review of Statistics and Its Application. “There is sustained and widespread interest in understanding the limit, if there is any, to the human life span.”
It’s a question with importance beyond just whether people lie about their age to get recognized by Guinness World Records. For one thing, absence of an upper age limit could affect the viability of social security and pension systems. And determining whether human lifetimes have an inviolate maximum might offer clues to understanding aging, as well as aiding research on prolonging life.
But recent studies have not yet resolved the issue, instead producing controversy arising from competing claims, note Belzile, a statistician [...] Some of that controversy, they suggest, stems from incorrect methods of statistical analysis. Their own reanalysis of data on extreme lifetimes indicates that any longevity cap would be at least 130 years and possibly exceed 180. And some datasets, the authors report, “put no limit on the human life span.”
[...] From age 50 or so onward, statistics show, the risk of death increases year by year. In fact, the death rate rises exponentially over much of the adult life span. But after age 80 or so, the rate of mortality increase begins to slow down (an effect referred to as late-life mortality deceleration). Equations that quantify changes in the hazard function show that it levels off at some age between 105 and 110. That means equations derived from lower age groups are unreliable for estimating life span limits; proper analysis requires statistics derived from those aged 105 and up.
Analyses of those groups suggest that by age 110 or so, the rate of dying in each succeeding year is roughly 50 percent (about the same for men as for women). [...] Depending on the details of the dataset ... a possible longevity cap is estimated in the range of 130–180. But in some cases the statistics imply a cap of at least 130, with no upper limit. Mathematically, that means the highest ages in a big enough population would be infinite — implying immortality.
But in reality, there’s no chance that anybody will beat Methuselah’s Biblical old age record of 969. The lack of a mathematical upper bound does not actually allow a potentially infinite life span... (MORE - missing details)