Correction on Life Expectancy

Bird Dog writes me with a correction to my statement that even the poorest today enjoy much longer life spans than folks 100 years ago.  He writes:

In the past, average life span was short, due to infant and childhood
mortality, and young adult mortality, due to infectious disease. It's a
statistical error, really.
 
There was a bi-modal mortality, peaking in the early teens, and again
in old age. Infant mortality was high.  That youth mortality has been
eliminated by antibiotics, so we no longer have a bimodal mortality graph. But
that youth mortality falsifies the historical averages, giving the
appearance of a lower life span than today..

That is a valid point.  Of course, the much longer average life span has meaning, just not in the exact way I implied.  In a previous article, I formulated this difference more carefully, and in a way I think is consistent with Bird Dog's observation:

1)  A hundred years ago, you would have been more likely, by an order of magnitude, to see at least one of your kids die.  Even in my father's generation (born in 1922) it is unusual to find anyone who did not lose a brother or sister young, as both my mom and my dad did.

2)  Many people from centuries past lived as long as we today might expect.  Thomas Jefferson, George Washington, and John Adams all lived to ages we would even today call "old".  However, I would venture that most of these folks' lives in their last ten or twenty years was of much lower quality than our lives at these ages today.  We may not live much longer, but our last 10-20 years are much more enjoyable.  My father-in-law was biking and white-water kayaking in his seventies right up to his untimely death in a car accident.  Among other things, teeth, eyes, and joints are all body parts that tend to fail in a non-terminal manner.  We can fix many of the age-induced problems with these parts, and while it may not extend life, it sure as hell extends living.

  • Sol

    I think you should stick to your guns here. It's certainly true that infant mortality drags down the average life span historically, and there were people then who lived as long as the longest-lived people today. But those facts shouldn't disguise the point that an adult was still much more likely to die prematurely back then.

    To pick a particularly bad year -- the 1918 flu epidemic killed 0.6% of the US population. But early death from disease wasn't that unusual -- I remember reading about one mid-19th century year when half of the still smallish University of Michigan class died.

    Ever wonder why dying in childbirth is so common in older fiction, but rarely shows up in modern life? In 1900, 1 in 100 live births saw the mother die. Today that number is 1 in 10,000 -- and of course, women tended to have quite a few more kids back then. Back then, your average American woman had a 5-10% chance of dying in childbirth, versus something like a 0.015% chance today.

  • bruhaha

    No, the correction is well-taken. How often have I heard people use the "life-expectancy" numbers suggested for ancient Rome, Israel, etc. to draw the picture of societies within which practically NO ONE made it much past 40 ?! Not hardly!

    None of this is taken anything away from the wonderful medical advances at BOTH ends of life -- in reducing deaths of minors (not just infant mortality) and vastly improving the health and quality-of-life for so many elderly.

    Minor corrections on the examples listed -- Washington died at the age of 67 (in 1799), not quite ancient, and his health was actually quite good till very near the end. He died of the sort of infection he was prone to (similar, I believe, to the one he almost died of in the late winter of 1777,when he was 45 and generally in excellent health).

  • Sol

    I'm assuming the quote we are talking about is "Today, even people below the poverty line have a good chance to live past 70." I guess you can quibble about how you want to define "a good chance", but it is certainly true that a 10-year-old in 1950 has a drastically better chance of being alive in three years than a 10-year-old in 1850 had of living to 1910 -- and that represents a real and very substantial improvement in the lot of the poor. (And everyone else too!)

  • http://maggiesfarm.anotherdotcom.com/ bird dog

    Antibiotics are the key. Women died in childbirth (including my grandmother) from puerperal fever, back when docs didn't wash their hands between cases.

    Coyote has a good point: A 70 year-old today is not the same person as a 70 year-old two generations ago. My parents played tennis into their 80s, when their parents would have been sitting in chairs.

  • Sol

    I found stats: http://www.infoplease.com/ipa/A0005140.html

    (I'm giving expected total years of life, not years left to go.)

    1850 White male aged 10, expected age at death: 58
    1950 White male aged 10, expected age at death: 69
    1850 White female aged 10, expected age at death: 57
    1950 White female aged 10, expected age at death: 74

    The rate is predicted to keep going up; the expected life spans for people 10 years old in 2004 is 76 for white men and 81 for white women. (And the improvement over time is even greater for non-whites.)

  • dearieme

    When the "Old Age Pension" was introduced in Britain shortly before WWI, the pension age was fixed at 70 because (i) few people reached that age, and (ii) they would find it hard to earn a living when they did. Later, vote-buying reduced the age to 65, and then to 60 for women. Now it is being returned to 65 for women, and then it will increase to 68 for both sexes. Whether Britain will still exist in the year when the age is meant to reach 68 is an open question. Or the USA, for that matter.

  • JLBurns

    Having been intimately involved with the issues relating to pension funding (painfully so), I can assure you that the anticipated life expectancy of "older" people has increased substantially. In the last 20 years, the anticipated life expectancy of a 65 year old in the UK has gone from approximately 15 years (average life expectancy of 80) to approximately 19 years (average life expectancy of 84) and continues increase. The impact on pension schemes is dramatic -- that 4 year increase is a 26% increase in the length of time an individual is going to receive a pension.

    So, while it may be true that a substantial part of the increase in "average life expectancy" is due to decreases in mortality in the early years of life, the life expectancy of those in retirement age is also increasing. And those increases in life expectancy have a dramatic impact on the funding requirements for retirement benefits of all types.