PARATHYROID HORMONE AND 25‐HYDROXYVITAMIN D LEVELS IN GLUCOCORTICOID‐TREATED PATIENTS

Abnormalities in parathyroid hormone (PTH) secretion or vitamin D action or metabolism have been suggested as pathogenetic factors in the bone disease associated with chronic glucocorticoid therapy. We have found normal plasma PTH values in forty‐eight adult asthmatic patients on chronic glucocorticoid therapy, twelve asthmatics treated without glucocorticoids and ten adults on short‐term, high‐dose glucocorticoid therapy for non‐asthmatic illnesses. The mean serum 25‐OHD level in the glucocorticoid‐treated asthmatics was not significantly different from a disease control group of asthmatic patients not on glucocorticoids, but nine such patients had abnormally low 25‐OHD levels. Our results indicate that in asthmatic patients on chronic glucocorticoid therapy: (1) PTH and 25‐OHD values are usually normal regardless of dose or duration of therapy and (2) there is a subset of patients with low 25‐OHD values which may reflect unusual sensitivity to glucocorticoids.