The aim of our study was to assess bone mineral density (BMD) in pre-menopausal women with systemic lupus erythematosus (SLE) and the influence of disease activity and use of corticosteroids. Lumbar and femoral BMD were measured in 43 patients with SLE (28 on regular steroid therapy, 15 with recent onset, non-treated) and compared with 43 healthy women matched for age. In addition, 21 SLE patients treated with corticosteroids were followed-up with a mean of 36.6 +/- 12.7 months. BMD was significantly lower in SLE patients with prednisone doses > or = 7.5 mg/day than those of recent onset (lumbar: 1.07 +/- 0.11 vs 1.15 +/- 0.13, P = 0.039; femur: 0.85 +/- 0.13 vs 0.98 +/- 0.21, P = 0.034) and the control group (lumbar: 1.07 +/- 0.11 vs 1.13 +/- 0.10, P = 0.040; femur: 0.85 +/- 0.13 vs 0.93 +/- 0.10, P = 0.028). In addition, 18% of SLE steroid users had osteoporosis. Lumbar and femoral BMD were inversely correlated with the time of treatment and the cumulative doses of prednisone. There were no significant BMD changes during the 3-yr follow-up period. In conclusion, in SLE pre-menopausal patients lumbar and femoral BMD is decreased and related to long-term corticosteroid therapy.