Vertebral fracture risk and alendronate effects on osteoporosis assessed by a computed tomography-based nonlinear finite element method

Computed tomography-based nonlinear finite element method (CT/FEM) can accurately predict vertebral compressive strength ex vivo and this method is clinically available in vivo. This study aimed to assess vertebral fracture risk and alendronate effects on osteoporosis in vivo using CT/FEM. Vertebral strength in 123 postmenopausal women was analyzed and the discriminatory power for vertebral fracture was assessed cross-sectionally. Alendronate effects were also prospectively assessed in 33 patients with postmenopausal osteoporosis who were treated with alendronate at a dose of 5 mg/day for 18 months. CT/FEM had higher discriminatory power for vertebral fracture than areal bone mineral density (BMD) and volumetric BMD and detected alendronate effects at 3 months. Marked bone density increases were noted in juxtacortical areas compared to inner trabecular areas. CT/FEM was useful for assessing vertebral fracture risk and therapeutic effects on osteoporosis.     

Bone Microarchitecture Assessed by HR‐pQCT as Predictor of Fracture Risk in Postmenopausal Women: The OFELY Study

Several cross‐sectional studies have shown that impairment of bone microarchitecture contributes to skeletal fragility. The aim of this study was to prospectively investigate the prediction of fracture (Fx) by bone microarchitecture assessed by high‐resolution peripheral computed tomography (HR‐ pQCT) in postmenopausal women. We measured microarchitecture at the distal radius and tibia with HR‐pQCT in the OFELY study, in addition to areal BMD with dual‐energy X‐ray absorptiometry (DXA) in 589 women, mean ± SD age 68 ± 9 years. During a median [IQ] 9.4 [1.0] years of follow‐up, 135 women sustained an incident fragility Fx, including 81 women with a major osteoporotic Fx (MOP Fx). After adjustment for age, women who sustained Fx had significantly lower total and trabecular volumetric densities (vBMD) at both sites, cortical parameters (area and thickness at the radius, vBMD at the tibia), trabecular number (Tb.N), connectivity density (Conn.D), stiffness, and estimated failure load at both sites, compared with control women. After adjustment for age, current smoking, falls, prior Fx, use of osteoporosis‐related drugs, and total hip BMD, each quartile decrease of several baseline values of bone microarchitecture at the radius was associated with significant change of the risk of Fx (HR of 1.39 for Tb.BMD [p = 0.001], 1.32 for Tb.N [p = 0.01], 0.76 for Tb.Sp.SD [p = 0.01], 1.49 [p = 0.01] for Conn.D, and 1.27 for stiffness [p = 0.02]). At the tibia, the association remained significant for stiffness and failure load in the multivariate model for all fragility Fx and for Tt.BMD, stiffness, and failure load for MOP Fx. We conclude that impairment of bone microarchitecture—essentially in the trabecular compartment of the radius—predict the occurrence of incident fracture in postmenopausal women. This assessment may play an important role in identifying women at high risk of fracture who could not be adequately detected by BMD measurement alone, to benefit from a therapeutic intervention. © 2017 American Society for Bone and Mineral Research.     

Assessment of vertebral fracture risk and therapeutic effects of alendronate in postmenopausal women using a quantitative computed tomography-based nonlinear finite element method

