ANSWER: Some steroid medications have been associated with osteoporosis in certain situations. The steroids found in a cortisone or similar injection, however, are unlikely to have an impact on bones because, after injection, the medication typically doesn't enter the bloodstream in significant amounts for any length of time.
Research has shown that corticosteroid medications can cause bone loss and result in osteoporosis if taken orally or intravenously (IV) in high doses or for long periods. (For example, prednisone taken orally in doses of more than 10 mg per day for longer than three months). Corticosteroids affect the bones primarily by decreasing bone formation but they may also increase the body's process of breaking down bone (bone resorption) when a person first begins to take the medication. Corticosteroids can also block the intestine's ability to absorb calcium while speeding up the loss of calcium through the urine, and both can have a negative effect on bone health.
These effects of corticosteroids occur when steroid medication circulates throughout the body in the bloodstream. In contrast, cortisone and similar shots are injected into a joint or into the spine, and the medication typically stays in the area where it is injected. That means little or no absorption of the corticosteroid into the bloodstream and, as a result, little or no effect on bones. It is possible that cortisone could leak slowly out of the injection area and enter the bloodstream in some patients but this is relatively uncommon.
For people with chronic conditions who need to take corticosteroid medications, such as prednisone or dexamethasone, in pill form or through an intravenous infusion that could cause bone loss, drugs are available to help prevent osteoporosis. Medications used to treat osteoporosis—alendronate (Fosamax), ibandronate (Boniva), risedronate (Actonel), zoledronic acid (Reclast) or teriparatide (Forteo), for example—have also been approved by the U.S. Food and Drug Administration to decrease bone loss in those taking long-term corticosteroid therapy.
But the situations in which people may need to take corticosteroids for decades are quite different from the patient who receives an occasional cortisone injection. If your doctor recommends a steroid injection to decrease joint or back pain, or to treat another condition, you should have the injection. You are likely to obtain benefits from the treatment, and the risk that it will do any harm to your bones is low.—Bart Clarke, M.D., Endocrinology, Mayo Clinic, Rochester, Minn.
(Medical Edge from Mayo Clinic is an educational resource and doesn't replace regular medical care. To submit a question, write to: firstname.lastname@example.org, or Medical Edge from Mayo Clinic, c/o TMS, 2225 Kenmore Ave., Suite 114, Buffalo, N.Y., 14207. For health information, visit www.mayoclinic.com.)