How long can humans live? A new study published October 5 in the journal Nature suggests that the human life span has a hard ceiling of around 115.
The result might at first appear counterintuitive, since human life spans have generally been going up over the last century in most countries. For example, an American born in 1900 could expect to live to approximately 50; today's kids should have an average life span of 79. However, the number of extraordinarily old people appears to be leveling off.
Study authors Xiao Dong, Brandon Milholland and Jan Vijg from Albert Einstein College of Medicine looked at records of longevity in countries around the world. The team found that the maximum age of death in the United States, United Kingdom, France and Japan (countries which have the largest numbers of supercentenarians—individuals aged 110 years old or more) reached a peak of just under 115 in 1995, and that figure has actually declined slightly since then. Their calculations suggest that there is only about a one in 10,000 chance of somebody living beyond the age of 125 in any given year.
The study is the latest salvo in what is a relatively controversial field. Some researchers said the results were logical. Jay Olshansky, from the University of Illinois, told the BBC that it looks like humanity is indeed "approaching a natural limit to life."
However, James W. Vaupel, the director of the Max-Planck Odense Center on the Biodemography of Aging, said the paper was a "travesty." "It is disheartening how many times the same mistake can be made in science and published in respectable journals," Vaupel told The New York Times. He argues that the authors didn't properly account for the fact that the fastest-growing group of people continues to shift toward an older age, and didn't use the most accurate statistical models.
The world's oldest person ever, a French woman named Jeanne Louise Calment, lived to the age of 122.
