ALTERED MINERAL METABOLISM IN GLUCOCORTICOID-INDUCED OSTEOPENIA - EFFECT OF 25-HYDROXYVITAMIN-D ADMINISTRATION

Parameters of mineral and bone metabolism were studied in 17 patients treated chronically with supraphysiologic doses of glucocorticoids. When compared to 15 matched normal subjects, the patient group exhibited similar serum 25-hydroxyvitamin D (25-OHD) levels, decreased intestinal 47Ca absorption, increased serum immunoreactive parathyroid hormone, and decreased forearm bone mass. Iliac crest bone biopsies revealed a decreased bone formation rate and increased osteoclast number. Treatment with 25-OHD (mean dose 40.3 μg/d) and calcium (500 mg/d) in nine patients produced a 46% increase in 47Ca absorption (P<0.001) and a 54% decrease in serum immunoreactive parathyroid hormone (P<0.001) by 3 mo. In addition, by 12 mo the treatment group exhibited (a) a 13.2±5.1% increase in metaphyseal (P<0.001) and a 2.1±0.4% increase in diaphyseal (P<0.05) forearm bone mass, and (b) significant decreases in cortical and endosteal osteoclast number. Biochemical and bone mass changes persisted through 18 mo. No signifcant changes in any parameter occurred in eight control patients administered calcium 100 mg/d. It is concluded that treatment with 25-OHD and calcium can significantly improve parameters of mineral and bone metabolism in patients with glucocorticoid-induced osteopenia.