Correlation of bone mineral density measured by peripheral quantitative computed tomography (pQCT) and dual X-ray absorptiometry (DEXA)

This was the first study to correlate the volumetric bone mineral density (BMD) of the distal extremities and area BMD of proximal femur and lumbar spine using two different techniques in Hong Kong Chinese. The volumetric trabecular BMD of distal radius and tibia of non-dominate site was measured by a highly accurate pQCT (Densiscan 2000). DEXA (NORLAND) was used to measures the area density of the lumbar spine L2-L4, the femoral neck, intertrochanteric region, and the Ward's triangle of the proximal femur. Volumetric trabecular BMD of both distal radius and tibia was significantly correlated with the area BMD of spine and proximal femur (r ranged from 0.532 to 0.687, p<0.001). Trabecular BMD of the distal tibia correlated better than that of distal radius with the BMD of both the lumbar spine and proximal femur. Low or no correlation was found between volumetric cortical BMD or the mixed cortical and trabecular BMD in the distal extremities with the area BMD of spine and proximal femur. Findings of this study suggested that the trabecular BMD of the distal extremities, especially the distal tibia as weight-bearing part might be used to predict the BMD and the quality of the lumbar spine and proximal femur.