<body><script type="text/javascript"> function setAttributeOnload(object, attribute, val) { if(window.addEventListener) { window.addEventListener('load', function(){ object[attribute] = val; }, false); } else { window.attachEvent('onload', function(){ object[attribute] = val; }); } } </script> <div id="navbar-iframe-container"></div> <script type="text/javascript" src="https://apis.google.com/js/plusone.js"></script> <script type="text/javascript"> gapi.load("gapi.iframes:gapi.iframes.style.bubble", function() { if (gapi.iframes && gapi.iframes.getContext) { gapi.iframes.getContext().openChild({ url: 'https://www.blogger.com/navbar.g?targetBlogID\07518872353\46blogName\75The+Lactivist+Breastfeeding+Blog\46publishMode\75PUBLISH_MODE_BLOGSPOT\46navbarType\75TAN\46layoutType\75CLASSIC\46searchRoot\75http://thelactivist.blogspot.com/search\46blogLocale\75en_US\46v\0752\46homepageUrl\75http://thelactivist.blogspot.com/\46vt\0754224927842028678352', where: document.getElementById("navbar-iframe-container"), id: "navbar-iframe" }); } }); </script>

Myth Busting - Average Age of Weaning 4.5 Years

Looking for The Lactivist? She's retired. But you CAN still find Jen blogging. These days, she's runs A Flexible Life. Join her for life, recipes, projects and the occasional rant.

Monday, January 07, 2008

Since I've already been accused (again) of being mean this week, let's also gear up to get me accused of being anti-breastfeeding. ;) (For you new readers, that's called me having a sense of humor. It in no way means I am mean or anti-breastfeeding. I can't speak to the former, but the latter couldn't be further from the truth.)

Moving on...

My friend Anna and I have both found ourselves in discussions recently where someone pulled out that old "well the average age of weaning world-wide is 4.5 years" stat when the subject of weaning came up.

I've heard this one bandied about myself several times, including once or twice during the recent weaner-gate fiasco. To be honest, this "stat" has always really bothered me. Not because I don't think mothers should nurse for as long as they and their children desire (I do), but because this stat gets used as a "you're a bad mother" stat for moms who choose to wean prior to age two (or at all, really.)

For your average American mother who chooses to breastfeed for whatever reason, but does not choose to arm herself to the teeth with stats and studies, or who does not hang out with mothers who practice extended or child-led weaning, this stat sounds crazy.

Here's why.

It says the AVERAGE age of weaning is 4.5.

Let's get a reminder of what average means. To get the average age of weaning, you would add up the ages of every child who naturally weaned and then divide that number by the number of children tallied. The average is the result of that division. For every child who falls BELOW 4.5, there has to be a child who lands ABOVE 4.5.

Now, take a moment and think of the conversations you've had with women who allow their children to wean on their own. If I think of my own friends and acquaintances (online, few folks I know offline nursed at all, let alone let their kids wean at their own pace) most kids stopped nursing sometime between 10 months and 3 years. I can think of a *few* instances where the child nursed until 4, but only one or two where someone nursed past 4.5.

Now, for every one of those children who self-weaned prior to age 4.5, there has to be a child who went an equal amount PAST 4.5.

In other words, there'd have to be a TON of nursing 6, 7, 8 and even 9 year olds running around in the world. In fact, there'd have to be an equal number of them as there are children who wean prior to age 4.

Anyone out there believe that to be true? Anyone?

Yeah, me neither. Which makes that stat sound like a total made up piece of crap to a mainstream mother who is weaning her child at 10, 12, 18 or even 24 months. It also makes the person spouting it look like they have an agenda. (Which they do, and that's ok, but when that agenda makes you lose credibility, it's not good.)

Now, I'm not a fan of using anecdotal knowledge to try and push back on "FACT." (See it done all the time with birthing and it drives me nuts.) So, I wanted to find out what the source of this stat was thinking *maybe* there are enough countries with longer nursing periods going on to actually make up that difference.

There's not.

Neither Anna nor myself knew where this stat came from and when we questioned the people throwing the stat around, we didn't get an answer from them either.

That number is totally, 100% made up.

In fact, I ran across a link today to Katherine Dettwyler's "A Natural Age of Weaning" article. This is the article that the 4.5 number seems to come from, which is funny because even Katherine Dettwyler says the number is "made up."