Summary  A QCT-based nonlinear FEM was used to assess vertebral strength and mechanical parameters in postmenopausal women. It had higher discriminatory power for vertebral fracture than aBMD and vBMD. Alendronate effects were detected at 3 months, and marked bone density increases were noted in juxta-cortical areas compared to inner trabecular areas. Introduction  QCT-based finite element method (QCT/FEM) can predict vertebral compressive strength ex vivo. This study aimed to assess vertebral fracture risk and alendronate effects on osteoporosis in vivo using QCT/FEM. Methods  Vertebral strength in 104 postmenopausal women was analyzed, and the discriminatory power for vertebral fracture was assessed cross-sectionally. Alendronate effects were also prospectively assessed in 33 patients with postmenopausal osteoporosis who were treated with alendronate for 1 year. Results  On the age and body weight adjusted logistic regression, vertebral strength had stronger discriminatory power for vertebral fracture (OR per SD change: 6.71) than areal BMD and volumetric BMD. The optimal point for the vertebral fracture threshold was 1.95 kN with 75.9% sensitivity and 78.7% specificity. At 3 months, vertebral strength significantly increased by 10.2% from baseline. The minimum principal strain distribution showed that the area of high fracture risk decreased. At 1 year, the density of the inner cancellous bone increased by 8.3%, while the density of the juxta-cortical area increased by 13.6%. Conclusions  QCT/FEM had higher discriminatory power for vertebral fracture than BMD and detected alendronate effects at 3 months. Alendronate altered density distributions, thereby decreasing the area with a high fracture risk, resulting in increased vertebral strength.     

Individual trabeculae segmentation (ITS)–based morphological analysis of high‐resolution peripheral quantitative computed tomography images detects abnormal trabecular plate and rod microarchitecture in premenopausal women with idiopathic osteoporosis

Idiopathic osteoporosis (IOP) in premenopausal women is a poorly understood entity in which otherwise healthy women have low‐trauma fracture or very low bone mineral density (BMD). In this study, we applied individual trabeculae segmentation (ITS)–based morphological analysis to high‐resolution peripheral quantitative computed tomography (HR‐pQCT) images of the distal radius and distal tibia to gain greater insight into skeletal microarchitecture in premenopausal women with IOP. HR‐pQCT scans were performed for 26 normal control individuals and 31 women with IOP. A cubic subvolume was extracted from the trabecular bone compartment and subjected to ITS‐based analysis. Three Young's moduli and three shear moduli were calculated by micro–finite element (µFE) analysis. ITS‐based morphological analysis of HR‐pQCT images detected significantly decreased trabecular plate and rod bone volume fraction and number, decreased axial bone volume fraction in the longitudinal axis, increased rod length, and decreased rod‐to‐rod, plate‐to‐rod, and plate‐to‐plate junction densities at the distal radius and distal tibia in women with IOP. However, trabecular plate and rod thickness did not differ. A more rod‐like trabecular microstructure was found in the distal radius, but not in the distal tibia. Most ITS measurements contributed significantly to the elastic moduli of trabecular bone independent of bone volume fraction (BV/TV). At a fixed BV/TV, plate‐like trabeculae contributed positively to the mechanical properties of trabecular bone. The results suggest that ITS‐based morphological analysis of HR‐pQCT images is a sensitive and promising clinical tool for the investigation of trabecular bone microstructure in human studies of osteoporosis. © 2010 American Society for Bone and Mineral Research     

Microarchitectural deterioration of cortical and trabecular bone: Differing effects of denosumab and alendronate

The intensity of bone remodeling is a critical determinant of the decay of cortical and trabecular microstructure after menopause. Denosumab suppresses remodeling more than alendronate, leading to greater gains in areal bone mineral density (aBMD). These greater gains may reflect differing effects of each drug on bone microarchitecture and strength. In a phase 2 double‐blind pilot study, 247 postmenopausal women were randomized to denosumab (60 mg subcutaneous 6 monthly), alendronate (70 mg oral weekly), or placebo for 12 months. All received daily calcium and vitamin D. Morphologic changes were assessed using high‐resolution peripheral quantitative computed tomography (HR‐pQCT) at the distal radius and distal tibia and QCT at the distal radius. Denosumab decreased serum C‐telopeptide more rapidly and markedly than alendronate. In the placebo arm, total, cortical, and trabecular BMD and cortical thickness decreased (?2.1% to ?0.8%) at the distal radius after 12 months. Alendronate prevented the decline (?0.6% to 2.4%, p = .051 to <.001 versus placebo), whereas denosumab prevented the decline or improved these variables (0.3% to 3.4%, p < .001 versus placebo). Changes in total and cortical BMD were greater with denosumab than with alendronate (p ≤ .024). Similar changes in these parameters were observed at the tibia. The polar moment of inertia also increased more in the denosumab than alendronate or placebo groups (p < .001). Adverse events did not differ by group. These data suggest that structural decay owing to bone remodeling and progression of bone fragility may be prevented more effectively with denosumab. © 2010 American Society for Bone and Mineral Research     

