Bone mineral density in children with systemic lupus erythematosus and juvenile idiopathic arthritis: A cross-sectional study in a tertiary care hospital from Eastern India

Objectives: To determine the Bone Mineral Density (BMD) of paediatric Systemic Lupus Erythematosus (pSLE) and Juvenile Idiopathic Arthritis (JIA) patients and determine its association with predefined variables.
Method: This was a cross-sectional study involving consecutive pSLE and JIA patients attending the paediatric rheumatology clinic. Healthy age and sex matched controls were selected from neighbouring schools. BMD was assessed  at the lumbar spine  by Dual Energy X-ray Absorptiometry (DEXA) scan and expressed as Z-score. Its correlation with variables like Body Mass Index (BMI), onset of puberty, disease duration, disease activity, duration of steroid intake and cumulative dose of steroids was assessed.
Results: There were 45 cases (33 JIA, 12 SLE) and 23 controls. DEXA Z-score of cases (-1.58±1.22) was significantly lower than controls (0.096±1.19).  BMI and onset of puberty also differed significantly between cases and controls. However, there was no significant difference in  DEXA Z-scores of pSLE and JIA. There was a significant  negative correlation of DEXA Z-score with disease duration, duration of steroids and cumulative steroid dose. However, there was no significant correlation with disease activity. There was a significant positive correlation with BMI .
Conclusions: Patients with pSLE and JIA had significantly less DEXA Z-scores compared to healthy matched controls. Major contributing factors were disease duration, duration of steroid intake and their cumulative dose.