Bone mineral metabolism in juvenile chronic arthritis: the influence of steroids

Calciotropic hormone assays and bone mineral density (BMD) evaluations were carried out on a group of 36 children affected with juvenile chronic arthritis (JCA) (13 with pauciarticular, 8 with polyarticular and 15 with systemic onset subtype) and in a matched control group. The plasma levels of calcium, phosphate and alkaline phosphatase were normal in all the groups. Basal 25-OH D plasma levels were significantly decreased both in the polyarticular and in the systemic groups; the latter showed a further decrease after 1 year. There was a significant decrease in both the basal and the 1-year plasma levels of 1-25-OH D only in the systemic group. The BMD was decreased in the systemic group alone and the percentage increase after 1 year was significantly inferior to that in the other groups and in the controls. There was a clear relationship between the decrease in hormones and the cumulative dose of steroids administered, as well as between the BMD decrease and the physical activity of the patients (according to Steinbrocker's classification).