Baseline BMD and Bone Loss at Distal Radius Measured by Peripheral Quantitative Computed Tomography in Peri- and Postmenopausal Hong Kong Chinese Women

The current study was designed to investigate the rate of bone loss in distal radius and its association with baseline volumetric bone mineral density (BMD) and years since menopause (YSM) in peri- and postmenopausal women using precise and multislice peripheral quantitative computed tomography (pQCT; Densiscan 2000). Two hundred and five healthy Hong Kong Chinese perimenopausal (n = 26) and postmenopausal (n = 179) women within 10 years of the onset of menopause were recruited. Anthropometric parameters and menstrual status were also measured. The linear regression model derived from the baseline volumetric BMD revealed a significant and slightly better correlation with YSM than age, with a YSM-related annual decline of 2.56%, 1.82% and 0.65% in trabecular BMD (tBMD), integral BMD (iBMD) and cortical BMD (cBMD), respectively. Follow-up measurements after a time interval of 12 months showed that the rate of bone loss was higher than the annual decline in BMD calculated from the baseline BMD, with decreases of 2.89%, 2.16% 0.91% in tBMD, iBMD and cBMD, respectively. Baseline BMD was associated with age or YSM (r ranges from −0.283 to −0.502; p<0.001 in all cases), but no relationship was found between annual rate of bone loss and age or YSM. The rate of bone loss did not correlate with baseline volumetric BMD values or YSM after dividing the subjects into fast bone losers (with annual tBMD loss ≥3%), normal bone losers (with annual tBMD loss ≥ 1% but <3%) or slow bone losers (with annual tBMD loss <1%). The rate of bone loss was greater in both trabecular and cortical bone of postmenopausal women within the first 3 menopausal years but was only significant in the iBMD as compared with perimenopausal and postmenopausal women over 7 years after onset of menopause. The percentage distribution of slow and fast bone losers was not found to be associated with YSM. As a total of only 4 fracture cases were documented, the study could not provide conclusive information on whether perimenopausal and early postmenopausal baseline volumetric BMD or rate of bone loss determines the development of osteoporosis or fracture occurrence. Received: 12 November 2001 / Accepted: 18 July 2002     

Changes in trabecular and cortical bone microarchitecture at peripheral sites associated with 18?months of teriparatide therapy in postmenopausal women with osteoporosis

Summary  

We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to monitor changes in bone microarchitecture and strength at the distal radius and tibia associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis. Despite treatment-associated declines in total and cortical BMD, trabecular thinning and reduced trabecular bone volume, bone strength did not change significantly from baseline.     

Evaluation of trabecular microarchitecture in nonosteoporotic postmenopausal women with and without fracture