One often hears that the worldwide average age of weaning is 4.2 years, but this figure is neither accurate nor meaningful. A survey of 64 "traditional" studies done prior to the 1940s showed a median duration of breastfeeding of about 2.8 years, but with some societies breastfeeding for much shorter, and some for much longer. It is meaningless, statistically, to speak of an average age of weaning worldwide, as so many children never nurse at all, or their mothers give up in the first few days, or at six weeks when they go back to work. It is true that there are still many societies in the world where children are routinely breastfed until the age of four or five years or older, and even in the United States, some children are nursed for this long and longer. In societies where children are allowed to nurse "as long as they want" they usually self-wean, with no arguments or emotional trauma, between 3 and 4 years of age.

Dettwyler goes on to explain that she (and others) have spent a ton of time researching the weaning ages of animals (who don't have cultural matters weighing in on weaning decisions) and speculating on what the biological weaning age of children *might* be. They looked at issues like length of gestation verses length of breastfeeding, time it takes to double or triple weight verses length of breastfeeding, even introduction of molars to the length of breastfeeding.

Using those criteria, they decided that the "natural" age of weaning for humans was probably somewhere between 2.5 and 7 years of age.

While that's very interesting information, it's also a pretty big window.

Best I can figure, someone decided to split the difference, arrive at 4.5 and start touting it as a "fact." People heard it, believed it and passed it on.

Now, leaving apart the question of whether or not looking at how long other species nurse has anything to do with how long humans nurse, the reality is this is a completely made up fact that does nothing to promote the benefits of long-term nursing.

We do not help our cause when we "rely" on made up facts. Personally, I'd love to see this stat get tossed out the window and for more women to focus on the myriad of stats we DO have to promote breastfeeding and extended breastfeeding.

Incidentally, if you didn't follow the above link to read Dettwyler's piece, I'd strongly encourage you to give it a read. It's quite interesting on many levels, but also brings up a very important point. Dettwyler points out how few studies actually distinguish the benefits of nursing beyond the age of two. In other words, in studies of the impact of long-term breastfeeding, everyone who nurses longer than two years gets lumped in together. Prior to the age of two, things tend to get broken down into blocks of 1, 3 or 6 months.

Wouldn't it be great to see some REAL data come out that actually looks at the difference between nursing to three years as opposed to two? Or to three and a half as opposed to three? And so on? To really break things down into smaller chunks? A study that examines the composition of milk beyond that second year to find out how the immunities change and what other properties of the milk might change?

Personally, I think it would be interesting information. In terms of the breastfeeding movement, I think it would give CLD and extended nursers some GREAT, factual information they could use to educate nay-sayers about their choices.

To moms who have thrown out that number as a "fact," I'd encourage you to let it go, or at least to clarify how the number came about. To other moms who have had it used against them, here's your info to refute the claim.

And once again, this post is NOT about discrediting breastfeeding or giving reasons why moms should NOT nurse for as long as they wish. It's about promoting the FACTS and not the fiction.

Labels: ,

  1. Blogger Lesley | 8:40 AM |  

    I had always wondered about that statistic...thank you for pointing me into the direction of the research.

    I truly hope others will read this and see it as a well-researched post, that you aren't just throwing out insults against child-led weaning.

    Once again I lament the fact that as a group we can't seem to stop the in-fighting and band together for our common goal. Does no one else see that when we attack one another we play right into the hands of those who would put breastfeeding down?

  2. Blogger Maria | 9:09 AM |  

    Not to nitpick, but...

    "For every child who falls BELOW 4.5, there has to be a child who lands ABOVE 4.5."

    That is only true if you are using the median.

    Your description of adding up the age of weaning and dividing by the number of weaners (ha ha) is actually the mean, in which case, there could be fewer long-term nursers, but because their age is higher, the mean (read average) is pulled up. Using the mean will naturally weight the average higher than if you use the median or mode.

    One might argue that using the mode would be the most accurate when saying "most children wean at age X" because age X would be the most repeated age without allowing a weighted factor (like the mean does) for older children or finding the age where there are an equal number to each side of the age stated.

    Yes, I am a math-geek.

    All of that being said, I agree. There should be MORE research to arm longer-term nursers more information. I think this is an area where research has lagged behind-- perhaps due to a lack of demand. Or maybe even complacency in the current situation.

  3. Blogger Annie | 9:29 AM |  

    I've long been a fan of Dettwyler's article on the natural age of weaning.

    I think people like to toss around the 4.5 average age to justify to others why it's okay to be nursing their 2-3 year old, but I think the information in her article is a far better way to explain to someone why extended nursing is biologically normal. That doesn't mean everyone can or should do it, but for those of us who do it is a biologically normal and reasonable choice.

