When it comes to milestone birthdays ages 18, 21, 40, 50, 75 and 100 seem to get all the glory, but now a Stanford-led study suggests that reaching the age 65 is cause for extra celebration.
Stanford biologist Shripad Tuljapurkar, PhD, and a team of Stanford researchers found that people over the age of 65 in developed countries will live, on average, about six years more than their grandparents did.
This result was not expected.
Tuljapurkar and his colleagues were curious to know whether people are approaching a limit to human lifespans, and if so, are there factors that enable some people to live longer than others.
To find out, they examined a 50-year dataset of birth and death records. These longevity records included people living in 20 different developed countries between 1960 to 2010.
Tuljapurkar suspected that humans were approaching the upper bound of their lifespan, but the data revealed a different scenario. Tuljapurkar explained the findings of their study in a recent Stanford news story saying:
The data shows that we can expect longer lives and there’s no sign of a slowdown in this trend. There’s not a limit to life that we can see, so what we can say for sure is that it’s not close enough that we can see the effect.
The results showed that the average death date for people living beyond the age of 65 increased by three years in every 25-year period. As the researchers write in their paper, this trend is noteworthy because of its "surprising regularity."
One might think that a certain decade would be unusually good or bad for survival, or that particular medical advancements had a big effect on human longevity.
Instead, the trend of increased lifespan is consistent across all decades in the study, for males and females, in all 20 countries, and there was no significant increase in longevity from any particular medical breakthrough.
So, what's helping people over the age of 65 live longer?
According to this study, it's not yet clear. No single biological factor was found that seemed to give certain people the ability to live longer than others. Even wealth didn't seem to confer a significant survival benefit — at least not for people over the age of 65.
"As someone who would like to be a one-percenter but is not," Tuljapurkar quipped, "I’m certainly very happy to know that my odds of getting to live longer are just as good as the millionaire down the street.”
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