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The day when one becomes octogenarian, nature grants a mathematical birthday present: a gradual reprieve to the ever – increasing probability of dying in the coming year
. the growing grinding of the joints and the ever increasing probability that the end is near. But an analysis of nearly 4,000 very long-term Italians suggests that the rising risk of imminent death continues to slow down until the age of 105. After that, the researchers estimate that the chances of seeing another birthday stabilize at around 50-50
Maybe it's "nothing to blow a trumpet," said Kenneth Wachter, demographer from the University of California at Berkeley. But at least the mortality rate is zero, suggest the data
Wachter and colleagues from universities of Italy and Germany published their findings in the latest edition of the journal Science .
For humanity in general, these findings suggest an intriguing, although largely theoretical perspective: that the maximum possible human lifespan – essentially, the design limit of the species – n '# 39; has not been reached yet. It can even be extended by means not yet discovered.
If the "oldest old" tells us how long we could live, then many centenarians could, in principle, age even more. And maybe even older with the good elixir.
"These data suggest that our gene pool is permissive," said Wachter. "Our bodies are not assembled so that at one point everything goes wrong."
Indeed, he said, there is reason to believe that some humans could beat the longevity record of 122 established in 1997 by Jeanne Louise Calm of France
The new research contributes to a debate that has preoccupied poets and philosophers as long as they put themselves to paper. For example, the historian Gaius Plinius Secundus, better known as Pliny the Elder, maintained a current account of people with long lives and reflected on the meaning of their longevity.
Scientists have been in the fray since at least 1825. The British mathematician and actuary Benjamin Gompertz has published the first models of human mortality and asked when, and if, we must die.
In the new study, the international team of demographers and statisticians has benefited from the proliferation of people who are living their 100th birthday. By calculating and analyzing the mortality rates of 3,836 Italians who lived to age 105 or older and combining them with existing data on mortality rates, the researchers created a model that reveals the statistical probability of death. every year of human life. from 65 to 105.
Demonstrated demographics show that after age 65, people are more likely to die each passing year. And the calculation is ruthless: every year after 65, the probability of death increases at a rate that is double what it was the year before.
But when the researchers added the 3,836 long-standing Italians to previous data, they saw that this doubling only withstood until the age of 80 years. After that, the rate of increase began to slow down.
For lucky humans who made it all the way up to 105, this annual increase in the likelihood of death seemed to stop.
The authors also showed that the annual mortality rate among over-105s decreased slightly with each successive year of birth, so that those born more recently tended to live longer.
This trend strongly suggests that longevity continues to increase. Over time, no limit has been reached, "wrote the team, which included the demographer James W. Vaupel of the Max Planck Institute for Demographic Research in Germany
" Our findings contribute to a recently revived debate about the existence of a fixed maximum lifespan for humans, "they added. In any case, he raises "doubt that any limit is still in sight."
For the epidemiologist of the University of Illinois S. Jay Olshansky, the evidence for the counter-argument – that there is a strict limit to the maximum human life "The conclusion they reached, namely that there is no upper limit to life, is unreasonable," said Olshansky, who was not involved in the new research .
By the time people reach these extreme ages, at least half are disappearing each year. And as there is so little to begin with, this harsh reality "tells us the real story," he says.
"If 100 people survive until the age of 110 billion – which is exactly what happened – what difference does it make if it's 50 or 60 who die before their next birthday? It is not convincing to use such a small difference, drawn from such a small human population, to conclude on the longevity of humans in general. Statistically, he says, "the tail of the distribution of survival does not move the dog."
This should be very clear to all those who have already been around seniors, he noted. "Human bodies are not intended for long-term use, and when we manage to make them work over the past hundred years, many age-related diseases accumulate," Olshansky explains. Medicine in New York believes that he saw the limit of human life span, and said that he stopped his ascending trajectory in the 1990s with the death of Calment. (The French attributed her longevity to the fact that she did not worry much and that she had a diet rich in olive oil, port wine and chocolate, which She used to consume more than 2 pounds a week.)
study published in 2016 in the journal Nature Vijg and her colleagues calculated that if scientists could gather 10,000 people who had reached the age of 110 – a big one – if only one of them should live beyond 125.
Vijg, who was not involved in the new study, praised the ability authors to generate a new and well-documented database of individuals with a very long life span.
But "their data does not corroborate the statement" that the maximum limit of the life of the human being is much greater than what it has already been, a- he said.
"There is a ceiling at the end of the day, there is a ceiling," says Vijg.
Vijg says he is "amazed" at the vigor of the scientific debate around a question if far from the reality of mere mortals.The outer limit of human life is an "intriguing scientific debate," he said.But improving the average lifespan of all human beings – by increasing gains in nutrition, creating new drugs and tackling the causes of infectious diseases – is a better way to spend one's energy. "doubt," said Vijg. "We can improve the quality of life and maybe to give more life to more people. "
What do the new figures tell us about life and death at the limits of human life?
Think of aging as if it were a treadmill : You walk in the 60s, and at the time of your 65th birthday, the speed at which e the steps move under your feet begins to accumulate.
With each passing year, speed increases. In fact, the rate of this change doubles each year
Do not follow and you die.
Around your 80th birthday, the rate of this increase starts to slow down. You are still more likely to die with each passing year that you were in the year before, but your treadmill does not accelerate as much.
And by the time you reach the age of 105 – surprise! – The annual animation ceases completely
Now imagine yourself in a gymnasium filled with treadmills, each occupied by people of different ages. The 105 years run faster than all young people. And they fall off their treadmills – dying – at a much higher rate than the 70s.
Indeed, only half of them arrive at 106.
But if they do, they make a little break: Their treadmills are still the fastest in the gym, but at least they do not go faster.
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