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A recent story, “Drugs to Build Bones May Weaken Them” on the New York Times website discusses a potential problem for those people who remain on osteoporosis drugs (a class of drugs called bisphosphonates that includes the drug Fosamax) for five years or longer. Various studies over the last several years have shown a tendency for long-term use of these drugs to result in unusual fractures occurring through the usually very strong middle portion of the femur (the thigh bone). Ordinarily fractures in this area occur only with major trauma or in extremely frail individuals.
While there will no doubt be considerable debate as to whether the drugs are to blame for the increased incidence of this unusual type of fracture, in my opinion, such fractures are actually expected when one is familar with the mode of action of these drugs.
To understand what’s going on, you need to know a little about how your bones repair and regenerate themselves. Inside the bones, there are cells that build them up (called osteoBlasts) and cells that break them down (caled osteoClasts). For healthy bones, you need to have a balance between the build up and break down of bone. In osteoporosis, several factors come together in such a way that the breakdown effects of the osteoclasts begin to outpace the build up processes of the osteoblasts.
Osteoporosis drugs work by inhibiting the function of the osteoclasts. This sounds like a good idea, doesn’t it? If you inhibit the osteoclasts, the bone doesn’t get broken down and bone density is maintained or even improved in some cases. But there’s more to the story.
Think about this for a minute. Do you think the body WANTS to have osteoporosis? Of course not! So, why would it even have cells (osteoclasts) to break down bone in the first place? There are two reasons. The first is that the bones are the body’s primary storage site for calcium. Blood calcium is extremely important to muscle function, including that very important muscle, the heart. So the body needs to have a supply of extra calcium on hand to keep the heart and muscles working and the osteoclasts are there to meet the body’s needs for blood calcium.
The second purpose of the osteoclasts gets to why anyone with any knowledge of human physiology (and perhaps also knows a little about engineering) should expect the osteoporosis drugs to cause an increase in fractures when used long-term. Bones are actually a complex matrix of calcium and other minerals and connective tissue. It is this matrix of minerals and connective tissue that give bones not only strength, but a certain amount of flexibility. Because bones must flex and absorb shock, if they were not constantly being recycled, they would be prone to the phenomenon that in engineering is called “metal fatigue” (that’s metal as in the strong shiny stuff, not mental). In engineering, it is well known that structural materials that are subject to flexing and shock absorption often become brittle over time. This is why aircraft are retired after a certain number of flights to avoid unfortunate incidents like wings falling off!
Well, if you prevent the bones from recycling (and the break down of bones by osteoclasts is necessary to the process), over time, it would be expected that the bones would become brittle. Just as the density of the metal in an aircraft may be perfectly normal when metal fatigue occurs, brittleness of the bones caused by osteoporosis drugs has nothing to do with the density of the bones. Osteoporosis drugs do maintain and sometimes improve bone density, but when used for too long would presumably (and apparently do) cause increased brittleness of the bones.
Although I favor more natural approaches to maintaining / improving bone density, I think that there are legitimate applications for osteoporosis drugs. But, we need to recognize that the potential benefits of such drugs may begin to be outweighed by their risks, particularly when used for an extended period of time.
Stay tuned to my natural remedies blog for upcoming posts on natural osteoporosis prevention.
Tags: Osteoporosis, bone density, calcium, fosamax, osteoporosis drug side effects, osteoporosis drugs
