Bone mineral loss at the proximal femur in acute spinal cord injury

Summary

This study used quantitative computed tomography to assess changes in bone mineral at the proximal femur after acute spinal cord injury (SCI). Individuals with acute SCI experienced a marked loss of bone mineral from a combination of trabecular and endocortical resorption. Targeted therapeutic interventions are thus warranted in this population.

Introduction

SCI is associated with a rapid loss of bone mineral and an increased rate of fragility fracture. Some 10 to 20 % of these fractures occur at the proximal femur. The purpose of this study was to quantify changes to bone mineral, geometry, and measures of strength at the proximal femur in acute SCI.

Methods

Quantitative computed tomography analysis was performed on 13 subjects with acute SCI at serial time points separated by a mean of 3.5 months (range, 2.6–4.8 months). Changes in bone mineral content (BMC) and volumetric bone mineral density (vBMD) were quantified for integral, trabecular, and cortical bone at the femoral neck, trochanteric, and total proximal femur regions. Changes in bone volumes, cross-sectional areas, and surrogate measures of compressive and bending strength were also determined.

Results

During the acute period of SCI, subjects experienced a 2.7–3.3 %/month reduction in integral BMC (p?<?0.001) and a 2.5–3.1 %/month reduction in integral vBMD (p?<?0.001). Trabecular BMC decreased by 3.1–4.7 %/month (p?<?0.001) and trabecular vBMD by 2.8–4.4 %/month (p?<?0.001). A 3.9–4.0 %/month reduction was observed for cortical BMC (p?<?0.001), while the reduction in cortical vBMD was noticeably lower (0.8–1.0 %/month; p?≤?0.01). Changes in bone volume and cross-sectional area suggested that cortical bone loss occurred primarily through endosteal resorption. Declines in bone mineral were associated with a 4.9–5.9 %/month reduction in surrogate measures of strength.

Conclusions

These data highlight the need for therapeutic interventions in this population that target both trabecular and endocortical bone mineral preservation.     

Obesity alters cortical and trabecular bone density and geometry in women

Summary

The goal in this study was to determine the relationship between body mass index and trabecular and cortical bone using quantitative computed tomography. A higher body mass index (BMI) was positively associated with trabecular and cortical bone parameters, and serum parathyroid hormone, and negatively associated with cortical volumetric bone mineral density (vBMD) and serum 25-hydroxy-vitamin D. When BMI is greater than 35 kg/m², adiposity affects vBMD and may explain the higher fracture risk in this population without low BMD.

Introduction

The influence of adult obesity on the trabecular and cortical bone, geometry, and strength has not been fully addressed. The goal in this study was to determine the relationship between body mass index and trabecular and cortical bone mass and geometry, over a wide range of body weights.

Methods

We examined 211 women (25–71 years; BMI 18–57 kg/m²) who were classified into three categories of BMI (kg/m²) including normal-weight (BMI?<?25), overweight and obese-class I (BMI 25–35) and obese-class II–III (BMI?>?35), and also by menopausal status. Volumetric bone mineral density (mg/cm³), trabecular, and cortical components as well as geometric characteristics at the 4%, 38%, and 66% from the distal tibia were measured by peripheral quantitative computed tomography, and serum was analyzed for parathyroid hormone (PTH) and 25-hydroxy-vitamin D (25OHD).

Results

Higher BMI was associated with greater values of trabecular bone and cortical BMC and area and PTH (r?>?0.39, p?<?0.001), but lower cortical vBMD and 25OHD (r?>??0.27, p?<?0.001). When controlling for lower leg muscle area, fat area was inversely associated with cortical vBMD (r?=??0.16, p?<?0.05). Premenopausal obese women with both higher BMI and PTH had lower cortical vBMD (r?<??0.40, p?<?0.001). While age is a predictor for most bone variables, fat mass explains more variance for vBMD, and lean mass and 25OHD explain greater variance in geometric and strength indices (p?<?0.05).

Conclusions

Severe obesity (BMI?>?35) increases trabecular vBMD and in the presence of a higher PTH is associated with a lower cortical vBMD without compromising bone geometry and strength. Whether or not a lower cortical vBMD in obesity influences fracture risk over time needs to be further explored.     

