Extra Life: A short history of living longer

[Chris_Falter]

@beaglelady

@Paraleptopecten

The biggest change is that child mortality rates are about a quarter of what they were 2000 years ago.

No. In the course of the past 100 years we have doubled our average lifespans with such things as vaccines, antibiotics, clean water, etc.

These are not necessarily contradictory. For example: Without vaccines centuries ago, many children died of diseases like measles and rubella, but others did not die and instead acquired long-term immunity. The effect of modern vaccines in reducing mortality would thus be seen primarily among children rather than among adults.

Best,
Chris

[beaglelady]

@Chris_Falter

These are not necessarily contradictory. For example: Without vaccines centuries ago, many children died of diseases like measles and rubella, but others did not die and instead acquired long-term immunity. The effect of modern vaccines in reducing mortality would thus be seen primarily among children rather than among adults.

But many more adults died of small pox, the 1918 flu pandemic, and the like.

[Chris_Falter]

Let’s see what the data say:

Secondly, let’s think about this mathematically. Suppose that a village has a population of 1000 and an average lifespan of 32 years. Suppose that over the course of a decade, 32 infants and 32 31-year-old adults die of smallpox. Looks like the distribution of deaths is equal over the period, so they should have an equal effect on the average lifespan, right? Hmm… not really.

The adult smallpox deaths decrease the average villagers’ lifespan by about 10 days. The infant smallpox deaths, by contrast, decrease the average lifespan by a full year. The infant deaths are outliers, which pull the average much lower than the deaths of adults who are closer to the average lifespan.

It’s kind of like Bill Gates and Jeff Bezos – 2 individuals – having a much larger effect on the average wealth and income of Americans than a small city has, but in the opposite direction (up instead of down).

Does that help?

Best,
Chris

[Paraleptopecten (Timothy Campbell)]

Yes, the life expectancy once you pass about 5 has gone up from about 45 for women and 60 for men to 75 for women and 70 for men (the larger change for women being primarily due to decreasing rates of death in childbirth).

[beaglelady]

@Chris_Falter

The effect of modern vaccines in reducing mortality would thus be seen primarily among children rather than among adults.

Covid-19? And did you even watch the program?

[beaglelady]

@Paraleptopecten

Yes, the life expectancy once you pass about 5 has gone up from about 45 for women and 60 for men to 75 for women and 70 for men (the larger change for women being primarily due to decreasing rates of death in childbirth).

What time span are we talking about?

[Paraleptopecten (Timothy Campbell)]

About the last 2000 years, again.

[Chris_Falter]

@beaglelady

Covid-19?

Sure, not every disease strikes hardest among infants and young children. But make no mistake, these are exceptions to the rule; the research is quite clear on this point.

The point is not that vaccines, antibiotics, and clean water have no effect on longevity. Instead, the point is that their beneficial effect on longevity has primarily operated through the reduction of child mortality. And I have already explained how the math works, which seems to have escaped your attention.

@beaglelady

And did you even watch the program?

I spent 5 years of my life as an administrator of a public health program that addressed maternal and child health in W. Africa. I had to familiarize myself with the research on both the historical and contemporary impact of disease and malnutrition on various sectors of the population as part of my job.

Have a blessed day.

Chris

EDIT: corrected typo in number of years I spent in W Africa

[jpm (Phil McCurdy)]

No doubt child mortality is a big factor. In days past, if you made it to adulthood, you had a pretty good chance of living to an old age. Antibiotics do seem to be a big factor in the old getter older, however, as they used to call pneumonia the “old man’s friend” as it often led to death, whereas now, you return to the nursing home. I would think medical advances tend to help the young and the very old where we humans are most vulnerable.

[beaglelady]

@jpm

No doubt child mortality is a big factor. In days past, if you made it to adulthood, you had a pretty good chance of living to an old age. Antibiotics do seem to be a big factor in the old getter older, however, as they used to call pneumonia the “old man’s friend” as it often led to death, whereas now, you return to the nursing home. I would think medical advances tend to help the young and the very old where we humans are most vulnerable.

Before antibiotics, as you know, people could die from a simple scratch that became infected.

Sanitation is an important factor in longevity also.

[paleomalacologist (David Campbell)]

The application to humans is highly controversial and raises serious ethical problems, but a wide range of animals live significantly longer if they are appreciably food-deprived without actually starving. There’s occasional speculation that some individuals may have lived a little longer than the modern record due to such factors, though the explanation on what shows as the fifth cartoon on this page must be considered as well: Science Cartoons Plus -- The Cartoons of S. Harris

[jpm (Phil McCurdy)]

Reminds me of the cartoon where the doctor comes out to talk to the family and says,“The bad news is, he didn’t make it. The good news is that I was able to to discuss the benefits of diet and exercise with him one more time.”