  4. Blogger Jennifer Laycock | 9:32 AM |  

    Maria, nitpick away! This is why my readers rock. So many of them are so much smarter than I am in so many areas. ;)

    What's funny is I think I know you from other forums right? But it's your math talk and not your username that remind me. lol

    So can you define for me what the average is then? I always thought the average was when you add it all up and divide it and get a final number.

    Thus, to raise or lower the average, you have to have "balance" on either side.

    For instance, if you have this group:

    6 months
    12 months
    18 months
    24 months
    30 months

    the "average" is 18 months. If you had MORE age a lower age, you bring the average down.

    For instance...

    6 months
    12 months
    12 months
    18 months
    24 months
    30 months

    That brings the average lower than 18 months. On the other hand, if we would add another 24 month old in there, we'd once again put the average at 18 months because they'd balance each other out.

    Right? (Wrong? lol)

    When I said you have to have folks to balance it out, I didn't necessarily mean that for every 12 month old you'd literally need a 6 year old to balance. I meant more than you have to have those older ages entering in there to make up for the MASS numbers of children weaning prior to age 4.5.

    Does that make more sense or do I need to leave all the smarty-pants math talk to those of you who made it past Algebra II. ;)

  5. Blogger Jennifer Laycock | 9:35 AM |  

    Annie,

    I'm with you. I totally understand wanting to have those zingers to throw out there to silence the folks who are giving you (collectively) a hard time.

    As you note though, it seems as if it would be so much more productive to discuss the benefits of extended nursing and perhaps to draw comparisons of the natural weaning ages of other mammals.

    There's good information in that article. I hate to see it twisted into some phony stat when there are so many REAL reasons that can be used.

  6. Blogger Amanda | 9:38 AM |  

    I've never heard it called the "average age of weaning" when that number is thrown around. I've always understood it to say "This is how long it's believed that the natural term for nursing is in humans", NOT an "average". OR I've heard it stated like this: "When allowed to self-wean naturally, children will be done nursing around 4.5 years".

    I guess it just depends on who is making the comment. But regardless, the point is the same. Children who are nursed full-term are the minority in our country, and those that do practice CLW should not feel inferior for doing what they believe is best.

  7. Blogger Fat Lady | 9:59 AM |  

    First, let me say, that I'm not defending this statistic. I personally think that statistics are generally a load of bunk that can be manipulated to the users advantage - and have no real bearing on anything.

    However, I think, when most people use this number all they're trying to do is say something that sounds factual in defense of nursing an older child. I think a large number of people don't even know for certain what the term "average" means. I think for a lot of people it means - the majority, or even just a whole lot.

    Would it be better if they said, "A whole lot of people around the world nurse their children until they are over 4 years old"? Of course it doesn't sound official, but it's probably more accurate.

    As for how many children over the age of 4.5 are nursing - I think people might be surprised to discover that there's a whole lot more than they think.

    Since nursing my oldest, who is about to 9 years old, until she was 3 I have found that my attitudes about extended nursing have become more and more relaxed. And I've become more vocal about how much I support women who choose to let their children nurse until they are ready to stop.

    I've found that when people find out that I hold no judgments at all about extended nursing, they open up to me. I've had a number of women tell me, in confidence, that they nursed their children until they were 6 or 7 years old.

    No one would ever know, and these women would never admit it most people. I think there are a whole lot of women out there nursing their kids secretly for fear of being judged harshly.

    Which is another reason why I don't trust statistics. How can you get accurate numbers when there are so many people who won't admit to nursing.

    When people ask me when I'm going to stop nursing my youngest, who is 2.5. I tell them when she's ready. I don't bother with statistics. I just tell them that it's what's physically and emotionally best for her and her well-being is my primary concern.

    Of course that sounds even more determined than I actually am. I'd be happy if she weaned tomorrow and I'm willing to go as long as 3yo - but I don't know if I can take it much longer than that.

  8. Blogger Jennifer Laycock | 10:08 AM |  

    I'd have no problem with people throwing around the number if they aren't saying "the average age of weaning is."

    I've heard several folks say things like "biologically, it's thought that the average age of weaning should be around X" or "based on other mammals, we'd expect weaning to occur around" or things like that.

    Doesn't bother me at all.

