Map of life expectancy at birth from Global Education Project.

Tuesday, April 27, 2021

Well, Stayin' Alive

Steven Johnson has written the book I've been meaning to write, about the history of human life expectancy. (Don't worry, I've got another project in the works.) I'm not sure how the paywall works with the NYT magazine, but he provides a great overview here, which I hope you can read. 


As I've discussed here more than a few times, life expectancy bounced around just a little from time to time and place to place from the neolithic until the late 19th Century. Then it doubled, quite suddenly, first in the wealthy countries and then around the world. It's an artificial construct and interpreting it isn't straightforward, but to put it in a pistachio shell the most important difference is infant mortality. In the old days, a whole lot of babies and young children died. So while life expectancy was around 40 years give or take, if you got past the age of 5 or so, you could hope for your three score years and ten, although not with as much expectation as we enjoy today. Women still died in large numbers in childbirth, people died of infections subsequent to minor injuries, and they died of viral diseases, notably smallpox. 


This has been the most dramatic change in the human condition ever. Sure, fire was nice and iron tools, and while agriculture may not have made us better off on the whole it certainly changed things. But the idea that it's normal for children to survive and the typical person in many countries lives to be at least 80 is mind boggling, if you allow yourself to think about it long enough to get boggled.

 

As Johnson explains, scientific advances of the late 19th and early to mid 20th Century had a lot to do with what amounted to a transition of the human species into a different universe, but by itself scientific understanding of mortality wouldn't have made much difference. Pasteur figured out how to kill pathogens in milk, but it didn't start saving millions of children's lives until laws were passed that made it mandatory. Milk producers refused to do it voluntarily. It required a substantial public investment to deliver clean drinking water to cities, which was the other biggie. Smallpox vaccination existed since 1796, but it took a massive, coordinated global effort to eradicate the scourge from the earth in 1979. It took more than 10 years from Fleming's discovery of penicillin before it became possible to produce it on a large enough scale to matter, and again that took a large public investment -- specifically by the U.S. government during WWII. Most medications were completely useless until the FDA began to require manufacturers to prove their safety and efficacy in randomized controlled trials.


I could go on but these are the highlights. Public health is a public responsibility.

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