To investigate the effect of low doses of 2 different glucocorticoids on bone mass, sex hormone status and bone metabolic indices, a study was undertaken in 16 postmenopausal women with rheumatoid arthritis (RA) receiving < 15 mg/day of deflazacort and in 16 patients with RA matched for age, years postmenopause and disease duration, receiving < 10 mg/day of prednisone. Sixteen healthy postmenopausal women and 16 nonsteroid treated patients with RA were also studied as control groups. Vertebral bone density (vBMD) was lower (mean +/- SD: 0.65 +/- 0.07 vs 0.73 +/- 0.09 g/cm2; p < 0.02) in prednisone treated patients than in deflazacort treated patients, whose vBMD values were similar to those of nonsteroid treated RA. No significant difference was found as for radial bone mineral content. Circulating levels of estradiol, dehydroepiandrosterone sulfate, androstenedione and progesterone were low in all patient groups with RA when compared with healthy controls. The prednisone treated patients showed significantly lower values of all sex hormones with respect to deflazacort treated patients. Osteocalcin values were also lower (3.0 +/- 1.4 vs 3.9 +/- 1.6 ng/ml; p < 0.05) in prednisone treated patients with respect to deflazacort treated group. Glucocorticoid treated patients showed a direct correlation (r2 = 0.39) between vBMD and plasma estradiol levels, while no correlation was found with osteocalcin values. In conclusion, our postmenopausal patients with RA treated with low dose prednisone had reduced levels of sex hormones and osteocalcin and reduced vertebral bone mass. Comparable doses of deflazacort showed only a mild inhibitory effect on sex hormones and osteocalcin, and did not show any detectable effect on bone mass.