Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Meta, Margarita; Lü, Ying; Keyak, Joyce H.; Lang, Thomas

doi:10.1016/j.bone.2005.11.020

Cited by 31 publications

(22 citation statements)

References 37 publications

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“…2) is consistent with previous reports (3,6,17). In theory, larger femoral neck cross-sectional area is thought to be a compensatory change to offset age-related bone loss (10) and should be protective against fracture (9,18). However, larger cross-sectional area of the femoral neck also has been associated with lower BMD (6).…”

Section: Discussionmentioning

confidence: 99%

Fracture Risk Assessment in Older Adults Using a Combination of Selected Quantitative Computed Tomography Bone Measures: A Subanalysis of the Age, Gene/Environment Susceptibility-Reykjavik Study

Rianon¹,

Lang

Siggeirsdóttir

et al. 2014

Journal of Clinical Densitometry

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Bone mineral density (BMD) and geometric bone measures are individually associated with prevalent osteoporotic fractures. Whether an aggregate of these measures would better associate with fractures has not been examined. We examined relationships between self-reported fractures and selected bone measures acquired by quantitative computerized tomography (QCT), a composite bone score, and QCT-acquired dual-energy X-ray absorptiometry–like total femur BMD in 2110 men and 2682 women in the Age, Gene/Environment Susceptibility-Reykjavik Study. The combined bone score was generated by summing gender-specific Z-scores for 4 QCT measures: vertebral trabecular BMD, femur neck cortical thickness, femur neck trabecular BMD, and femur neck minimal cross-sectional area. Except for the latter measure, lower scores for QCT measures, singly and combined, showed positive (p < 0.05) associations with fractures. Results remained the same in stratified models for participants not taking bone-promoting medication. In women on bone-promoting medication, greater femur neck cortical thickness and trabecular BMD were significantly associated with fracture status. However, the association between fracture and combined bone score was not stronger than the associations between fracture and individual measures or total femur BMD. Thus, the selected measures did not all similarly associate with fracture status and did not appear to have an additive effect on fracture status.

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Section: Discussionmentioning

confidence: 99%

Fracture Risk Assessment in Older Adults Using a Combination of Selected Quantitative Computed Tomography Bone Measures: A Subanalysis of the Age, Gene/Environment Susceptibility-Reykjavik Study

Rianon¹,

Lang

Siggeirsdóttir

et al. 2014

Journal of Clinical Densitometry

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“…As recently reviewed by Keaveny and Bouxsein, (31) high-resolution clinical whole body CT scanning of the hip combined with FEA suggests that many candidates for hip fracture might initiate their fracture through localized compressive overload in the cortex as suggested by Carpenter et al (14) and others. (32)(33)(34) When the load on trabeculae in the fall configuration was studied ex vivo with greatly improved resolution using microfinite element analysis by Verhulp et al, (35) the osteoporotic femur also seemed to bear most of its compressive load in the superior cortex. By providing a plausible explanation for an alternative form of local structural failure, caused by elastic instability of this highly loaded cortex, our study highlights the potentially great mechanical importance of femoral neck trabecular bone.…”

mentioning

confidence: 99%

Femoral Neck Trabecular Bone: Loss With Aging and Role in Preventing Fracture

Thomas¹,

Mayhew

Power

et al. 2009

Journal of Bone and Mineral Research

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Hip fracture risk rises 100-to 1000-fold over six decades of age, but only a minor part of this increase is explained by declining BMD. A potentially independent cause of fragility is cortical thinning predisposing to local crushing, in which bone tissue's material disintegrates at the microscopic level when compressed beyond its capacity to maintain integrity. Elastic instability or buckling of a much thinned cortex might alternatively occur under compression. In a buckle, the cortex moves approximately at right angles to the direction of load, thereby distorting its microstructure, eventually to the point of disintegration. By resisting buckling movement, trabecular buttressing would protect the femoral neck cortex against this type of failure but not against crushing. We quantified the effect of aging on trabecular BMD in the femoral neck and assessed its contribution to cortical elastic stability, which determines resistance to buckling. Using CT, we measured ex vivo the distribution of bone in the midfemoral necks of 35 female and 33 male proximal femurs from cases of sudden death in those 20-95 yr of age. We calculated the critical stress s cr , at which the cortex was predicted to buckle locally, from the geometric properties and density of the cortical zone most highly loaded in a sideways fall. Using long-established engineering principles, we estimated the amount by which stability or buckling resistance was increased by the trabecular bone supporting the most stressed cortical sector in each femoral neck. We repeated these measurements and calculations in an age-and sex-matched series of femoral necks donated by women who had suffered intracapsular hip fracture and controls, using histological measurements of cortical thickness to improve accuracy. With normal aging, trabecular BMD declined asymmetrically, fastest in the supero-lateral one-half (in antero-posterior projection) of the trabecular compartment. When viewed axially with respect to the femoral neck, the most rapid loss of trabecular bone occurred in the posterior part of this region (supero-posterior [S-P]), amounting to a 42% reduction in women (34% in men) over five decades of adult age. Because local cortical bone thickness declined comparably, age had no significant effect on the relative contributions of cortical and trabecular bone to elastic stability, and trabecular bone was calculated to contribute 40% (in men) and 43% (in women) to the S-P cortex of its overall elastic stability. Hip fracture cases had reduced elastic stability compared with agematched controls, with a median reduction of 49% or 37%, depending on whether thickness was measured histologically or by CT (pQCT; p < 0.002 for both). This effect was because of reduced cortical thickness and density. Trabecular BMD was similar in hip fracture cases and controls. The capacity of the femur to resist fracture in a sideways fall becomes compromised with normal aging because cortical thickness and trabecular BMD in the most compressed part of the femoral neck both d...

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“…Existence of regional differences of the trabecular parameters at different skeletal sites (Hui et al, 1988;Hildebrand et al, 1999), and regional degradation that may lead to it (Li et al, 2009), were established. Within the proximal femur, trabecular parameters were found to differ among the femoral head inferior to the fovea, superior to the fovea, adjacent to the femoral neck in the lateral aspect of the femoral head and trochanteric region through MRI, CT and microCT and to be correlated with local BMD (Issever et al, 2002;Meta et al, 2006;Sell et al, 2005). Correlation between ultrasonic parameters and BMD by CT was established (Jenson et al, 2006), as well as a relation between quantitative ultrasound results on bone and fracture risk (Marín et al, 2006).…”

Section: Discussionmentioning

confidence: 98%