Frequency of osteopenia in children and young adults with childhood-onset systemic lupus erythematosus

Objective. To determine the frequency of osteopenia in patients with childhood-onset systemic lupus erythematosus (SLE) compared with that in healthy matched controls, and to evaluate the relationship between disease-related variables and bone mineral mass. Methods. Bone mineral density (BMD) and bone mineral content (BMC) were measured in a cohort of 70 patients with childhood-onset SLE (mean +/- SD disease duration 10.8 +/- 8.3 years, mean +/- SD age 26.4 +/- 9.9 years) and 70 age- and sex-matched healthy controls. BMD and BMC of the femoral neck, lumbar spine, total body, and distal one-third of the radius were measured by dual x-ray absorptiometry. We investigated the relationship between BMC and the following disease variables: cumulative dose of corticosteroids, organ damage, current use of corticosteroids, use of cyclophosphamide, age at disease onset, and disease activity at the time of diagnosis. Biochemical markers of bone metabolism were also measured. Results. BMD values for the lumbar spine and femoral neck were significantly lower in patients than in healthy controls. The reduction in BMD of the lumbar spine was significantly greater than that of the total body. In multiple linear regression analyses, a higher cumulative corticosteroid dose was significantly associated with lower BMC of the lumbar spine and femoral neck. Decreased lumbar spine BMC was also related to male sex. Conclusion. The frequency of osteopenia was higher in patients with childhood-onset SLE than in matched controls. The lumbar spine was the most seriously affected skeletal site, followed by the femoral neck. The cumulative dose of corticosteroids was shown to be an important explanatory variable for BMC values in the lumbar spine and femoral neck.