This study compared microscopic magnetic resonance imaging (μMRI) parameters of trabecular microarchitecture between postmenopausal women with and without fracture who have normal or osteopenic bone mineral density (BMD) on dual-energy X-ray absorptiometry (DXA). It included 36 postmenopausal white women 50 years of age and older with normal or osteopenic BMD (T-scores better than -2.5 at the lumbar spine, proximal femur, and one-third radius on DXA). Eighteen women had a history of low-energy fracture, whereas 18 women had no history of fracture and served as an age, race, and ultradistal radius BMD-matched control group. A three-dimensional fast large-angle spin-echo (FLASE) sequence with 137 μm × 137 μm × 400 μm resolution was performed through the nondominant wrist of all 36 women using the same 1.5T scanner. The high-resolution images were used to measure trabecular bone volume fraction, trabecular thickness, surface-to-curve ratio, and erosion index. Wilcoxon signed-rank tests were used to compare differences in BMD and μMRI parameters between postmenopausal women with and without fracture. Post-menopausal women with fracture had significantly lower (p < 0.05) trabecular bone volume fraction and surface-to-curve ratio and significantly higher (p < 0.05) erosion index than postmenopausal women without fracture. There was no significant difference between postmenopausal women with and without fracture in trabecular thickness (p = 0.80) and BMD of the spine (p = 0.21), proximal femur (p = 0.19), one-third radius (p = 0.47), and ultradistal radius (p = 0.90). Postmenopausal women with normal or osteopenic BMD who had a history of low-energy fracture had significantly different (p < 0.05) μMRI parameters than an age, race, and ultradistal radius BMD-matched control group of postmenopausal women with no history of fracture. Our study suggests that μMRI can be used to identify individuals without a DXA-based diagnosis of osteoporosis who have impaired trabecular microarchitecture and thus a heretofore-unappreciated elevated fracture risk.     

Trabecular structure quantified with the MRI-based virtual bone biopsy in postmenopausal women contributes to vertebral deformity burden independent of areal vertebral BMD.

In postmenopausal women with a wide range of vertebral deformities, MRI-based structural measures of topology and scale at the distal radius are shown to account for as much as 30% of vertebral deformity, independent of integral vertebral BMD. INTRODUCTION: Trabecular bone architecture has been postulated to contribute to overall bone strength independent of vertebral BMD measured by DXA. However, there has thus far been only sparse in vivo evidence to support this hypothesis. MATERIALS AND METHODS: Postmenopausal women, 60-80 yr of age, were screened by DXA, and those with T-scores at either the hip or spine falling within the range of -2.5 +/- 1.0 were studied with the MRI-based virtual bone biopsy, along with heel broadband ultrasound absorption and pQCT of the tibia. The data from 98 subjects meeting the enrollment criteria were subjected to microMRI at the distal tibia and radius, and measures of topology and scale of the trabecular bone network were computed. A spinal deformity index (SDI) was obtained from morphometric measurements in midline sagittal MR images of the thoracic and lumbar spine to evaluate associations between structure and deformity burden. RESULTS: A number of structural indices obtained at the distal radius were correlated with the SDI. Among these were the topological surface density (a measure of trabecular plates) and trabecular bone volume fraction, which were inversely correlated with SDI (p < 0.0001). Combinations of two structural parameters accounted for up to 30% of the variation in SDI (p < 0.0001) independent of spinal BMD, which was not significantly correlated. pQCT trabecular BMD was also weakly associated, whereas broadband ultrasound absorption was not. No significant association between SDI and structural indices were found at the tibia. CONCLUSIONS: Structural measures at the distal radius obtained in vivo by microMRI explained a significant portion of the variation in total spinal deformity burden in postmenopausal women independent of areal BMD.     

Estimation of the Architectural Properties of Cortical Bone Using Peripheral Quantitative Computed Tomography

We assessed the volumetric bone mineral density (vBMD) and cross-sectional architecture of cortical bone at the distal radius by peripheral quantitative computed tomography (pQCT). The volumetric bone mineral density [integral bone mineral density (BMDi), trabecular bone mineral density (BMDt) and cortical with subcortical bone mineral density (BMDsc)] and the architectural parameters [cortical bone area (CBA), cortical thickness (C-th), moment of inertia (Im) and polar moment of inertia (Ip)] were measured in 115 healthy premenopausal women, 48 osteoporotic postmenopausal women and 78 age-matched healthy postmenopausal women. Age-matched healthy women had higher values of vBMD and architectural parameters at the distal radius than osteoporotic women. Premenopausal women had higher values of vBMD and architectural parameters at the distal radius than postmenopausal women. The differences in the architectural parameters between age-matched healthy women and osteoporotic women were more pronounced when only the high density area (threshold 0.70 cm^–1) was included. However, the differences in architectural parameters between premenopausal women and postmenopausal women were significant using even the lowest threshold value of 0.50 cm^–1 in the calculation. Receiver operating characteristic (ROC) curves were constructed and the areas under the curves calculated to evaluate the discriminating power of vBMD and architectural parameters. Comparison of the different ROC curves showed no statistical significance. In conclusion, our results suggest that both the density and mass distribution of the radius were clearly different between the healthy women and osteoporotic women. The differences in architectural parameters were more useful for studying the pathopysiology of osteoporosis than for contributing to the diagnosis. Determination of the cross-sectional mass distribution of bone combined with BMD should offer more information than BMD alone in the study of the pathophysiology of osteoporosis. Received: 22 December 1998 / Accepted: 2 June 1999     

