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Summary: Distal radius (wrist) fracture (DRF) in women over age 50 years is an early sign of bone fragility. Women with a recent DRF compared to women without DRF demonstrated lower bone strength, muscle density, and strength, but no difference in dual-energy x-ray absorptiometry (DXA) measures, suggesting DXA alone may not be a sufficient predictor for DRF risk. Introduction: The objective of this study was to investigate differences in bone and muscle properties between women with and without a recent DRF. Methods: One hundred sixty-six postmenopausal women (50-78 years) were recruited. Participants were excluded if they had taken bone-altering medications in the past 6 months or had medical conditions that severely affected daily living or the upper extremity. Seventy-seven age-matched women with a fracture in the past 6-24 months (Fx, n = 32) and without fracture (NFx, n = 45) were measured for bone and muscle properties using the nondominant (NFx) or non-fractured limb (Fx). Peripheral quantitative computed tomography (pQCT) was used to estimate bone strength in compression (BSI) at the distal radius and tibia, bone strength in torsion (SSIp) at the shaft sites, muscle density, and area at the forearm and lower leg. Areal bone mineral density at the ultradistal forearm, spine, and femoral neck was measured by DXA. Grip strength and the 30-s chair stand test were used as estimates of upper and lower extremity muscle strength. Limb-specific between-group differences were compared using multivariate analysis of variance (MANOVA). Results: There was a significant group difference ( p < 0.05) for the forearm and lower leg, with the Fx group demonstrating 16 and 19 % lower BSI, 3 and 6 % lower muscle density, and 20 and 21 % lower muscle strength at the upper and lower extremities, respectively. There were no differences between groups for DXA measures. Conclusions: Women with recent DRF had lower pQCT-derived estimated bone strength at the distal radius and tibia and lower muscle density and strength at both extremities. [ABSTRACT FROM AUTHOR]

Summary: Limited prospective evidence exists regarding bone microarchitectural deterioration. We report annual changes in trabecular and cortical bone microarchitecture at the distal radius and tibia in postmenopausal women. Lost trabeculae with corresponding increase in trabecular thickness at the radius and thinning tibial cortex indicated trabecularization of the cortex at both sites. Introduction: Osteoporosis is characterized by low bone mass and the deterioration of bone microarchitecture. However, limited prospective evidence exists regarding bone microarchitectural changes in postmenopausal women: a population prone to sustaining osteoporotic fractures. Our primary objective was to characterize the annual change in bone area, density, and microarchitecture at the distal radius and distal tibia in postmenopausal women. Methods: Distal radius and tibia were measured using high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and 1 year later in 51 women (mean age ± SD, 77 ± 7 years) randomly sampled from the Saskatoon cohort of the Canadian Multicentre Osteoporosis Study (CaM os). We used repeated measures analysis of variance (ANOVA) with Bonferroni adjustment for multiple comparisons to characterize the mean annual change in total density, cortical perimeter, trabecular and cortical bone area, density, content, and microarchitecture. Significant changes were accepted at P < 0.05. Results: At the distal radius in women without bone-altering drugs, total density (−1.7 %) and trabecular number (−6.4 %) decreased, while trabecular thickness (+6.0 %), separation (+8.6 %), and heterogeneity (+12.1 %) increased. At their distal tibia, cortical area (−4.5 %), density (−1.9 %), content (−6.3 %), and thickness (−4.4 %) decreased, while trabecular area (+0.4 %) increased. Conclusions: The observed loss of trabeculae with concomitant increase in trabecular size at the distal radius and the declined cortical thickness, density, and content at the distal tibia indicated a site-specific trabecularization of the cortical bone in postmenopausal women. [ABSTRACT FROM AUTHOR]

Summary: Evidence of measurement precision, annual changes and monitoring time interval is essential when designing and interpreting longitudinal studies. Despite the precise measures, small annual changes in bone properties led to monitoring time intervals (MTIs) of 2-6 years in peripheral quantitative computed tomography (pQCT)-derived radial and tibial bone area, density, and estimated strength in postmenopausal women. Introduction: The purpose of the study was to determine the precision error, annual change, and MTI in bone density, area, and strength parameters in postmenopausal women. Methods: Postmenopausal women ( n = 114) from the Saskatoon cohort of the Canadian Multicentre Osteoporosis Study had annual pQCT scans of the distal and shaft sites of the radius and tibia for 2 years. Median annualized rates of percent change and the MTI were calculated for bone density, area, and strength parameters. Root mean squared coefficients of variation (CV%) were calculated from duplicate scans in a random subgroup of 35 postmenopausal women. Results: CV% ranged from 1.4 to 6.1 % at the radius and 0.7 to 2.1 % at the tibia. MTIs for the distal radius were 3 years for total bone density (ToD) and 4 years for total bone cross sectional area (ToA), trabecular area, and bone strength index. At the diaphyseal radius, MTI was 3 years for ToA, 5 years for cortical density, and 6 years for polar stress strain index (SSI). Similarly, MTI for total and trabecular density was 3 years at the distal tibia. At the diaphyseal tibia, MTI for ToA was 3 years and SSI 4 years. Conclusion: MTI for longitudinal studies in older postmenopausal women should be at least 2-6 years at the radius and tibia, with specific monitoring of the total and trabecular area, total density, and bone strength at the radius and total and trabecular density, total area, and bone strength at the tibia. [ABSTRACT FROM AUTHOR]