[ad_1]
From 1900 to here, life expectancy more than doubled across the planet. "If there is a fixed biological limit, we are not close to it," says Elisabetta Barbi, a demographer at the University of Rome. "If a fixed biological limit exists, we are not close to it," said Elisabetta Barbi. Barbi and his colleagues published the results of their research in the journal Science
The current record of human longevity was established 21 years ago when the French Jeanne Calment died at the age of 122 years. Nobody up to now has gone beyond the age that she has reached – at least as far as the scientists know it.
In 2016, a team of scientists from the Albert Einstein College of Medicine in the Bronx stated that the age reached by Calment was even more out of the norm than it was there. appeared. They argued that humans had reached a fixed longevity limit, which they estimated at 115 years old.
Several critics have attacked the research. "The dataset was very precarious and the statistics were incorrect," said Siegfried Hekimi, a biologist at McGill University
Anyone who studies the limits of longevity faces two major challenges statistics: few very old people and people who live so often forget how old they are.
Barbi and his colleagues went through the Italian birth registers to identify all citizens who had reached the age of 105 between 2009 and 2015. To validate the ages, they located the birth certificates.
The team ended with a database containing the names of 3,386 long-lived Italians. The researchers located the death certificates of the deceased throughout the study period and calculated the percentage of deaths in each age group.
It has long been known that the percentage of deaths in each age group starts falls
If the percentage of deaths continues to increase exponentially in people who reach advanced age there would be the possibility that human life had an age limit of about 115 years.
But that's not what Barbi and his colleagues have determined. Among the extremely elderly Italians, the percentage of deaths ceases to increase – the curve flattened abruptly and reached a plateau.
The researchers also found that, over time, the death rate of people has become lower. when they reached 105, compared to previous centenarians.
"The mortality curve has been relaxed over time," said Kenneth Wachter of the University of California at Berkeley, who co-authored the new study. "The improvement in mortality extends to extreme ages, and we are not yet approaching any maximum duration for human life."
New research does not explain why the death rate is steadily increasing in the elderly.
The possibility is that some people have genes that make them more fragile than others, leaving behind a group of very resistant older people.
But Hekimi speculated that there could be other factors at play. Throughout our lives, our cells are damaged. We managed to partially repair them and, over time, our body was weakened.
It is possible that at the cellular level, very old people simply live at a slower pace. As a result, they accumulate less damage to their cells than their bodies are able to repair.
The fact that the death rate ceases to increase does not mean that centenarians have found the fountain of youth. From one year to the next, they are even more likely to die than people in their 90s.
How much longer centenarians will live can be determined by chance each year.
Source link