Trabecular Bone Architecture in the Distal Radius Using Magnetic Resonance Imaging in Subjects with Fractures of the Proximal Femur

To determine whether magnetic resonance (MR)-derived measures of trabecular bone architecture in the distal radius are predictive for prevalent hip fractures, 20 subjects with hip fractures and 19 age-matched postmenopausal controls were studied. Bone mineral density (BMD) measures at the hip (dual-energy X-ray absorptiometry, DXA) and the distal radius (peripheral quantitative computed tomography, pQCT) were also obtained. We compared the MR-based structural measures derived in the radius with those in the calcaneus of the same patients. In the radius, images were acquired at an in-plane resolution of 156 μm and a slice thickness of 0.5 mm. Stereologic measures such as the apparent trabecular thickness (app. Tb.Th), fractional trabecular bone volume (app. BV/TV), trabecular spacing (app. Tb.Sp) and trabecular number (app. Tb.N) were derived from the images. Measures of app. Tb.Sp and app. Tb.N in the distal radius showed significant (p<0.05) differences between the two groups, as did hip BMD measures. However, radial trabecular BMD measures showed only a marginal difference (p= 0.05). Receiver operating curve analysis was used to determine the diagnostic efficacy of BMD, structural measures and a combination of the two. The area under the curve (AUC) for total hip BMD was 0.73, and for radial trabecular BMD was 0.69. AUC for most of the measures of trabecular bone structure at the distal radius was lower than for hip BMD measures; however, AUC for app. Tb.N at the radius was 0.69, comparable to trabecular BMD using pQCT. The AUC for combined BMD (hip) and structure measures was higher (0.87) when radius and calcaneus structure was included. Measures of trabecular architecture derived from MR images combined with BMD measures improve the discrimination between subjects with hip fractures and normal age-matched controls. Received: 22 December 1998 / Accepted: 12 February 1999     

Effects of Odanacatib on the Radius and Tibia of Postmenopausal Women: Improvements in Bone Geometry,Microarchitecture, and Estimated Bone Strength

