BONE-MINERAL DENSITY AND TURNOVER IN CHILDREN WITH SYSTEMIC JUVENILE CHRONIC ARTHRITIS

Objective. To assess bone mineral status in a group of children with s ystemic type juvenile chronic arthritis (JCA), which places them at hi gh risk to develop osteoporosis. Methods. Bone mineral density (BMD) w as measured in 17 children aged 6-18 yrs (mean 14.9 +/- 4.5) with syst emic JCA and in 18 matched controls by dual energy x-ray absorptiometr y. Bone turnover was determined by quantitative bone scintigraphy, usi ng quantitative single photon emission computed tomography based on sk eletal uptake of methylene diphosphonates (MDP uptake). Serum concentr ations of minerals, osteocalcin, and bone alkaline phosphatase were de termined. Nutrient intake was assessed by a 24 hour dietary recall. Re sults. Patients with systemic JCA who received corticosteroid therapy had significantly reduced BMD in both the lumbar spine (p < 0.05) and the femoral neck (p < 0.05) compared to controls, whereas BMD values o f the non-steroid systemic JCA patients were not different from contro ls. Bone turnover measurement by MDP uptake showed no difference betwe en patients with JCA and controls. Levels of calcium, phosphorus, alka line phosphatase. and osteocalcin were within normal limits in all pat ients. Conclusion. Patients with systemic JCA receiving longterm stero id treatment may develop a significant decrease in BMD. The normal MDP uptake values together with normal osteocalcin levels that we observe d in our patients indicate that their disease is not associated with e nhancement of bone turnover rates. These observations might have thera peutic implications for prevention and management of osteoporosis in J CA.