Recent bone health news once again remind us that our bodies are not as simple as we would like.
These reports indicate that some women taking “bone-strengthening” prescription drugs have suffered unexpected hip fractures from apparently trivial causes.
These atypical femur fractures are associated with long term treatment with bisphosphonates, specifically alendronate (Fosamax). Long term use was from four to eight years.
The fractures were not from falls. In most cases, individuals were performing low-energy exercise, or just walking down a flight of stairs.
Biphosphonates are a category of drugs that inhibit bone resorption. Studies have shown that this therapy therefore improves bone density and apparently decreases fracture risk. The biphosphonates include alendronate, risendronate and ibandronate.
The drugs suppress bone turnover, which is the complication with long term use. While they improve bone density, they are not necessarily improving bone quality, as the unexpected fractures attest.
Our bodies want to adapt to demands we make upon it. If we lift weights enough, our muscles get stronger. If we jump up and down, our leg bones get stronger to deal with the added gravity stress.
With biphosphonates, however, while we move forward in our life, the ability of our bones to adapt to changing circumstances is left behind. The natural ability of our body to remodel bone – both remove bone cells and add new ones – is inhibited.
Two preliminary studies presented at the 2010 annual meeting of the American Academy of Orthopedic Surgeons suggest that long term suppression of bone remodeling by bisphosphonates may alter material properties of bone, potentially affect the bone’s mechanical integrity and could contribute to the risk of atypical fractures.
Deborah Pate, D.C., a longtime contributor to the “Dynamic Chiropractic” publication, writes in her article on “Long-Term Bisphosphonate Use and Increased Fracture Risk”:
“Present conclusions are that during long-term therapy, severe suppression of bone turnover may occur, resulting in increased susceptibility to nonspinal fractures along with delayed healing. Current evidence suggests that bisphosphonates should be stopped after five years. Patients who remain at a high risk of fractures or who have had fractures despite bisphosphonate therapy could be considered for treatment with intermittent PTH (parathyroid hormone). In otherwise healthy perimenopausal women who merely have osteopenia, the best therapeutic option is probably not bisphosphonates.
“Studies have shown the efficacy of bisphosphonates in the first five years of therapy improving bone density and diminishing the risk of fractures. After that, however, until additional studies are done that clarify the risks of nontraumatic fractures, the delayed healing of bone fractures associated with long-term treatment with bisphosphonates, and which risk factors, if any, can help predict which patients are at increased risk of these adverse affects, it is reasonable to suggest patients stop the drug, continue weight-bearing exercises, take calcium supplements and have their bone density monitored with DEXA.
“Weight-bearing exercise is essential for the prevention and treatment of osteoporosis and unfortunately, it is often overlooked or underemphasized. Muscle strength is an accurate predictor of bone strength. “
(For Dr. Pate’s compete article, go to www.dynamicchiropractic.com and use the Search box.)