Quantitative ultrasonometry of the calcaneus in children with juvenile idiopathic arthritis

Objectives. To evaluate bone quality by means of quantitative ultrasonometry (QUS) in children with juvenile idiopathic arthritis (JIA). Methods. Seventy children [37 with oligoarticular JIA, mean age (+/- S. D.) 10.54 +/- 3.42 yr; and 33 with polyarticular rheumatoid factor negative JIA, mean age (+/- S.D.) 11.33 +/- 2.88 yr] were enrolled. Quantitative ultrasonometry was measured on both heels with a Cuba Clinical portable device. Body height, weight and body mass index were recorded together with disease duration and cumulative dose of prednisone. Results. The lowest QUS parameters were observed in children with polyarticular JIA (P < 0.001 and 0.01 when compared with reference data and oligoarticular JIA, respectively). In children with oligoarticular JIA, the QUS values were also significantly lower in comparison with the reference data (P < 0.002). The QUS parameters were strongly influenced by body height, and to a lesser degree by body weight. In children with polyarticular JIA, there were significant inverse correlations between QUS parameters and disease duration [r=-0.57, P < 0.01 for broadband ultrasound attenuation (BUA) and r=-0.67, P < 0.01 for velocity of sound (VOS)]. Similarly, there were inverse correlations between QUS and cumulative dose of prednisone (r=-0.48, P < 0.05 for BUA and r=-0.50, P < 0.01 for VOS, respectively). Similar results were obtained when BUA and VOS were adjusted for height. Conclusions. Disease duration and cumulative dose of prednisone in children with polyarticular JIA are risk factors of stunted growth and decreased QUS values of bone quality.