    Honestly though, I'm surprised there hasn't been more research done on the longer-term impact of breastfeeding. I know there's not really any money in it, which can make it hard to find funding, but when you consider what long term health care costs are projected to be, you'd think it'd be worth spending some cash to find out if encouraging longer breastfeeding would really show some cold-hard data on decreased long-term health care costs.

    I also agree that there are probably a TON of women who simply aren't open about how long they nursed. That's a lot of cultural baggage to have to deal with, especially for those who go beyond the 4 year age range.

    We have a long way to go and a lot of attitudes to change, that's for sure.

  9. Blogger Eilat | 10:26 AM |  

    Sorry, Maria, Jennifer is right. I wasn't planning on pulling my PhD in Astrophysics out but...

    In a large normal (Gaussian) distribution the median --> mean. And since we are talking about worldwide breastfeeding rates, we are certainly in that regime.

    The mean can be (actually IS) defined the way Jennifer did, but another way to look at it is imagining a bell curve. In a normal distribution, the mean is the peak and the tail to the left and right are roughly symmetric. So there are as many people to the left of the mean as to the right.

    "but because their age is higher, the mean (read average) is pulled up."

    This makes no sense. You are saying that larger numbers are weighted more heavily in the average than smaller numbers. In a straight average, all numbers are weighted equally.

    If the distribution is not Gaussian and there are more members *below* the computed average, then to compensate, you can add fewer larger numbers to compensate. But since we are taking about worldwide breastfeeding rates, to compensate for all the 2.5 year olds who self-wean, you would need fewer (but still lots of them since we are talking about a worldwide phenomenon) much older nurslings. The oldest age I have ever encountered was age 7 or 8 in that video that Jennifer posted here a few months ago. Surely the rarity of these events are outliers, and are not enough to drag the average up.

    Math geeky enough for you? ;-)

  10. Blogger Maria | 10:51 AM |  

    Technically, average includes all three and unless the author indicates which s/he used, generally it is the median.

    I'll simplify your example for the sake of saving time/space.

    If you have just three children...
    6 months
    12 months
    18 months

    Your median would be 12 months.

    But...
    12 months
    18 months
    18 months

    Median = 16 months

    6 months
    6 months
    24 months

    Median = 12 months

    While this isn't as accurate of having 100 weaners...or thousands, you can see that having a weaner that is older would pull up the median (and younger brings it down). The more children, the less impact, but overall, the median can be impacted more dramatically by one child on the far end of the infininte spectrum.

    I think in our real life example-- making up for children who nurse little if at all, you would need to consider in cultures where the babies do wean later and their relative population size compared to the population size of "early" weaners. For example, a million 5 year olds in a 3rd World country versus 500,000 in a Westernized country... even if those 500,000 did not nurse at all, the median would be impacted more by the million who do nurse.

    Anyway, I just hate to see "average" used when we don't know which average is being used...or when multiple "averages" are used to describe the same statistic. Of course, there are lies, damned lies and statistics.

  11. Blogger Jennifer Laycock | 10:57 AM |  

    Woot. Keep it coming you two.

    You're making my head hurt, but it's very interesting. :)

  12. Blogger Eilat | 11:10 AM |  

    Maria, look up the definition of median.
    from the dictionary:

    Arithmetic, Statistics. the middle number in a given sequence of numbers, taken as the average of the two middle numbers when the sequence has an even number of numbers: 4 is the median of 1, 3, 4, 8, 9.

    So in your own examples:
    median(6,12,18)=12
    median(12,18,18)=18 NOT 16
    median(6,6,24)=6 NOT 12

    The median is LESS sensitive to outliers, which is what makes it such a powerful statistical tool.

    Furthermore:
    "a million 5 year olds in a 3rd World country versus 500,000 in a Westernized country... even if those 500,000 did not nurse at all, the median would be impacted more by the million who do nurse."

    Im sorry to say that breastfeeding rates, even (ESPECIALLY!) in developing countries are quite low.

    From Mothering magazine:
    "developing countries, which now have the lowest breastfeeding-initiation rates in the world. Sub-Saharan Africa has a rate of 32 percent; Asia, overall, 35 percent; Indonesia, 39 percent. In Vietnam, only 19 percent breastfeed, and in Thailand, only 5 percent."

    So while in small pockets of the world, where indigenous culture is strong, breastfeeding may go on to older ages, it is, sadly, by and large not the majority.

  13. Blogger Maria | 11:16 AM |  

    Sorry-- I didn't get to read Eilat's comments before posting. Astrophysics...crap, I'm just a lowly Economist. LOL!

