Growth retardation and bone loss as determinants of axial osteopenia in juvenile chronic arthritis.

The aim of the study was to evaluate the significance of growth retardation and bone loss as determinants of axial osteopenia in children with juvenile oligo- and polyarthritis. Bone mineral density (BMD), bone size (width), and bone volumetric density (BMDvol) were determined by dual x-ray absorptiometry at the lumbar spine and femoral neck in children with juvenile oligoarthritis (n = 36), polyarthritis (n = 75), and a group of healthy children (n = 66). Comparison of measurements showed that children with juvenile polyarthritis had a significantly reduced BMDvol (p < 0.05) and bone size (p < 0.01) at the lumbar spine, resulting in a 10.5% decrease in BMD (p < 0.001). At the femoral neck, the 16% decrease in BMD (p < 0.001) was attributed only to a decrease in BMDvol (p < 0.001). In juvenile oligoarthritis, the development of osteopenia was nonsignificant except at the femur, where the 6.6% decrease of BMD was associated with significant decrease of BMDvol (p < 0.05). The bone loss associated with juvenile chronic arthritis appears to develop with concurrent growth retardation at the spine, but without detectable growth retardation at the femoral neck.