Bone Mineral Content And Fractures: Are They Related?
- Image by Woody Collins via Flickr
In a previous post on the relationship between structural “deviations” and pain symptoms we discussed how specific issues such as “disk protrusions” and “torn rotator cuffs” are not necessarily related to pain symptoms – regardless of what well-meaning health practitioners may tell us.
Now, let’s talk about a related idea we first touched upon in our podcast with Ruthy Alon. Namely, is low bone mineral content the cause of bone fractures?
Bone Density and Bone Fractures
It is well established that most women lose bone density as they get older (Citation: Hip and calcaneal bone loss increase with advancing age.) But what is puzzling is the fact that bone fractures – presumably related to bone density and bone mineral content – varies among populations. For example, African American women have much lower rates of bone fractures than do Caucasian women.
Why? Is it because African American women have stronger bones? Do they have slower mineral loss? For the U.S. population, I have not seen an answer. However, I was intrigued by this comment by Ruthy Alon on a Facebook post (African Women Walking):
“Comparative research shows that African women, who carry massive loads on their heads
with effortless grace, are one hundred times less liable to fractures than women in the West,
despite the fact that their bone density is lower than that of Western women.”
Could this be true? Do African women, with dramatically fewer bone fractures than Caucasian women have actually have lower bone density? If so, what accounts for the differences in fracture rates?
Bone Density Research
According to a study in the Journal of Bone and Mineral Research Ruthy is correct. The study compared Caucasian women and African women on a variety of factors including bone density, age, and weight. Surprisingly, not only did the African women maintain bone density at a similar rate to Caucasian women, but they actually had LESS overall bone mineral content than did the Caucasian women. Got that? Lower bone density and fewer fractures.
According to the researchers,”These results challenge the concept of BMC [Bone Mineral Content] as a primary determinant of fracture risk.”
If bone density is not the “cause” of fractures, then what is? How do African women avoid fractures? What can Caucasian women learn from them? Would anyone like to share a theory? If you are a Feldenkrais Practitioner or Bones For Life Practitioner, you likely have an opinion on this. Yes?
I’m listening.
![Reblog this post [with Zemanta]](http://img.zemanta.com/reblog_a.png?x-id=5d1b3478-902d-4cbd-b799-eefd8086b6cd)
(I have no expertise at all in this area.) My understanding is that resistance training (lifting weight) increases bone strength. I suppose, to the degree I thought of it at all, I always thought that resistance training increased bone density. Given your post, I’m guessing resistance training doesn’t increase bone density but produces other changes (unspecified). One conjecture is that such unspecified changes may be in the structure of the open spaces within bone tissue such as some sort of honeycomb lattice which would be both lighter and stronger. Bones are porous; so I’m thinking one possibility is that, challenged by more weight, they might self-organize an efficient, light, strong shape for the open spaces within the bone.
Ryan,
First you say “African-American” women, then “African”. I assume the first one is a typo. Are you saying “Caucasian” women have more fractures than women of African ancestry, or is that American or European women (regardless of ancestry) have more fractures than actual African women– presumably of a certain tribe and nationality, with a particular lifestyle, perhaps involving carrying loads on the head? What about African-American soccer moms vs. European-American soccer moms?
Here’s an article that confirms a lot of what you said in your post:
Phys Ed: The Best Exercises for Healthy Bones
By GRETCHEN REYNOLDS
find it at
http://well.blogs.nytimes.com/2009/11/11/phys-ed-the-best-exercises-for-healthy-bones/
You know, as a surgical neurophysiologist, I’ve been involved in a lot of spine surgery. A lot of it. I’m aware that everything we believe in western scientific medicine is not necessarily so; I understand that sometimes people have surgery and don’t feel better, and sometimes people get better without the surgery. It doesn’t mean, as some Feldenkrais people would love to believe, that surgery is never necessary, that everything about WSM is wrong, that Feldenkrais has a magic cure for everything, or that there is no connection at all between structural abnormalities and pain. Yes, you can have a disk protrusion and no pain, or pain with no disk protrusion; but if you have a disk herniation and it’s pressing on a nerve root, if it’s bad enough, you will have pain. Similarly, okay, you can have reduced bone calcium and not break a bone, and you can break a bone even if your calcium is high, but that doesn’t mean it isn’t a good idea to have adequate levels of it.
Just because the relationship between exercise and mineral content or bone density, or the relationship between those bone characteristics and frequency of fractures, is not as simple and straightforward as we might have thought, doesn’t mean it doesn’t exist.
For example, maybe what you need to resist fractures is not a big, dense, “dumb” bone, but a lean, mean, flexible bone with just enough mass in just the right places. Maybe it also helps to have just the right type and amount of flexibility in the joints; maybe it also helps to be flexible, agile, and balanced in your movements, so you don’t put undue stress on the bones or joints, or don’t fall down and break something.
Further research…
Jerry – Thanks for the comment. I love these two quotes from the article you linked to:
“An emerging scientific consensus seems to be, he says, that “large forces released in a relatively big burst” are probably crucial. The bone, he says, “needs a loud signal, coming fast.” For most of us, weight lifting isn’t explosive enough to stimulate such bone bending. Neither is swimming. Running can be, although for unknown reasons, it doesn’t seem to stimulate bone building in some people. Surprisingly, brisk walking has been found to be effective at increasing bone density in older women, Dr. Barry says. But it must be truly brisk. “The faster the pace,” he says — and presumably the greater the bending within the bones — the lower the risk that a person will fracture a bone.”
I am slightly skeptical of what they are saying above. I wonder what would happen with people who did a number of different activities consecutively – swimming, running, weight lifting and thus had stress on the bones in a variety of ways vs a group doing one repetitive activity.
The quote below, reminds me of what I have seen some of Ruthy Alon’s students doing:
“In the meantime, the current state-of-the-science message about exercise and bone building may be that, silly as it sounds, the best exercise is to simply jump up and down, for as long as the downstairs neighbor will tolerate. “Jumping is great, if your bones are strong enough to begin with,” Dr. Barry says. “You probably don’t need to do a lot either.” (If you have any history of fractures or a family history of osteoporosis, check with a physician before jumping.) In studies in Japan, having mice jump up and land 40 times during a week increased their bone density significantly after 24 weeks, a gain they maintained by hopping up and down only about 20 or 30 times each week after that.
You wrote this
“It doesn’t mean, as some Feldenkrais people would love to believe, that surgery is never necessary, that everything about WSM is wrong, that Feldenkrais has a magic cure for everything, or that there is no connection at all between structural abnormalities and pain.”
I’ve actually never heard a Feldenkrais Practitioner make those types of arguments – and even if a few did – it certainly wouldn’t speak to the beliefs of an entire community.
- Ryan
Tom – Thanks. I will need to upgrade my knowledge of the bones and bone structure before I can respond meaningfully. Bones are clearly affected by and adapt to experience. I suppose the question is how to engender the most durable and yet flexible organization. – Ryan