Menopause and life expectancy

The menopause column raised an issue I’ve long wondered about but haven’t seen it directly addressed. Cecil said:

“Average age at menopause today is 51; average life expectancy in 1900 had only reached 47. In other words, during most of evolutionary history, the average woman had enough eggs to last a lifetime.”

Now, what I’m wondering is did Cecil mean “average life expectancy assuming one made it to adulthood” when he said “average life expectancy”? Because my understanding is that one of the reasons life expectancy was so low a hundred years ago compared to today is because the infant and child mortality rate was so high, relatively. This means that when you hear that in 1900 the average life expectancy was 47, it doesn’t mean that people who made it past childhood would reach 47 and drop dead, on average. If they made it to adulthood, they would likely live well beyond 47, though admittedly not to the advanced ages we reach today.

So, it seems to me that the fact that the age menopause generally starts and the average life expectancy 100 years ago are similar doesn’t really mean much, since in reality women who reached adulthood in 1900 would surely live longer than 47 on average.

Now, I will admit that it seems probably true that the average life expectancy assuming one made it to adulthood may have been around 50 “during most of evolutionary history,” as Cecil said, but my post really isn’t arguing about this menopause theory, it’s really wanting to address this often misunderstood notion of average life expectancy.

This is an issue I’ve long thought about because I’ve heard people at social gatherings say things like, “Wow! You’re 35? 1000 years ago you would have been dead!” Well, no. Average life expectancy may have been in the early 30s back then, but again, it doesn’t mean people who reached that age also died around that age on average. Yes the age people died on average assuming they made it to adulthood was much lower way back then, but it was certainly older than the early 30s.

– Matt

Cecil talks about the average age of menopause today, in relation to the average life expectancy in 1900. He does consider whether the average of menopause may have moved up or down in the past 100 years.

I agree - Cecil has it all wrong. The myth of people dying off at 40 years old hundreds and thousands of years ago is totally wrong.

Adult human lifespan is not radically changed over the last few hundred years - back in the 1800’s, people routinely lived in their 70s and 80s. The dramatic change in lifespan is primarly due to infant/childhood mortality decreases due to things like vaccinations.
I hate when I read stuff like this - especially from a guy like Cecil.:wally :wally

He made another boo-boo in the line

Generally, in the 19th century and before, kids reached puberty around age 15 or 16. It’s only been in the past century that this age has crept down to 11 or less. There’s been lots of arguements about why, but I believe the evidence is in favor of improvements in nutrition.

Anyway, these errors don’t really detract from his thesis, but rather cancel each other out. Menopause happens around age 50, and average life expectancy of women who reached adulthood was around 65 up 'til recent times. Thus his conclusion

is correct.

Amazing. The first time I went to make a comment on a column I see that “dogcone” has stolen my thunder. This canard about life expectancies in days gone by is something that has bugged me for decades. And here I see Cecil repeating it. Using the logi that leads to the canard would lead one to say that the life expectancy in the Irish slums of Boston in 1850 was 12 or 13, which was the average age of the corpses being buried (or at least so I read somewhere).

An associated misspeak is of the form “She was born in 1845 and lived to 60, old age back then.” Etc.

Cecil’s basic problem is the age-old one of confusing the median/average with the mode.

Even if the average life expectancy of a woman in 1900 was 47 doesn’t mean that most, or even a large percentage of women died around age 50.

For example, suppose half of women died at age 30, and the other half died at age 70. You’d still have an average life expectancy of 50 … but, in fact, nobody would die at the average life expectancy. And fully half of the female population would go through menopause.

dogcone: The average life expectancy at birth in 1900 was 47 (and that’s for males, not females … Cecil really was napping on this one). See:

http://www.pbs.org/fmc/timeline/dmortality.htm

The average life expectancy at adulthood (say, age 10 or 15 or 20) in 1900 was presumably much larger, since it excludes infant and child mortality. I can’t find a cite for 1900 life expectancy at adulthood, though.