    While in theory, I could agree with a normal distribution, I think a further look in to who is weaning when would indicated that the bell curve wouldn't be normal. Furthermore, using the bell curve, just because you have one 6 year old nursing, does not mean that you need to have a 3 year old to make the average 4.5. You could have 1- 6 year old and 3- 4 year olds... or 1- 6 year old and 2- 3.75 (45 month)year olds... and end up with the same result.

    Yes, in a larger sample size (or all inclusive if that's possible) with normal distribution that would work its way out, but population dynamics (and distribution) would come in to play, and I don't see that curve being normal.

    Again, without doing more research, I certainly could not say for sure, and as I am working on your dime (Fed employee), I'll refrain from doing such research now. Maybe I can use this for my thesis... find me a way to relate it to environmental science. :)

  14. Blogger Kathie | 11:20 AM |  

    Okay, not being a math geek, I am going to jump in and try to clarify. Maria is right, a high outlying number CAN adjust the average. So if we have a sample size of 10 kids, and let's say 7 of them wean at 1 year old, 2 of them wean at 2 years old, and 1 weans at 9 years old. Then the average age of weaning is 2 years old, right? Whereas if you leave the 9 year old out of the sample, then the average age of weaning is 1.1 years old. See how much it changed? NOW...Eilat is also right. With worldwide numbers, the chances of an extreme outlying number affecting the average is incredibly unlikely. If you have millions of 1 and 2 year old weaners, it would take an unbelievable amount of 9 year old weaners to adjust the average. You either need MORE weaners closer to the average age (say, 1 million 3 and 4 year old weaners) OR a lot (but less than a million) really, really OLD weaner. Does this make sense (and is it accurate? I'm not really a math geek, but I have taken some stats)

  15. Blogger Jennifer Laycock | 11:41 AM |  

    Maybe I should go back and retitle this "mythbusting statistics..."

    ;)

    Maria, I'm with you on what you're saying. I clarified a few comments back that I didn't actually mean you had to have the exact difference on each side (as in one five year old to balance every 3 year old.) I was simply breaking it down to the very basics in terms of "you have to balance to keep the average the same.) I realize one 6 year old can tilt the scales the same way as 2 4 year olds could.

    That said, I bow to Eliat's astrophysics degree. I've never been a numbers person, no matter how much I wanted to be.

  16. Blogger Eilat | 11:53 AM |  

    I am willing to concede that natural weaning age might not follow a normal distribution, but if it were a skewed distribution then it would be *harder* to reach an average of 4.5, not easer. That is, if the distribution were skewed so that there are more children self-weaning at earlier ages, which is what seems to be observed.
    In other words, for each 2 year old that self weans, you would need a 7 year old to bring the mean back to 4.5. But there are a lot more kids self weaning between 2-3 than 6-7.

  17. Blogger Jennifer Laycock | 11:59 AM |  

    In other words, for each 2 year old that self weans, you would need a 7 year old to bring the mean back to 4.5. But there are a lot more kids self weaning between 2-3 than 6-7.

    Ok, THAT's what I was trying to say in my original post that sparked all this debate.

    Thank you for saying it so it actually made sense. :)

  18. Blogger Eilat | 12:04 PM |  

    Thanks. And Kathy's description is exactly right (in words that everyone can understand ;-) ).

  19. Blogger Maria | 12:11 PM |  

    Yikes! I was not trying to start a fight or anything! I need to keep working, but I can't leave this discussion. It is WAY more interesting than my current project.

    Eilat-- I am fairly certain I said those were the MEANS not Medians. Personally, if I were making a "most" statement, I'd use Mode. And re: breastfeeding rates. I should have left the qualifiers off, as really, I was just trying to make an example with minimal research (or in this case none). I read just a few weeks back that in the US, the later-weaners are turning out to be mostly highly educated women-- not the "granola" stereo-type of old. Anyway, my mistake and error in judgement for not deleting or further clarrifying my example.

    Kathie-- thanks for the plain language. It's hard to KISS. ;-)

    I would guess that most (again, GUESS) babies aren't self-weaning at three months, but if they were, their lower ended spectrum could bring the average down too.

    Now-- who wants to sponsor some research? LOL!

  20. Anonymous Debby | 1:15 PM |  

    Ouch. This former English-major's head is starting to spin.

    Very interesting discussion, though!

  21. Blogger Ahmie | 1:58 PM |  

    if anyone might want to sponsor some research (or at the very least help me get a good size subject pool), I'm seriously considering planning to graduate school for a PhD in Social Psychology (Sociology-based) and this would fit right into what I plan to research anyway.

