Low Serum Osteocalcin Levels in Glucocorticoid-Treated Asthmatics*

Abstract

Serum osteocalcin (OC) levels were measured in 19 asthmatic patients receiving long term glucocorticoid therapy and in age- and sex-matched asthmatic patients not receiving this treatment. In the glucocorticoid-treated patients, the meanOC level was approximately 50% less than that in the control group (P < 0.001), and there was a direct correlation between serum OC and 1,25-dihydroxyvitamin D [1,25-(OH)²D; r = 0.71; P < 0.001]. Multiple regression analysis in a total of 39 glucocorticoid- treated patients indicated that OC correlated directlyto 1,25-(OH)²D and inversely to glucocorticoid dose. There was no correlation between OC and 1,25-(OH)²D in the control group and no significant difference in mean serum 1,25-(OH)²D between the steroid-treated asthmatic patients and the asthmatic control patients. The effect of a 4-day course of oral 1,25-(OH)²D on serumOC was studied in six patients with glucocorticoid excess and six normal subjects. There was a similar percent increase in OC levels in both groups, though the basal concentrations and absolute increases were substantially less in the steroid-treated group. It is likely that the depression of serum OC in glucocorticoidtreated patients results from the reduction in the rate of bone formation induced by these hormones.