The cathepsin K inhibitor odanacatib (ODN), currently in phase 3 development for postmenopausal osteoporosis, has a novel mechanism of action that reduces bone resorption while maintaining bone formation. In phase 2 studies, odanacatib increased areal bone mineral density (aBMD) at the lumbar spine and total hip progressively over 5 years. To determine the effects of ODN on cortical and trabecular bone and estimate changes in bone strength, we conducted a randomized, double‐blind, placebo‐controlled trial, using both quantitative computed tomography (QCT) and high‐resolution peripheral (HR‐p)QCT. In previously published results, odanacatib was superior to placebo with respect to increases in trabecular volumetric BMD (vBMD) and estimated compressive strength at the spine, and integral and trabecular vBMD and estimated strength at the hip. Here, we report the results of HR‐pQCT assessment. A total of 214 postmenopausal women (mean age 64.0 ± 6.8 years and baseline lumbar spine T‐score –1.81 ± 0.83) were randomized to oral ODN 50 mg or placebo, weekly for 2 years. With ODN, significant increases from baseline in total vBMD occurred at the distal radius and tibia. Treatment differences from placebo were also significant (3.84% and 2.63% for radius and tibia, respectively). At both sites, significant differences from placebo were also found in trabecular vBMD, cortical vBMD, cortical thickness, cortical area, and strength (failure load) estimated using finite element analysis of HR‐pQCT scans (treatment differences at radius and tibia = 2.64% and 2.66%). At the distal radius, odanacatib significantly improved trabecular thickness and bone volume/total volume (BV/TV) versus placebo. At a more proximal radial site, odanacatib attenuated the increase in cortical porosity found with placebo (treatment difference = –7.7%, p = 0.066). At the distal tibia, odanacatib significantly improved trabecular number, separation, and BV/TV versus placebo. Safety and tolerability were similar between treatment groups. In conclusion, odanacatib increased cortical and trabecular density, cortical thickness, aspects of trabecular microarchitecture, and estimated strength at the distal radius and distal tibia compared with placebo. © 2014 American Society for Bone and Mineral Research     

The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women

Summary  Few studies have investigated the long-term effects of potassium intake on BMD. In a cohort of 266 elderly women, we found that baseline potassium intake as reflected by 24-hour urine potassium excretion had positive association with BMD measured at 1 and/or 5 years later, suggesting a role of dietary potassium on osteoporosis prevention. Introduction  High dietary potassium intake has been suggested to be beneficial for bone structure, but few studies have investigated the long-term effects of potassium intake on BMD in elderly women. We examined the relationship between potassium intake as reflected by 24-hour urine potassium excretion and bone density in a cohort of elderly women. Methods  The study subjects were 266 elderly postmenopausal women aged 70–80 years. Twenty-four-hour urinary potassium excretion was determined at baseline. At one year hip DXA BMD was measured, at 5 years hip and total body DXA BMD and distal radius and tibia pQCT vBMD were measured. The effects of potassium were evaluated by ANCOVA according to the quartile of baseline urinary potassium excretion. Results  After adjustment for confounding factors, subjects in the highest quartile of urinary potassium excretion had significantly higher total hip BMD at 1 (5%) and 5 years (6%), and significantly higher total body BMD (4%) and 4% distal tibia total (7%) and trabecular vBMD (11%) at 5 years than those in the lowest quartile. Conclusions  Potassium intake shows positive association with bone density in elderly women, suggesting that increasing consumption of food rich in potassium may play a role in osteoporosis prevention.     

Alterations of cortical and trabecular architecture are associated with fractures in postmenopausal women, partially independent of decreased BMD measured by DXA: the OFELY study.

We assessed the role of low aBMD and impaired architecture-assessed by an HR-pQCT system-in a case-control study of postmenopausal women with fractures. Vertebral and nonvertebral fractures 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 the contribution of cortical and trabecular architecture, independently of areal BMD (aBMD), to the risk of fracture in postmenopausal women has not been thoroughly evaluated. We assessed the role of impaired architecture and low BMD in postmenopausal women with fractures. MATERIALS AND METHODS: A matched case-control study in women from the OFELY cohort was performed after 13 years of follow-up. One hundred one women (mean, 73.7+/-8 years) who sustained a fragility fracture during the follow-up of the study were age-matched with one control who never had a fracture. Density and architecture at the distal radius and tibia were measured with high-resolution pQCT (HR-pQCT) using an XTreme CT (Scanco Medical AG, Bassersdorf, Switzerland). aBMD at the total hip and ultradistal radius was measured by DXA. RESULTS: There were 80 peripheral fractures in 72 women, 44 vertebral fractures in 34 women, and both types of fractures in 5 women over the 14 years of follow-up. At the distal radius, women with fractures had lower volumetric total (D tot) and trabecular (D trab) BMDs, BV/TV, cortical thickness (Cort Th), trabecular number (TbN), and trabecular thickness (TbTh) and higher trabecular separation (TbSp) and distribution of trabecular separation (TbSpSd) than controls without fractures. In a logistic model, each SD decrease of volumetric total and trabecular densities was associated with a significantly increased risk of fracture at both sites (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 distal tibia, before and after adjusting for 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 volumetric BMD and architectural alterations of trabecular and cortical bone that can be assessed noninvasively and that are partially independent of aBMD assessed by DXA.     

