ESTIMATION OF CENTRAL OSTEOPENIA IN CHILDREN WITH CHRONIC POLYARTHRITIS TREATED WITH GLUCOCORTICOIDS

Study objective. To investigate the degree and determinants of osteope nia in juvenile chronic polyarthritis. Design. Retrospective case-cont rol study of central bone mineral density. Setting. Rheumatism Foundat ion Hospital and Kuopio University Hospital, Finland. Subjects. A samp le of 43 girls aged 7 to 19 with juvenile chronic polyarthritis treate d with systemic glucocorticoids and a control sample of 44 healthy gir ls matched for age. Main outcome measures. Bone mineral density and bo ne size (width) measured by dual-energy x-ray absorptiometry and bone volumetric density calculated as an approximation of true bone density at both the lumbar spine and femoral neck. Results. The girls with ju venile chronic arthritis had reduced bone mineral density, bone size, and bone volumetric density at both the lumbar spine and femoral neck (statistically significant findings, P = .022 for the bone size of the femoral neck and P < .001 for the other parameters). At the spine, th e mean bone mineral density was 80%, the mean bone size 89%, and the m ean bone volumetric density 89% of the values in the control group. At the femoral neck, the values were 78%, 93%, and 83%, respectively. Th e groups were matched for age, but the girls with arthritis were small er and lighter. In the juvenile arthritis group, the femoral bone mine ral density and bone volumetric density and the spinal bone width corr elated negatively with the mean glucocorticoid dose. Conclusion. Axial bone mineral density is clearly reduced in severe juvenile polyarthri tis and is mediated by both decreased bone volumetric density and dimi nished growth.