Understanding Bone Density : Good Bone, Bad Bone, In-Between Bone

Osteoporosis. Now, there's a word you don't want to hear, right behind cancer and, "You've got to quit smoking." Porous bones. Brittle bones. Bones that go snap! Crackle! Pop!

No, not me. I'm talking about my wife, Pam. My 100-pound redhead took a bone density test in 2002. The doctor looked at the scan results. His jaw dropped. "You've got the bones of an 80-year-old woman!"

Great ego builder there, considering Pammie was 51 years of age at the time. Not to mention a lifetime athlete and a serious hottie. How could she face looking like one of the Three Witches with an old crone's hump, stirring the cauldron, boil and bubble, toil and trouble? No-o-o-o!

Sound familiar? To millions of people out there, it does. Especially (but not exclusively) to women and predominantly (but again, not exclusively) "older folks".

Her doctor prescribed a bone-building med. That one didn't work right for her, so he tried a different product.

That medication did work. My sweetheart began breaking lots and lots of bones at a very early age for a number of interwoven reasons. From long experience, she knows a hard hit is going to "break something". In recent years, since the medication regimen, she's bounced more, broken less. She logically wants to get a new bone density scan, see "how much bone she's rebuilt".

Which is a good idea, and we'll do that--when we can afford it. We're self-pay, cash and carry, which is just the way we like it. Besides, there's no rush.

Why not?

Because the results of a bone density scan taken after a person has been on "bone meds" for a time can be (in my opinion) somewhat misleading.

Why?

To explain that, we first need to take a look at the life cycle of bone and how bone medications work as described in the available literature.

It turns out that healthy bones are growing fresh, new bone constantly and sloughing off little tiny invisible specks of old, wornout, useless bone at the same time, all the time, till Death do us part. Out with the old, in with the new. Out with the old, in with the new.

When the speed of bone-growing meets or exceeds the speed of bone-dumping, we're in great shape.

This morning, I needed to explain all of this and more to Pam. She's known it, but one of her many ailments causes her to lose a bit of knowledge now and then, and we need to replace it to keep her mind functioning at its usual awesome level.

To help get the point across, I coined a few descriptive terms and quickly sketched a crude but effective visual aid in three parts: Good bone (Stone Bone), bad bone (Shell Bone), and in-between bone (Shell Bone plus Sand Bone). A "bit of bone" is shown as a simple bee-honeycomb type hexagon, which you'll not find in any literal photgraph of bone lattice, but close enough.

Relatively speaking, "tough bones" tend to have thicker (and therefore stronger) "calcium walls" with smaller spaces between the solid matter structures. One could think of it as a dense, impenetrable thicket of mature bamboo--hence the term, bone density.

That's good bone.

Duh.

But when the speed of new bone growth begins for any reason to lag behind the speed of bone-speck release (think of the "old outgoing bone specks" as specks of sand)...there's the rub. The "calcium walls" become thinner and thiner over time, with the interior spaces getting larger and larger, until what you have in your bone structure is literally a shell of its former self.

Ouch.

Now you have bad bone.

Okay. So far, so good.

So, tell me, Ghost, I take me some bone building medication the doctor prescribes. There's at least a chance I can rebuild my bones a bit, right?

Not exactly.

See, the bone medications currently availble do not build bone per se. That is, they don't work on the "incoming" side at all. They're not improving the rate at which your body is able to form new bone.

They're only slowing the release rate of old, wornout bone. That's all they do.

So...that's still good, right?

Yes...to a degree. See, those meds don't prevent the bone from deteriorating; they just make the skeleton hang onto those already wornout "sand specks" of "dead bone" for a bit longer than would normally being the case.

Uh...so?

So this: You've been on a good bone med for a while. You take a new bone density scan. The numbers are better, and you're once again ready to caper about, leaping tall buidlings in a single bound.

Not so fast.

What has been accomplished is not to produce a wonderful Fountain of Youth Stone Bone skeleton. Instead, it has cobbled together a hybrid situation never intended by Mother Nature: The old Shell Bone structure is still there, but now it's partially filled with tiny specks of Sand Bone waiting their turn to get recycled.

As in the illustration below.

Obviously, Shell Bone with Sand Bone will resist breaking under impact (such as hitting the floor when falling or smacking the corner of your desk when moving around the office) better than Shell Bone alone could ever do. That's a good thing.

On the other hand, it's not Stone Bone strong and never will be. It cannot be.

Which (finally!) brings us to an understanding about the somewhat misleading results of any bone density scan taken after implementation of a bone medication regimen.

Huh?

Okay, let's try this. Without going into the details (which would require another Hub), keep in mind that a scan score of -1 or above is really good, what a healthy woman in her twenties might expect to see. At -2.5 or lower, you've got osteoporosis. In between, you're headed for trouble, but you're not totally there yet. (That area is called osteopenia, in case you're into big words.)

Now, here's a totally B.S. example, because this much improvement "ain't happening", but to make the point, pretend your first test score came in at -2. Gotta start being careful.

Many months of medication later, your bone scan blows the minds of your doctors (which it would), coming in at -1. You've now got the bones of a youngster again, right?

Nope. Because the bone density scan has no way to tell the difference between Stone Bone versus Shell Bone with Sand Bone.

A realistic number, if it could tell the difference, might be something like -1.5. Definite improvement, but definely not rolling back to the Stone Bone years, either. (No Rolling Stone Bones? Dang.)

That's it for now. Discussion in the comments section should be interesting.