Comparison of Bone Mineral Density Measured by Dual X-ray, Axial Dual-energy Photon X-ray Absorptiometry and Laser Absorptiometry of Calcaneus

The objective of this study was to validate the use of bone mineral measurements of the calcaneus bone by dual X-ray and laser (OXL) in a cross-sectional study carried out in an osteoporosis clinic. Measurements of bone mineral density (BMO) at proximal femur and spine were obtained by dualenergy photon X-ray absorptiometry (DEXA). Osteoporosis was defined by a OEXA T-score -2.5 at the femoral neck or lumbar spine. Sensitivity, specificity and kappa statistics for OXL were calculated, assuming the OEXA measurement as the gold-standard. The study included 475 women with a mean age of 54± 11.9 years. 15% had osteoporosis while 39% were osteopenic (-2.5 T-score between -l) at the femoral neck or spine. A significant correlation (p 0.001) was found between BMO values as measured by OXL at femoral neck and OEXA at the lumbar spine. Assuming the same T-score cut-off value for the diagnosis osteoporosis and a modified cut-off value for the diagnosis of osteopenia (-2. 5 T-score 1.5), yields a sensitivity of 83% and a specificity of 74% to 86% for the OXL device. In conclusion, BMO measured at the calcaneal bone by OXL, has a good correlation with that measured by axial OEXA.