Bone mineral content in patients with rheumatoid arthritis: relationship to low-dose steroid therapy

Bone mineral content (BMC) of the distal forearm was measured by single photon absorptiometry in 142 patients with rheumatoid arthritis (RA) of whom 27/54 men and 44/88 women received low-dose steroid therapy (less than 10 mg/day). To study the effect of steroid therapy a case-control analysis was undertaken in patients matched for age, sex and disease duration. Steroid therapy was associated with a reduced BMC in men (1.16 +/- 0.29 versus 1.32 +/- 0.23; P less than 0.05) and post-menopausal (0.76 +/- 0.24 versus 0.91 +/- 0.25; P less than 0.02) but not pre-menopausal women (1.1 +/- 0.28 versus 1.1 +/- 0.17). Symptomatic fractures were more common in steroid-treated patients than in those who had not received steroids (10/71 versus 2/71; P less than 0.05). Serum osteocalcin, an index of bone formation, was measured in 106 cases. It tended to be higher in patients with RA than in controls but the values observed in steroid and non-steroid RA groups did not differ significantly. We conclude that low-dose steroid therapy is associated with increased bone loss and numbers of fractures in patients with RA but this does not appear to be the result of a simple defect in bone formation.