    What I'd specifically want to look at in this study is age of first introduction of solids and/or any other suppliments (potentially even bottled EBM), and separate out weaning before 6mo from weaning later, then look at what the distribution looks like for people who make it past 6mo, and factors that influence weaning, how often it's child-led vs. outside influence directed weaning (there are other reasons people wean besides mama being tired of it).

    Guessing hitting up Nestle to fund my research isn't gonna work, eh? ;)

  22. Blogger Heather | 2:14 PM |  

    I've always wondered about this "statistic". I hear it an awful lot, but any time I've challenged the person offering it to support it, they've never been able to provide a reliable source for it, of any kind.

    I don't use it, myself, for that reason.

    Thanks for the article; it's very informative, and it satisfies a curiosity I've had for a long time.

    And ahmie: I'd love to participate in such a study. I'll be starting the nursing journal again at the end of march... and I think I'm going to chronicle it thoroughly!

  23. Blogger Laureen | 3:05 PM |  

    OMG, I am sooooo laughing! Last I heard (I believe from T. Berry Brazelton, but I might be wrong on that), 4.5 years is the average age of *potty training* in America...

    From what I remembered of my early motherhood placenta-brained reading of Dettwyler, I thought that mammalian average weaning was when milk teeth dropped out... between 5 and 7, so that would make an average (or whatever the correct mathematical term is! LOL!) of 4.5 reeeeeeeeeeeeeeeealy tough to accomplish.

  24. Anonymous scarlett | 3:41 PM |  

    Ok now I know why I failed stats the first time only just passed the second time...

    This whole conversation might as well have been conducted in Martian for all the sense it made to me!

    I bow down to people who "get" statistics...

  25. Anonymous Anonymous | 3:59 PM |  

    In my studies, I believe I have seen this statistic attributed to WHO. I've also seen this in educational materials printed for my students. I found a couple links that might support this stat., but I couldn't fully access the one article. I will keep digging.
    http://www.google.com/search?q=world+health+organization+average+age+weaning&hl=en&safe=active&client=firefox-a&channel=s&rls=org.mozilla:en-US:official&hs=sOM&pwst=1&start=10&sa=N
    http://www.nacd.org/more_information/health/protocol.html

    For the record, the only time I used this statistic (and I believe I rounded down to 4) was when my pediatrician was pressuring me into weaning my 1 year old. He said it was "weird" to breastfeed past 15 months.
    Jennifer

  26. Anonymous Anonymous | 4:04 PM |  

    Here's another with a bibliography:
    http://www.llli.org/ba/Feb01.html

    Jennifer

  27. Blogger Ethel | 4:09 PM |  

    I tried to track this statistic down before once too, but never got a better source than the same article. I gave up and concluded that the information was just as outrageous as it sounds. I would love to know the real numbers, but 4.5 being the average age is just not a real reflection of the world.

    Thanks for playing the accuracy police for the breastfeeding movement here - I feel much better knowing that I wasn't the only one disturbed by that number, and I usually see it presented incorrectly (the average *is* 4.5, not that it should be or is biologically what we would expect, etc.).

  28. Anonymous Anonymous | 7:06 PM |  

    I read an article by an anthropologist once who said that human babies were designed to nurse from three to seven years. Which I guess was necessary, back in the days before rice cereal and, oh, I don't know, being able to cook your food until it's soft enough to feed to an infant or toddler.
    She was referencing what was done by human mothers millions of years ago, which has no bearing in today's society.
    THOSE are the numbers that really get my goat.

  29. Anonymous Melissa | 8:50 PM |  

    I have always wondered about that stat. I'm so glad that you have uncovered the real info behind it.
    And Ahmie, I'd love to participate in a study like that!

  30. Blogger JudyBright | 9:58 PM |  

    OK, math folk. Using big words others don't understand is useless.

    When analyzing statistics, mean, median, and mode are often used to figure out what happens the most often, or in this case, what's expected or normal for a group.

    The definition of mean and average are the same. You add up all the numbers and then divide by how many numbers there are. If you're looking at the weaning ages of 10 kids, you'll divide by 10 to get the mean or average.

    Median is the number that falls right smack dab in the middle if you listed all the numbers in order. There would be an equal number of numbers above and below that number.


    The mode is the number that occurs most often.

    So, for this list of numbers,

    1, 2, 2, 3, 5, 20, 86

    The median is 3. The mode is 2, and the average is 17.

