Rheumatoid arthritis: evidence for bone loss in premenopausal women

To assess bone mineral density (BMD) status in patients with rheumatoid arthritis (RA).

Rheumatoid factor-positive premenopausal women with RA meeting the American College of Rheumatology criteria were enrolled. Exclusion criteria included diseases or drugs that affect BMD, except for glucocorticoids, and smoking. Evaluation consisted of a questionnaire, physical examination, and laboratory tests. Lumbar spine and right proximal femur BMD were measured with a DPX-Lunar DEXA scanner. Data were analyzed by Student t test, chi-square, and multivariate analysis.

We studied 78 patients with RA and 39 controls; 82% were Caucasian, with mean age 35.5 +/- 6.7 years, and mean disease duration 48 +/- 51 months. Among patients, 74.4% had been treated with glucocorticoids, with a mean daily dose of 9.7 +/- 5.9 mg. Mean lumbar spine BMD was 1.157 +/- 0.124 g/cm2 in the RA patients, and 1.223 +/- 0.147 g/cm2 in controls (p < 0.01). Mean right proximal femur BMD did not differ significantly. Lumbar spine osteopenia correlated with "no physical activity at work" status, low body weight, and duration of glucocorticoid therapy. Femoral neck osteopenia correlated with "no physical activity at work" status, Steinbrocker class III, erosions of the hands, and high erythrocyte sedimentation rate (ESR). Trochanteric osteopenia correlated with "no physical activity at work" status, erosions on hand radiographs, low body weight, high ESR, and anemia.

Patients with RA of relatively short disease duration already exhibited significantly lower lumbar spine BMD. The identification of prognostic markers for bone loss in patients with RA should not only prompt early therapeutic intervention, but also facilitate early preventive measures.