Impaired trabecular and cortical microarchitecture in daughters of women with osteoporotic fracture: the MODAM study

Summary

We investigated the familial resemblance of bone microarchitecture parameters between postmenopausal mothers with fragility fracture and their premenopausal daughters using high-resolution peripheral quantitative computed tomography (HR-pQCT). We found that daughters of women with fracture have lower total volumetric bone mineral density (vBMD), thinner cortices, and impaired trabecular microarchitecture at the distal radius and tibia, compared to controls.

Introduction

Familial resemblance of areal bone mineral density (aBMD) in mothers and daughters has been widely studied, but not its morphological basis, including microarchitecture.

Methods

We compared aBMD, vBMD, bone size, and bone microarchitecture at the distal radius and tibia assessed by HR-pQCT in mothers and their premenopausal daughters. We included 115 women aged 43?±?8 years whose mothers had sustained a fragility fracture and 206 women aged 39?±?9 years whose mothers had never sustained a fragility fracture.

Results

Women whose mothers had fracture had significantly (p?<?0.05) lower aBMD at the lumbar spine, total hip, femoral neck, mid-distal radius, and ultradistal radius compared to controls. In similar multivariable models, women whose mothers had a fracture had lower total vBMD at the distal radius (?5 %, 0.3 standard deviation [SD]; p?<?0.005) and distal tibia (?7 %, 0.4 SD; p?<?0.005). They also had lower cortical thickness and area at the distal radius (?5 %, 0.3 SD and ?4 %, 0.2 SD, respectively; p?<?0.005) and at the distal tibia (?6 %, 0.3 SD and ?4 %, 0.3SD, respectively; p?<?0.005). Trabecular vBMD was lower at the distal radius (?5 %, 0.3 SD; p?<?0.05) and tibia (?8 %, 0.4 SD; p?<?0.005), with a more spaced and heterogeneous trabecular network (4 and 7 % at the radius and 5 and 9 %, at the tibia, p?<?0.05, for Tb.Sp and Tb.Sp.SD, respectively).

Conclusion

Premenopausal daughters of women who had sustained fragility fracture have lower total and trabecular vBMD, thinner cortices, as well as impaired trabecular microarchitecture at the distal radius and tibia, compared with premenopausal daughters of women without fracture.     

Fracture risk in children with a forearm injury is associated with volumetric bone density and cortical area (by peripheral QCT) and areal bone density (by DXA)

Summary

Children who sustain a forearm fracture when injured have lower bone density throughout their skeleton, and have a smaller cortical area and a lower strength index in their radius. Odds ratios per SD decrease in bone characteristics measured by peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) were similar (1.28 to 1.41).

Introduction

Forearm fractures are common in children. Bone strength is affected by bone mineral density (BMD) and bone geometry, including cross-sectional dimensions and distribution of mineral. Our objective was to identify bone characteristics that differed between children who sustained a forearm fracture compared to those who did not fracture when injured.

Methods

Children (5–16 years) with a forearm fracture (cases, n?=?224) and injured controls without fracture (n?=?200) were enrolled 28?±?8 days following injury. Peripheral QCT scans of the radius (4% and 20% sites) were obtained to measure volumetric BMD (vBMD) of total, trabecular and cortical bone compartments, and bone geometry (area, cortical thickness, and strength strain index [SSI]). DXA scans (forearm, spine, and hip) were obtained to measure areal BMD (aBMD) and bone area. Receiver operating characteristic (ROC) analyses were used to assess screening performance of bone measurements.

Results

At the 4% pQCT site, total vBMD, but not trabecular vBMD or bone area, was lower (?3.4%; p?=?0.02) in cases than controls. At the 20% site, cases had lower cortical vBMD (?0.9%), cortical area (?2.8%), and SSI (?4.6%) (p?<?0.05). aBMD, but not bone area, at the 1/3 radius, spine, and hip were 2.7–3.3% lower for cases (p?<?0.01). Odds ratios per 1 SD decrease in bone measures (1.28–1.41) and areas under the ROC curves (0.56–0.59) were similar for all bone measures.

Conclusions

Low vBMD, aBMD, cortical area, and SSI of the distal radius were associated with an increased fracture risk. Interventions to increase these characteristics are needed to help reduce forearm fracture occurrence.     

