We assessed the role of low aBMD and impaired architecture—assessed by an HR-pQCTsystem—in a case-control study of postmenopausal women with fractures. Vertebral and nonvertebral frac-tures are associated with low volumetric BMD and architectural alterations of trabecular and cortical bone,independent of aBMD assessed by DXA.

Introduction:​ Alterations of bone architecture and low BMD both contribute to skeletal fragility, but thecontribution of cortical and trabecular architecture, independently ofareal BMD (aBMD), to the risk offracture in postmenopausal women has not been thoroughly evaluated. We assessed the role of impairedarchitecture and low BMD in postmenopausal women with fractures.

Materials and Methods:​ A matched case-control study in women from the OFELY cohort was performedafter 13 years of follow-up. One hundred one women (mean, 73.7 ± 8 years) who sustained a fragility fractureduring the follow-up of the study were age-matched with one control who never had a fracture. Density andarchitecture at the distal radius and tibia were measured with high-resolution pQCT (HR-pQCT) using anXTreme CT (Scanco Medical AG, Bassersdorf, Switzerland). aBMD at the total hip and ultradistal radius wasmeasured by DXA.

Results:​ There were 80 peripheral fractures in 72 women, 44 vertebral fractures in 34 women, and both typesof fractures in 5 women over the 14 years of follow-up. At the distal radius,women with fractures had lowervolumetric total (D tot) and trabecular (D trab) BMDs, BV/TV, cortical thickness (Cort Th), trabecularnumber (TbN), and trabecular thickness (TbTh) and higher trabecular separation (TbSp) and distribution oftrabecular separation (TbSpSd) than controls without fractures. In a logistic model, each SD decrease ofvolumetric total and trabecular densities was associated with a significantly increased risk of fracture at bothsites (ORs ranged from 2.00 to 2.47). After adjusting for aBMD measured by DXA at the ultradistal radius,differences between cases and controls remained significant for D trab, and there was a similar trend for TbN,TbSp, and TbSpSd, with adjusted ORs ranging from 1.32 to 1.50. At the distaltibia, before and after adjustingfor total hip aBMD, differences between cases and controls remained significant for D tot, D trab, Cort Th,and TbTh, with adjusted ORs ranging from 1.80 to 2.09.

Conclusions:​ In postmenopausal women, vertebral and nonvertebral fractures are associated with low volu-metric BMD and architectural alterations of trabecular and cortical bonethat can be assessed noninvasivelyand that are partially independent of aBMD assessed by DXA.