Bone mineral density in systemic lupus erythematosus and its relation to age at disease onset, plasmatic estradiol and immunosuppressive therapy

The aim of this paper was to evaluate bone mineral density (BMD) in patients with systemic lupus erythematosus (SLE), to determine the role of corticosteroids and cytotoxic drugs and to assess estrogen effect on BMD in SLE.BMD (DEXA) at lumbar vertebrae (L2-L4) and at femoral neck was performed in 60 pre-menopausal SLE patients and in 64 controls. Estradiol level was measured in all the individuals. Age, age at disease onset, body mass index (BMI), time of disease, disease activity (SLEDAI), prednisone dose at the evaluation, total cumulative and cumulative prednisone dose in the last year and cytotoxic drugs were assessed.The mean plasmatic estradiol was 175.9 pg/ml in patients and 149.9 in controls. BMD was inferior in patients than that in controls (P0.0001). The mean current, cumulative and previous year prednisone doses were, respectively, 19.17 mg/d, 28.78 g and 5.33 g. There was no association between corticosteroids or cytotoxic drug used and low bone mass. The serum concentration of estradiol did not influence the bone mass. The BMI and age at disease onset exhibited an influence on BMD at L2.BMD was significantly lower in SLE patients but not related to CS (Corticosteroids)or other drugs; the estradiol in these patients had no effect on BMD. Low BMI interacting with early onset of disease might influence the probability of loss of bone mass.