No Limit on How Long Humans Can Live, New Study Claims
While the average life expectancy for Americans currently stands at 78.7 years, results from a new study conducted by a team of researchers from Europe and the U.S. suggests that there's no limit on how long people can live.
In the study published Thursday in the journal, Science, researchers examined 3,836 Italians aged 105 and older between 2009 and 2015 and found that after age 105, the risk of dying remains the same.
"We observed level hazard curves, which were essentially constant beyond age 105. Our estimates are free from artifacts of aggregation that limited earlier studies and provide the best evidence to date for the existence of extreme-age mortality plateaus in humans," the researchers said in an abstract of their findings.
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Kenneth Wachter, a professor of statistics at the University of California, Berkeley, who is co-author of the study, explained to AFP that: "As we age, our health and risks of death get worse faster and faster. But at extreme ages, they stop getting worse. They don't get better, but they stop getting worse. They level out — it's called a plateau."
The study also looked at mortality among people born in the same years and found that over time they found slight declines in the mortality rate, suggesting that people are living longer than others born in prior years as time goes on.
"The slow but distinct improvements over time that we see in the level of the plateau beyond age 105 give hope that a fixed limit to life span is not currently in view," Wachter said.
Not all researchers, however, see the results of this study as evidence that there isn't a limit to the human life span. Brandon Milholland, who co-authored a paper published in Nature in 2016 which argues that human life is bound by the limits of natural processes, told Live Science that he wasn't convince the study pointed to evidence of a plateau.
"I do not consider the evidence for a plateau presented in this paper to be especially strong," Milholland said, noting that "if we assume that this paper is correct and mortality [risk] is flat after age 105, the fact that the chances of dying don't go up doesn't mean there is no limit to life span."
He further noted that: "There aren't many 105- year-olds to begin with, and only a fraction of them will live to 106. And only a fraction of those survivors will make it to 107, and so on. Soon, we reach an age at which we expect close to no survivors, or a survivor only once in 1,000 or 10,000 years."
For Christian perspectives on how long people can live, the website Got Questions says:
Many people understand Genesis 6:3 to be a 120-year age limit on humanity, "Then the LORD said, 'My Spirit will not contend with man forever, for he is mortal; his days will be a hundred and twenty years.'" However, Genesis chapter 11 records several people living past the age of 120. As a result, some interpret Genesis 6:3 to mean that, as a general rule, people will no longer live past 120 years of age. After the flood, the life spans began to shrink dramatically (compare Genesis 5 with Genesis 11) and eventually shrank to below 120 (Genesis 11:24). Since that time, very few people have lived past 120 years old.
However, another interpretation, which seems to be more in keeping with the context, is that Genesis 6:3 is God's declaration that the flood would occur 120 years from His pronouncement. Humanity's days being ended is a reference to humanity itself being destroyed in the flood.
Some dispute this interpretation due to the fact that God commanded Noah to build the ark when Noah was 500 years old in Genesis 5:32 and Noah was 600 years old when the flood came (Genesis 7:6); only giving 100 years of time, not 120 years. However, the timing of God's pronouncement of Genesis 6:3 is not given. Further, Genesis 5:32 is not the time that God commanded Noah to build the Ark, but rather the age Noah was when he became the father of his three sons. It is perfectly plausible that God determined the flood to occur in 120 years and then waited several years before He commanded Noah to build the ark. Whatever the case, the 100 years between Genesis 5:32 and 7:6in no way contradicts the 120 years mentioned in Genesis 6:3.
Wachter told Live Science that genetics and "frailty" selection could contribute to the existence of plateaus.
He explained frailty selection using the example of walking into a 50th college reunion.
"Some people look to be in the peak of health and are bragging about climbing mountains and other people are not doing so well, they're frail," Wachter said.
In 25 years, most of the frail people don't show up to their 75th reunion because they will have died at higher rates, he said, because "the people who do show up 25 years later ... are the people who were stronger and more robust earlier on."