Distribution of bone density and cortical thickness in the proximal femur and their association with hip fracture in postmenopausal women: a quantitative computed tomography study

Summary

The quantitative computed tomography (QCT) scans in an individually matched case–control study of women with hip fracture were analysed. There were widespread deficits in the femoral volumetric bone mineral density (vBMD) and cortical thickness of cases, and cortical vBMD and thickness discriminated hip fracture independently of BMD by dual-energy X-ray absorptiometry (DXA).

Introduction

Acknowledging the limitations of QCT associated with partial volume effects, we used QCT in an individually matched case–control study of women with hip fracture to better understand its structural basis.

Methods

Fifty postmenopausal women (55–89 years) who had sustained hip fractures due to low-energy trauma underwent QCT scans of the contralateral hip within 3 months of the fracture. For each case, postmenopausal women, matched by age (±5 years), weight (±5 kg) and height (±5 cm), were recruited as controls. We quantified cortical, trabecular and integral vBMD and apparent cortical thickness (AppCtTh) in four quadrants of cross-sections along the length of the femoral head (FH), femoral neck (FN), intertrochanter and trochanter and examined their association with hip fracture.

Results

Women with hip or intracapsular (IC) fracture had significantly (p?<?0.05) lower vBMD and AppCtTh than the controls in the majority of cross-sections and quadrants of the proximal femur, and both cortical and trabecular compartments are involved. Cortical vBMD and AppCtTh in the FH and FN were associated with hip and IC fractures independent of hip areal BMD (aBMD). The combination of AppCtTh and trabecular or integral vBMD discriminated hip fracture, whereas the combination of FH and FN AppCtTh discriminated IC fracture significantly (p?<?0.05) better than the hip aBMD.

Conclusion

Deficits in vBMD and AppCtTh in cases were widespread in the proximal femur, and cortical vBMD and AppCtTh discriminated hip fracture independently of aBMD by DXA.     

The association of serum 25-hydroxyvitamin D with indicators of bone quality in men of Caucasian and African ancestry

Summary

We examined the association of serum 25-hydroxyvitamin D [25(OH)D] with indices of bone quality in older men. Positive associations for 25(OH)D and bone mineral density, content, cortical thickness, and axial and polar strength strain indices were observed among Caucasians; however, among men of African descent findings were either null or negative.

Introduction

There are limited data on serum 25(OH)D and bone measures in men of African ancestry. To better understand racial differences in vitamin D status and bone health, a cross-sectional study among 446 Caucasian men in the US and 496 men of African ancestry in Tobago (age ?? 65?years) was conducted.

Methods

Serum 25(OH)D (liquid chromatography and tandem mass spectrometry) was measured, and peripheral quantitative computed tomography scans were administered. Bone measures estimated included trabecular and cortical volumetric bone mineral density (vBMD), bone mineral content (BMC), bone geometry (cross-sectional area and cortical thickness), and polar and axial strength strain indices (SSIp and SSIx).

Results

Men of African ancestry had higher 25(OH)D than Caucasians (34.7 vs. 27.6?ng/ml, p < 0.01). Among Caucasians, 25(OH)D was positively (p trend < 0.05) associated with cortical vBMD, total BMC, cortical thickness, SSIp, and SSIx at the distal radius after adjustment for potential confounders. Similar patterns were observed at the distal tibia. In contrast, in men of African ancestry, there was an inverse association (p trend < 0.05) between 25(OH)D and the cross-sectional area, and SSIx. Race modified (p for interaction < 0.05) the association between 25(OH)D and total BMC, cross-sectional area, SSIp, SSIx, and trabecular vBMD of the radius. In men of African ancestry, there was evidence of a threshold effect (at approximately 18?ng/ml) for 25(OH)D on tibial total BMC and cortical thickness.

Conclusions

More studies are needed to better comprehend these race differences for 25(OH)D and bone density, geometry, and indices of bone strength.     

The Deleterious Effect of Bariatric Surgery on Cortical and Trabecular Bone Density in the Femurs of Non-obese, Type 2 Diabetic Goto-Kakizaki Rats

Background

The effects of type 2 diabetes on bone mass and microstructure are not clear. The aim of this study was to evaluate bone microstructural properties and volumetric bone mineral density (vBMD) in type 2 diabetic Goto-Kakizaki non-obese rats after gastrojejunal bypass and their relationship with hormonal parameters.