  31. Anonymous Jessica | 6:33 AM |  

    I have read Dettweyler's piece also. Having been an evolutionary biology / sociology major, her methods make perfect sense to me, as does the large window she arrived at for weaning age for humans.

    What strikes me is that a hundred (or more) years ago, we wouldn't have even been discussing this. We'd just be nursing the kid until the kid stopped (or until we died!). Weaning has turned from a passive behavior into an active one, and I think the point that Dettweyler was making is that in the rest of the mammalian world, weaning is more passive on the mother's part. It's a cultural thing that has turned weaning into an active behavior.

  32. Blogger Mommy's Getaway | 9:04 AM |  

    The original post - VERY INTERESTING. Thank you! Very thought provoking!

    The comments - WAY over my Agricultural Communications head...I think I will have to re-read about 10 times to get it through my thick skull!

  33. Blogger Heather | 9:08 AM |  

    Anonymous 7:06:

    Rice cereal and being able to cook food is actually completely irrelevant. I don't know of a single extended nurser who exclusively nurses past a year. Nursing continues in addition to foods, and trust me, millions of years ago, they had the ability to cook. ;) It's that whole fire + water thing.

    Nursing until four may not be as relevant today as it did once upon a time, but the availability of commercially manufactured rice cereal and the ability to cook food are not the reasons.

  34. Blogger Anna | 9:14 AM |  

    It's a cultural thing that has turned weaning into an active behavior.

    Hmm... I'm not so sure about that. I'd suggest that a significant contributor to "active weaning" in humans is simply evolution. We have opposable thumbs, and we can cook.

    Even if a mother intends on practicing child-led weaning, the mere introduction of new and exciting foods is likely to encourage the child to wean more quickly than he would if his only nourishment were breastmilk. Even 100 years ago, I don't think extended nursing was common practice in industrialized nations. 100 years ago was 1908, after all. I'm pretty sure we had discovered fire by then. ;-) Not to mention, breastmilk substitutes existed LONG before the invention of formula. Milk from other animals and all sorts of crazy concoctions have been used to feed babies throughout history.

    Quite frankly, I don't think it matters how mothers fed their babies even 10 years ago, let alone 100 or 1000 years ago. To hold women living in today's culture up to a standard that was met for sheer *survival* 1000 years ago is unreasonable.

    None of this is to say I'm against child-led weaning or extended nursing - I'm all for it, when it makes sense for both the baby AND the mother. What I'm vehemently opposed to is holding up extended nursing as any sort of standard that all mothers should meet. Breastmilk is what a baby should have if at all possible for the first 12 months of life. Anything beyond that is definitely a bonus, but assuming mom and baby live in an industrialized nation and there are no other major health factors, a mother is not harming her child by weaning sometime after 12 months, particularly if it's done gently.

    While I can see the interest and benefit in studying mammalian behavior and drawing theories related to humans from it, the bottom line is that we humans are VERY different from our mammalian relatives, no matter how close our DNA is. It frustrates me to no end to see this research held up as "fact" by some people who want to force (or guilt) other mothers into fitting into their mold of what is best.

    Wow... /end rant. Sorry - this is a touchy topic for me this week!

  35. Anonymous LazyK77 | 9:58 AM |  

    Am I the only one feeling warm and fuzzy for the old CBC board? The exchange between Maria and Eilat took me back... I kinda miss those days and those crazy, WELL researched and documented discussions.

  36. Blogger Jennifer Laycock | 10:57 AM |  

    LazyK77, Ha! I was thinking the exact same thing!

  37. Blogger Housefairy | 2:22 PM |  

    I just wanted to chime in and say, yeah, I am usre that number meant a "very common age for children world wide to give up nursing"

    Of course, that being said, I am the only one of my friends whose kids nursed past age 3.

    Love your blog, dont let all this nit picking get you down
    :)

  38. Anonymous Mari | 8:06 AM |  

    Thanks for the info. It is good to know.

  39. Blogger Theresa | 1:08 PM |  

    FOOD FOR THOUGHT— WHY THE WEANING AGE OF ~4.2 MAKES PERFECT SENSE FROM A MATHEMATICIAN BREASTFEEDING MOM


    I ran across your blog when I was trying to find the average age of weaning worldwide. Unfortunately there’s an error in your mathematical reasoning. I got most of the following pieces of information from the UN website. The numbers are approximate but fairly close:

    DEVELOPED NATIONS make up approximately 14.766% of the world’s population.

