Frequency of Low Bone Mineral Density and Its Associated Factors in Patients with Juvenile Systemic Lupus Erythematosus

Objective: To evaluate the frequency of low bone mineral density (BMD) in Chinese patients with juvenile systemic lupus erythematosus (JSLE) and the associated protective and risk factors. Methods: We evaluated the BMD in 21 patients with JSLE with a mean age at diagnosis of 13.6±2.1 years. All patients had at least one BMD measurement by dual-energy X-ray absorptiometry at lumbar spine (L2-4) and femoral area at or beyond the age of 18. The correlations between BMD and cumulative dose of steroids, disease duration, disease activity, disease-related damage, clinical features, body mass index and age were investigated. Results: 'Low BMD for chronological age' (Z-score ≤-2.0) at one or more sites was seen in three patients (14.3%) and 'osteopenia' (Z-score -2.0) at any site was present in 12 patients (57.1%). Multiple linear regression analyses showed that body mass index was a positive predictor for BMD at all sites. Cumulative steroid dose, disease activity or lupus nephritis were not related to low BMD. Conclusions: Low bone mineral density is a common problem among Chinese patients with JSLE. Lower body mass index was shown to be a possible risk factor for low BMD.