Why a decline in mortality rates among very old people may be ‘an illusion’

An intriguing phenomenon has emerged in recent years: among very old people, the rate at which people die appears to decline when they get past a certain age.

…

Not so fast, says a new study by Saul Newman in PLoS Biology. Newman looked at the data and found something quite different: it’s all just a mistake.

…

[W]e don’t have very good birth records for people over 100 years old. They were born a long time ago, when record keeping wasn’t always so good. What if there are a few errors?

…

[L]et’s imagine a set of people whose true ages are off by 5 years in either direction. (I know that’s a lot, but bear with me.) By the age of 100, as Newman points out, virtually no one is alive from the cohort that underestimated their age; these are people who have a true age of 105. But many more will be alive from those who overestimated their age; these are the 95-year-olds who think they’re 100.

Newman’s paper points out that if only a few people are overestimating their age, this can cause mortality rates to flatten or decelerate–or at least they appear to decelerate, because these people aren’t really as old as we (or they) think they are.

…

In other words, the decline in mortality is simply an illusion.

Read full, original post: What’s the limit of the human lifespan? And what do World War I veterans have to do with it?