    UNDEVELOPED NATIONS make up approximately 85.234% of the world’s population.


    Let’s say the average age of weaning in developed nations is approximately 1 year. I'm not sure if that's accurate, but not unreasonable. (The US makes up about 1/3 of the developed nations.)

    What would the average age in undeveloped nations be in order for the average worldwide weaning age to be 4.2?

    Let y=average age in undeveloped nations. (Let’s assume for ease of computation that 15% of the world is “developed” and 85% undeveloped):

    [ (15)(1) +(85)(y) ]/100 =4.2

    Solving for y, we get the average age of weaning in undeveloped nations is 4.72. (So "other people" would have to breastfeed til 4.72 yrs, and not 9 years as you suggested)

    While 4.72 may seem high to US citizens, imagine you did not have access to treated water, imagine the water you did have access to was limited, imagine you had no electricity for heat or cooling, you had limited food for your family, no medical care, no antbiotics and you could not read. Surely, under these circumstances we’d all breastfeed much longer than the socially accepted norm in the US. We would, because we'd know
    it could well save our children.

    I agree with some of the above posts: zingers are what matters here. As a mathematician, I’m constantly saddened by misuse of stats and erroneous reasoning. Our children have physical and emotional needs that are best met by breastfeeding, and we can trust our intuition and the wisdom of evolution to know that’s true.
    In my estimation, women in this country should have much more time with newborns. The real tradegy lies with the men, women and children who have so little and whom we overlook so often. When women worldwide breastfeed longer it’s for survival. I applaud any woman who breastfeeds her child til that mean age of 4.2 or beyond.

  40. Blogger Kathy R | 9:28 AM |  

    I ran into your article while researching two subjects - the average age of weaning in 3rd world nations and dairy products's relation to the risk of osteoporosis. (The math issue was a delight for me. I got my degree in math from UCLA. Your statement did sound like there was a mix up between mean and average.)

    I thought this website might be useful for the people reading your blog. It is titled, "Comparison of Infant Feeding Patterns Reported for Nonindustrial Populations with Current Recomendations." Wirtten by Daniel W. Sellen

    http://jn.nutrition.org/cgi/content/full/131/10/2707

  41. Anonymous Anonymous | 2:29 PM |  

    When you use the people you know or have met as "evidence" your credibility goes out the window. Lots of women breastfeed their children until they are much older but they don't tell people about it. Why? because so many people think it's weird! Americans think it's weird to use the breast to feed a baby or a young child, but don't care that it's used to sell everything from jeans to sunscreen. Breasts are meant to feed children- since it's the best food you could possibly give a child why would you stop just because some people think it's odd? Please, someone show me a study where a professional has found any evidence of harm to a child from breastfeeding. I have yet to find any evidence of harm from "extended" breastfeeding. I am currently nursing a 2 1/2 year old and a tenth month old and I can tell you many women have confided to me the true length of time they breastfed their children, something they wouldn't share with most strangers especially ones who might disapprove.

  42. Anonymous Anonymous | 2:55 AM |  

    In response to your comment which insinuates that no children aged 6, 7, 8 or even 9 would be still breastfeeding I would have to point out that you are unlikely to be aware of those people who choose to breastfeed for that long, since public opinion, particularly in Western cultures, tends to almost condemn this very normal practice. I should also like to inform you that I personally know several people who have breastfed their children for that long including myself. I breastfed my twin girls until they were 7 years old, my son still has an occasional breastfeed even though he is 9 and I also currently breastfeed my 3 year old daughter. With the age differences between my children it actually works out that I have breastfed for 13 consecutive years now and I know within myself that I have given my children the very best physical, mental and emotional start in life they could possibly have. Not everyone will want to breastfeed for as long as I have,but you need to be aware, as do your readers, that your comments are also not based on FACT but simply your own personal opinions.

  43. Anonymous Anonymous | 2:14 PM |  

    I would love better information on this subject-- what happens at/after 24 months.

    Dettwyler's article akes me feel okay about letting my son continue nursing at 22 montths. He loves it and I'm getting more and more pressure from family to stop.

    As a working mom, I cherish any attachment time he and I get and I think that's really hard for a lot of people to understand.

    At the same time, I just can't see whipping it out when he's 9...

    Cheers,
    Deb V

  44. Blogger THE PHONES | 8:10 PM |  

    Great response Teresa! I've gotten that stat off of WHO's website before and felt that it had to be pretty close. You put it in words much better than I could!

Leave your response

Links to this post: