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Adventures in extreme aging

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Today marks the 119th birthday of Kane Tanaka, who is the third person to ever officially achieve that milestone.

Here are a few statistical curiosities about the history of extreme aging:

(Everything below needs to be understood in the context of the fact that anything like even vaguely comprehensive public health records didn’t exist anywhere until the late 19th century, and still don’t exist in much of the world, so obviously there are huge gaps in the historical record)

(1) Prior to 1955, there was no accepted historical case of any person having reached a 113th birthday.

(2) Prior to 1984, there was no record of any person having reached a 114th birthday.

(3) Since then, many hundreds of people have reached the age of 113, about 175 have reached the age of 114, 58 have reached the age of 115, 24 have reached the age of 116, ten have reached the age of 117, three have reached the age of 118 (a woman in France is a little more than a month away from becoming the fourth), the same three reached their 119th birthday, and one person has reached the age of 122.

(4) Annual mortality risk for humans increases more or less exponentially until about the age of 80, and then begins to flatten out. It appears to pretty much plateau at around age 105 at about .5 (meaning half of any age cohort at that point can be expected to die in the following year). If it really does plateau, this would mean there would be no statistical barrier per se to anyone reaching any age, although of course the odds of doing so would be basically infinitesimal at much past 120, based on current demographics.

(5) Women on average live around 9% longer than men, so naturally this survival advantage becomes ever-more pronounced at statistical extremes. Hence 55 of the 58 people to reach the age of 115 have been women, including all of the 20 oldest people in recorded history.

(6) The national distribution of the oldest people is totally dominated by the developed world, and in particular two countries: the USA and Japan. Of the 100 oldest people ever, 35 have been Americans, and 29 have been Japanese. The latter total is more than two and a half times larger than the former on a per capita basis. In fact it’s such an extreme figure that I wonder about its reliability, especially given that the rest of Asia, Africa, and the Middle East — collectively home to more than three quarters of the world’s entire population — have to this point produced between them exactly zero of the world’s 100 verified oldest people (Note again the caveat about public records being an issue in this regard however).

What factors have produced such a striking extension of the maximum human lifespan in the past 35 years or so? Note that one factor which is pretty minor in this regard is the increase in the world’s population. While the world’s population exploded in the 20th century, that in and of itself is almost irrelevant to this particular question. The 100 oldest people were all born between 1871 and 1907, and the world’s population only increased by about 25% over that span.

A factor that has surely played a major role is medical care for the elderly. Even looking at much more ordinary lifespans — people living into their 80s and 90s — mortality rates in those cohorts have dropped a great deal in the USA since the middle of the 20th century. For example, between the middle of the 20th century and 2019, annual mortality rates among people 85 and over fell by almost half, from about 22 per 100 to 13 per 100. (While gains in life expectancy in the USA in the first half of the 20th century were largely driven by declining infant and childhood mortality rates, since then they have been more strongly affected by declining mortality in the middle-aged and elderly). And although I don’t have the data, I would expect to see a similar pattern in the rest of the world, or at least the developed world.

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