Forearm BMD as measured by peripheral quantitative computed tomography (pQCT) in a German reference population

Low bone mass as estimated by decreased bone mineral density (BMD) is an established predictor of osteoporotic fractures. One of the latest developments in bone densitometry is peripheral quantitative computed tomography (pQCT) of the forearm. In Germany, the CT bone scanner XCT 900 has already been widely used; however, interpretation of measurements with respect to osteoporosis risk assessment can be improved by better defined and validated reference data. In the present study, this device was used to measure BMD at the distal radius in a well-defined healthy population of 179 German adults (91 men, 88 women) aged 20–79 years. In vivo precision was 1.67% for trabecular and 0.81% for total BMD measurements. Peak values of trabecular and total BMD were observed at the ages 40–50 years in women and 30–40 years in men. Beyond these ages, both trabecular and total BMD showed a linear decline with age, decreasing by 0.85% and 1.08% per year in women and by 0.59% and 0.54% in men, respectively. Measures of BMD were not influenced by weight, height or body mass index (BMI). In both sexes, trabecular and total radial BMD showed a positive and significant correlation with femoral BMD measures obtained by dual X-ray absorptiometry (DXA). Weaker correlations were observed with DXA measures of the lumbar spine. Compared with the 95% reference range provided by the manufacturer, the distribution of age- and sex-specific values of trabecular BMD of the distal radius was shifted to lower values by up to 1 standard deviation. Thus, 17% (30 of 179) of our apparently healthy population had BMD values falling short of the suggested lower reference limit. On the other hand, the distribution of total BMD values was shifted to higher values by up to 2 standard deviations in the younger age groups. We conclude that pQCT of the radius is a precise method for measuring BMD, but that its use for osteoporosis risk assessment crucially depends on both well-defined reference data and the results of prospective studies.     

Bone density and geometric properties of the distal radius in displaced and undisplaced Colles' fractures: Quantitative CT in 70 women

We examined cortical and trabecular bone density and geometric properties of the unfractured distal radius in 70 women with recent Colles' fractures, using multilayer peripheral quantitative computed tomography (pQCT). We found that cortical volumetric density, cortical area and mean cortical thickness were lower in the displaced than in the undisplaced fractures, suggesting that the cross-sectional volumetric density and geometric properties of cortical bone may be essential in determining the severity of a Colles' fracture. We also compared lumbar spine and femoral neck bone mineral density (BMD) and the occurrence of osteoporosis in the displaced and undisplaced fracture groups and found no significant difference, which suggests that displacement of a Colles' fracture is not associated with general osteoporosis.     

Abnormal microarchitecture and reduced stiffness at the radius and tibia in postmenopausal women with fractures

Measurement of areal bone mineral density (aBMD) by dual‐energy x‐ray absorptiometry (DXA) has been shown to predict fracture risk. High‐resolution peripheral quantitative computed tomography (HR‐pQCT) yields additional information about volumetric BMD (vBMD), microarchitecture, and strength that may increase understanding of fracture susceptibility. Women with (n = 68) and without (n = 101) a history of postmenopausal fragility fracture had aBMD measured by DXA and trabecular and cortical vBMD and trabecular microarchitecture of the radius and tibia measured by HR‐pQCT. Finite‐element analysis (FEA) of HR‐pQCT scans was performed to estimate bone stiffness. DXA T‐scores were similar in women with and without fracture at the spine, hip, and one‐third radius but lower in patients with fracture at the ultradistal radius (p < .01). At the radius fracture, patients had lower total density, cortical thickness, trabecular density, number, thickness, higher trabecular separation and network heterogeneity (p < .0001 to .04). At the tibia, total, cortical, and trabecular density and cortical and trabecular thickness were lower in fracture patients (p < .0001 to .03). The differences between groups were greater at the radius than at the tibia for inner trabecular density, number, trabecular separation, and network heterogeneity (p < .01 to .05). Stiffness was reduced in fracture patients, more markedly at the radius (41% to 44%) than at the tibia (15% to 20%). Women with fractures had reduced vBMD, microarchitectural deterioration, and decreased strength. These differences were more prominent at the radius than at the tibia. HR‐pQCT and FEA measurements of peripheral sites are associated with fracture prevalence and may increase understanding of the role of microarchitectural deterioration in fracture susceptibility. © 2010 American Society for Bone and Mineral Research.     