Some figures I found: " In 1900, a 20-year-old had only a 52 percent chance of surviving to age 65. . . In 1900, only 4 percent of Americans were 65 or older. Today, fully 13 percent of Americans are 65 and older."

http://www.difficultdialogues.com/DD1/consensus_report/cr_01.html

Hasn’t Walloon put his finger on it? I imagine that Cecil knows the difference between lifespan and life expectancy, but for the purposes of his column, isn’t the important point that there would be no evolutionary advantage to selecting for grandmothers, since there would be so few grandmothers around? How may post-menopausal women have been discovered at Cro Magnon or homo erectus sites?

Rube, evolution does not award evolutionary changes solely to the largest sub-group in a species. It’s more a much more hit-and-miss process. I’m sure the biologists out there can think of all sorts of adaptations that affect only a small percentage of a species population. (E.g. queens in ant colonies are only a tiny proportion of the total ant population, but it does not follow that evolution never affects the queens.)

Keeping the queen analogy in mind, it may make sense to use menopause to increase the tiny percentage of surviving oldsters around, if the oldsters are disproportionately useful to the species for some reason (raising kids, remembering where the good water holes are, etc.)

I can’t believe we’ve made it this far into the thread without posting a link to the original article:

And before anyone nitpicks me: I made it sound like the median and the average are the same thing, and of course they’re not. :slight_smile:

Found some better dope on the age distribution in 1900:

Fully 44% of the population in 1900 was under the age of 20.

I think Cecil (and everybody else) missed the point.

He was so busy going down a detour that he may have forgot the original question.

The question was: Why do women go into menopause and men don’t?

the answer has to do with with what menopause is:

It is a change in hormone levels. this change happens when a woman runs out of ovum (eggs).

Joseph W. Baric Jr, that only leads to another question: Why do women run out of ova when at around 50, when about a third of their life is still ahead of them? That’s what Cecil was addressing.

You’re right, that’s the real question.

And again, he never addressed that.

I don’t have an answer for the question, though I am curious about his statement that only humans go through menopause. I doubt there are geriozoologists around telling us what happens when all mammals get older, but I would be surprised if that is unique to us.

And even if we are unique in that, I would be curious to see if we are also the only species that has a finite number of ovum.

[[But for now it appears menopause doesn’t mark your graduation to some higher stage of nurturing; it just means you’ve gotten old.]]

I note that Cecil did not consult his perimenopausal assistant while researching this column. I also suspect that in a push-up/arm wrestling/running contest with many girlish 20s-30something types, I’d win.

Jill
Though I agree I haven’t gotten any more nurturing.

Perimenopause? Pah. Sounds to me like somebody somewhere had friends going through real menopause, and she just wanted to jump on the bandwagon and proclaim, “Me too!” 'cause she didn’t have enough problems of her own to whine about. Hmph!

This is in response to JillGat

You state that you would win in a feat of strength against a younger woman.

I’m just curious. I would think that loss of calcium (due to aging) and also atrophy of muscles would occur by that time. In fact, I thought that one of the dangers of menopause was osteoporosis.

do you lift weights, or is what little I read on the subject in error?

Well, sort of. Cecil has already discussed this in a previous column: Does use of The Pill delay menopause? in which he says

Thank you dtilque for the correction.

I didn’t mean to start a whole new thread. my whole point was that Cecil had not answered the question asked. he just belittled a simplified explanation - he didn’t give any different ones.

I will read that straight dope essay.

“The increase in life expectancy occurred as a result of prevention and treatment of conditions which used to cause large numbers of younger people to die prematurely”

http://www.seniorworld.com/articles/a20000423200331.html

I run and lift weights and have done so for years. It takes a little more work to stay in shape as you age, but I’m in about as good a shape now as I was in my 20s. And I’m just as immature.

re. “perimenopause,” if I wasn’t taking hormones, I’d be having hot flashes and other symptoms of early menopause. I think perimenopause is the correct term, but I’m not sure. I’ll be 48 in a couple of weeks. I thought menopause was when the periods stopped for good.