Once you hit this age, aging appears to stop

You can halt aging without punishing diets or costly drugs. You just have to wait until you’re 105. The odds of dying stop rising in people who are very old, according to a new study that also suggests we haven’t yet hit the limit of human longevity.

The work shows “a very plausible pattern with very good data,” says demographer Joop de Beer of the Netherlands Interdisciplinary Demographic Institute in The Hague, who wasn’t connected to the research. But biodemographer Leonid Gavrilov of the University of Chicago in Illinois says he has doubts about the quality of the data.

As we get older, our risk of dying soars. At age 50, for example, your risk of kicking the bucket within the next year is more than three times higher than when you’re 30. As we head into our 60s and 70s, our chances of dying double about every 8 years. And if you’re lucky enough to hit 100 years, your odds of making it to your next birthday are only about 60%.

But there may be a respite, according to research on lab animals such as fruit flies and nematodes. Many of these organisms show so-called mortality plateaus, in which their chances of death no longer go up after a certain age. It’s been hard to show the same thing in humans, in part because of the difficulty of obtaining acccurate data on the oldest people.

So, in the new study, demographer Elisabetta Barbi of the Sapienza University of Rome and colleagues turned to a database compiled by the Italian National Institute of Statistics. It includes every person in the country who was at least 105 years old between the years 2009 and 2015—a total of 3836 people. Because Italian municipalities keep careful records on their residents, researchers at the institute could verify the individuals’ ages. “These are the cleanest data yet,” says study co-author Kenneth Wachter, a demographer and statistician at the University of California, Berkeley.

The risk of dying leveled off in people 105 and older, the team reports online today in Science. That means a 106-year-old has the same probability of living to 107 as a 111-year-old does of living to 112. Furthermore, when the researchers broke down the data by the subjects’ year of birth, they noticed that over time, more people appear to be reaching age 105.

“[That’s] strong evidence that if there is a maximum limit to human lifespan, we are not close to it yet,” Wachter says. But what that maximum is—the current longevity record is 122—remains to be seen, De Beer cautions.

The plateau may occur because frailer people gradually die off, leaving only the toughest alive. Many factors, including genes, likely account for their hardiness, and identifying these factors may suggest ways to boost survival in younger people.

Wachter says he hopes the paper will resolve the debate over whether there is a mortality plateau in humans. But Gavrilov says the authors haven’t reassured him that the longevity data is as clean as they claim. For instance, he wants to know more about the people who didn’t make it into the database because their reported ages couldn’t be confirmed and whether excluding them affected the results. “This paper will not settle the debate, but will ignite it further,” he says.