Noninvasive Assessment of Skeletal Microstructure and Estimated Bone Strength in XXXX .

@entity1 @entity261 @entity170 @entity79
In @entity261 , areal @entity79 ( @entity79 ) by dual-energy X-ray absorptiometry (DXA) is above average, and skeletal indices by bone biopsy are abnormal. We used high-resolution peripheral quantitative computed tomography (HRpQCT) and finite element analyses (FEA) to further investigate skeletal microstructure and estimated bone strength. We studied 60 @entity261 subjects on conventional therapy using DXA, HRpQCT, and FEA of the distal radius and tibia compared with normative controls from the Canadian Multicentre @entity170 Study. In @entity261 @entity1 and @entity1 , areal @entity79 was above average at the lumbar spine and hip sites by DXA; radial @entity79 was also above average in @entity261 @entity1 . Using HRpQCT, cortical volumetric @entity79 was increased in the @entity261 cohort compared with controls at both the radius and tibia. Cortical porosity was reduced at both sites in pre- and postmenopausal @entity1 and at the tibia in young @entity1 with a downward trend at the radius in @entity1 . At the tibia, trabecular number was increased in premenopausal @entity1 and @entity1 and trabecular thickness was lower in @entity1 . Ultimate stress and failure load at both sites for the @entity261 subjects were similar to controls. Using a linear regression model, at both radius and tibia, each increment in age decreased ultimate stress and failure load, whereas each increment in duration of @entity261 increased these same indices. These results provide additional evidence for the critical role of parathyroid hormone in regulating skeletal microstructure. Longer disease duration may mitigate the adverse effects of age on estimated bone strength in @entity261 .    2015 American Society for Bone and Mineral Research.
