BONE-MINERAL DISORDERS IN CHILDREN - EVALUATION WITH DUAL X-RAY ABSORPTIOMETRY

PURPOSE: To evaluate the utility of dual x-ray absorptiometry (DXA) in children with bone mineral disorders. MATERIALS AND METHODS: In phase 1, radial DXA was compared with single-energy photon absorptiometry ( SPA) (n = 117). In phase 2, radial and lumbar bone mineral density (BM D) measured with DXA and second metacarpal cortical thickness were com pared (254 examinations, 224 children). RESULTS: For radial BMD, DXA a nd SPA correlated well (r = .956) and SPA-equivalent values could be c alculated from DXA measurements (mean residual error = 0.024 g/cm(2)). After controlling for age, sex, weight, and height, partial correlati ons were very small for lumbar BMD with radial BMD (r = .186) and lumb ar BMD with cortical thickness (r = .158), and slightly better for rad ial BMD with cortical thickness (r = .544). Z scores also correlated p oorly with no meaningful correlation for lumbar BMD with radial BMD (r = .07) CONCLUSION: In children with bone mineral disorders, radial DX A and SPA measurements correlate well. However, lumbar BMD, radial BMD , and cortical thickness correlate poorly and lumbar BMD frequently do es not identify abnormality in patients with abnormal radial BMD. Lumb ar BMD alone is not adequate for evaluation of bone mineral status in these patients.