Bone density and geometric properties of the distal radius in displaced and undisplaced Colles' fractures: quantitative CT in 70 women

We examined cortical and trabecular bone density and geometric properties of the unfractured distal radius in 70 women with recent Colles' fractures, using multilayer peripheral quantitative computed tomography (pQCT). We found that cortical volumetric density, cortical area and mean cortical thickness were lower in the displaced than in the undisplaced fractures, suggesting that the cross-sectional volumetric density and geometric properties of cortical bone may be essential in determining the severity of a Colles' fracture. We also compared lumbar spine and femoral neck bone mineral density (BMD) and the occurrence of osteoporosis in the displaced and undisplaced fracture groups and found no significant difference, which suggests that displacement of a Colles' fracture is not associated with general osteoporosis.     

Effect of alendronate on bone mineral density and bone turnover markers in post-gastrectomy osteoporotic patients

Alendronate decreases the urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX; about 45% at 3 months) and serum levels of alkaline phosphatase (ALP; about 27% at 24 months), leading to an increase in lumbar spine bone mineral density (BMD; about 9% at 24 months) in postmenopausal Japanese women with osteoporosis. However, the effectiveness of oral bisphosphonates on osteoporosis remains to be established in patients who have undergone a gastrectomy. The objective of the present case series study was to examine the effect of alendronate on BMD and bone turnover markers in post-gastrectomy osteoporotic patients. Sixteen patients (3 men and 13 postmenopausal women) with osteoporosis, who had undergone a gastrectomy (mean age: 69.1 years), were recruited in our outpatient clinic. All the patients were treated with alendronate (5 mg daily or 35 mg weekly) for 24 months. The effects of alendronate on lumbar spine (women) or total hip (men) BMD and urinary NTX and serum ALP levels were examined. A total or partial gastrectomy had been performed for eight patients each. The mean duration after surgery was 16.0 years. With alendronate therapy, urinary NTX levels significantly decreased at 3 months (−27.0%). Serum ALP levels decreased (−12.1%) and lumbar spine BMD increased (+5.2%), but total hip BMD did not significantly change (+0.6%) at 24 months. No severe adverse events were observed, and alendronate therapy was well tolerated. These results suggest that alendronate mildly increases lumbar spine BMD by mildly reducing bone turnover in osteoporotic patients after a gastrectomy.     

Bone density and geometric properties of the distal radius in displaced and undisplaced Colles' fractures: Quantitative CT in 70 women

We examined cortical and trabecular bone density and geometric properties of the unfractured distal radius in 70 women with recent Colles' fractures, using multilayer peripheral quantitative computed tomography (pQCT). We found that cortical volumetric density, cortical area and mean cortical thickness were lower in the displaced than in the undisplaced fractures, suggesting that the cross-sectional volumetric density and geometric properties of cortical bone may be essential in determining the severity of a Colles' fracture. We also compared lumbar spine and femoral neck bone mineral density (BMD) and the occurrence of osteoporosis in the displaced and undisplaced fracture groups and found no significant difference, which suggests that displacement of a Colles' fracture is not associated with general osteoporosis.