Observations of the oldest inhabitants of Italy showed that the probability of their death ceases to increase at the 105th year of life. This suggests that there is no hard limit to the maximum life expectancy. This conclusion was reached by scientists who published an article in the journal Science.
“As a rule, the chances of dying increase as the person's age and health deteriorate. We found that this trend suddenly stops at 105 years of age - the elderly Italians we observed died equally often at 105 and 110 years old. This idea of a 'death plateau' has received a lot of criticism in the past, and we have proven it to be true,”said Kenneth Wachter of the University of California at Berkeley (USA).
The typical duration of human life has never been constant - before the birth of civilization, it ranged from 20 to 30 years, and then, as science and medicine developed, it grew steadily. Today, in most countries of the world, people live for more than 60 years, and in Japan and other developed countries with a high quality of life and first-class medicine - over 80.
On the other hand, for many living things there is a certain maximum age, determined by the so-called Gompertz's law - upon reaching it, most of the animals die of old age, and the rest of the chances of dying the next year begin to grow exponentially.
In recent years, scientists have been actively arguing about whether this is typical for humans. In October 2016, American researchers showed that such a maximum age is possibly 100-115 years, which is rather modest by the standards of some biblical characters.
Wachter and his colleagues questioned these findings for the simple reason that the authors of the publications used data collected from surveys of older people themselves, many of whom, as scientists have suggested, tend to either overestimate or underestimate their age. Together with a small number of centenarians, this, according to Wachter, introduced many distortions in the statistics.
Therefore, Wachter's team took a different path - they used data that Italian social services collected among the country's oldest residents from 2009 to 2015. The biological age of all record holders, as the biologist emphasizes, was checked according to documents from the archives of all government agencies in Italy.
In total, three years ago, almost four thousand people over 105 years old and several tens of thousands of century old people and old women lived in Italy. The overwhelming majority of them are women - only 463 men managed to achieve this honorary mark.
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Observing how often centenarians died, scientists were surprised to find that the chances of not living until the next birthday remained the same - about 45-50 percent - when they reached 105 years.
This, in turn, means that Gompertz's law does not work for people - otherwise the probability of death of the oldest inhabitants of Italy would continue to grow, rather than stop at a fixed level. In other words, there is no limit to life.
Not all scientists agree with these findings. Brandon Milholland, one of the authors of the concept of the limit of human life, believes that even if the data of Wachter and his colleagues are correct, this does not necessarily mean that people can live indefinitely. In this case, the life limit will simply be significantly higher than the initial calculations showed.