Common osteoporosis medication may entail uncommon side effect

Researchers from various dental schools across the U.S. recently collaborated on a study that assesses the extent to which bisphosphonates, a common treatment for osteoporosis, are associated with osteonecrosis of the jaw (ONJ).

Their findings, which appear in the Journal of Dental Research (JDR), indicate that bisphosphonates can increase the likelihood of the degenerative jaw condition by a significant amount.

Osteonecrosis of the jaw occurs when blood vessels leading to the facial bones deliver too little blood supply, causing sections of those bones to die and decay, according to the Mayo Clinic.

Researchers determined that oral bisphosphonate use can increase the risk of ONJ more than 15-fold.

The team, who performed their research at the Kaiser Permanente Center for Health Research and HealthPartners Research Foundation, was careful to note that these findings do not indicate that ONJ is a common condition.

On the contrary, their research indicated that a commonly cited figure may overestimate its prevalence by a factor of 10. Lead author Jeffrey Fellows said that while many studies have estimated that 1 percent of people using bisphosphonates for osteoporosis develop ONJ, the actual number may be closer to a tenth of a percent.

He added that "the risk is still real and patients should take necessary precautions, but they shouldn't be alarmed."

Bisphosphonates operate by discouraging the actions of osteoclasts, which are specialized cells that break down bone tissue. By preventing this process, corresponding bone-producing cells can then add to bone density.

However, for almost a decade, doctors have noted a moderate increase in ONJ among those who take this class of medications. The first studies indicating this connection appeared in 2003, the Mayo Clinic reports.

A separate study also published in the JDR determined that intravenous bisphosphonates may entail an even greater risk for ONJ among people with osteoporosis.

Ultimately, both studies found that the overall ONJ-related risk for bisphosphonate use is low, particularly when considering the drug's positive health effects.

Osteoporosis can cause fractures that take their toll on both personal independence and public health costs. In 2005, osteoporotic fractures cost $17 billion in U.S. healthcare spending, according to the International Osteoporosis Foundation.