ORAL AND INHALED CORTICOSTEROIDS REDUCE BONE-FORMATION AS SHOWN BY PLASMA OSTEOCALCIN LEVELS

Osteoporosis is a well-known, serious com plication of long-term high-dose corticosteroid therapy. This study was performed to determine the effects of commonly used doses of oral and inhaled steroids on biochemical indices of bone formation. Initially we examined the long-term effects of oral steroids. Thirty-four outpatients with symptomatic asthma or chronic obstructive airways disease (GOAD) receiving long-term oral prednisolone (mean 10.1 mg daily) were compared with 34 control subjects with asthma or GOAD matched individually for age, sex, and menopausal status who were not taking oral steroids. Plasma osteocalcin concentrations were significantly lower (patients 6.3 +/- 0.1 ng/ml; control subjects 8.6 +/- 0.5 ng/ml, mean +/- SEM; p < 0.01) in patients on steroids with no difference in alkaline phosphatase. To examine the short-term effects of oral and inhaled corticosteroids, healthy male volunteers were given a 7-d course of either 15 mg oral prednisolone daily (n = 10) or 500 mu g inhaled beclomethasone twice daily (n = 20). After 1 wk of oral prednisolone, mean plasma osteocalcin decreased from 11.8 +/- 1.1 ng/ml to 6.9 +/- 0.8 ng/ml (p < 0.001). With inhaled beclomethasone mean plasma osteocalcin decreased from 11.6 +/- 0.6 ng/ml to 9.6 +/- 0.6 ng/ml (p < 0.001) with no change in alkaline phosphatase. in doses routinely prescribed for the prophylaxis and treatment of asthma, oral and inhaled steroids suppress osteocalcin levels and may therefore inhibit bone formation. This effect is seen with short courses of steroids and also with chronic administration. In the short term, the fall in osteocalcin with 1 mg inhaled beclomethasone is significantly less than that with 15 mg oral prednisolone. Because patients on low-dose inhaled beclomethasone may require fewer courses of oral steroids, prospective studies in patients with chronic asthma are required to assess the effect of low-dose prophylactic inhaled beclomethasone on bone density and fracture rate before any changes to the present use of inhaled steroids are made.