Methods

We designed an experimental study in Goto-Kakizaki rats with and without gastrojejunal bypass, performing densitometric and microstructural studies of the distal femur using X-ray computed microtomography (micro-CT). Levels of insulin, glucagon, leptin, and glucagon-like peptide-1 (GLP-1) were also determined.

Results

We observed reduced cortical (1,488.92?±?98.2 vs. 1,727.92?±?133.45?mg/cm³, p?=?0.028) and trabecular (180.8?±?9 vs. 261.23?±?45.54?mg/cm³, p?=?0.036) vBMD in operated rats. Bone volume fraction (BV/TV) and trabecular connectivity were reduced in operated rats, while there was a reduction in cortical thickness and an increase in rod-like trabeculae at the expense of plate-like trabeculae. Leptin was reduced (1,042?±?549 vs. 2,447?±?1,035?pg/ml, p?=?0.05) and GLP-1 increased (1.62?±?0.32 vs. 0.96?±?0.1?ng/ml, p?=?0.008) but only leptin showed a significant association with vBMD

Conclusions

In type 2 diabetic Goto-Kakizaki rats, gastrojejunal bypass produces a reduction in cortical and trabecular bone mineral density and a deterioration in bone quality that could be explained, in part, by the reduction in leptin levels.     

Effect of parathyroidectomy versus risedronate on volumetric bone mineral density and bone geometry at the tibia in postmenopausal women with primary hyperparathyroidism

The objective of the study was to evaluate the effect of parathyroidectomy (PTX) versus 35 mg once-weekly (ow) risedronate administration on volumetric bone mineral density (vBMD) and bone geometry at the tibia in postmenopausal women with primary hyperparathyroidism (PHPT). Our open-label prospective observational study included 32 postmenopausal women with PHPT as the study group: 16 underwent PTX and 16 were treated with 35 mg ow risedronate for 2 years. We assessed areal BMD (aBMD) by DXA, and vBMD and bone mineral content (BMC) (cortical and trabecular area) by peripheral quantitative computed tomography (pQCT) at the tibia at baseline and at 2 years. Risedronate did not result in any significant change on vBMD and structural pQCT indices. PTX resulted in significant increase in trabecular (trab) BMC (6.44 %) and vBMD (4.64 %), with percent increase being significantly higher than risedronate (p < 0.05). At cortical sites, there was no significant change following PTX. However, the percent change in cortical (cort) vBMD was higher following PTX versus risedronate (0.39 % vs. ?0.26 %, p < 0.05). In conclusion, in postmenopausal women with PHPT, PTX is superior to ow risedronate, in terms of improvement of trabecular mineralization and vBMD at the tibia, whereas the effect at cortical sites is less pronounced.     

Cortical and trabecular bone at the radius and tibia in male and female adolescents with Down syndrome: a peripheral quantitative computed tomography (pQCT) study

Summary

We aimed to describe the structure and strength of the tibia and radius of adolescents with Down syndrome. We observed that despite higher levels of volumetric bone mineral density in determined skeletal sites, they are at higher risk of developing osteoporotic fractures in the future due to their lower bone strength indexes.

Introduction

The aims of the study were to describe the cortical and trabecular volumetric bone mineral density (vBMD), bone mineral content (BMC), area, and bone strength in adolescents with Down syndrome (DS) and to compare them with adolescents without disabilities.

Methods

Thirty adolescents (11 girls) with DS and 28 without disabilities (10 girls) participated in the study. Peripheral quantitative computed tomography measurements were taken at proximal and distal sites of the tibia and radius. Values of total, trabecular, and cortical BMC; vBMD; and area were obtained of each scan. Cortical thickness and endosteal and periosteal circumferences were also measured, and different bone strength indexes were calculated. Student’s t tests were applied between groups.

Results

The DS group showed greater vBMD at distal radius, BMC at proximal radius, and total and cortical vBMD at proximal tibia. The non-DS group showed higher total and trabecular area at the distal radius and total, cortical, and trabecular BMC and area at distal tibia. Higher values of periosteal and endosteal circumference and bone strength were also found in non-DS group.

Conclusions

From these results, it can be believed that even with higher vBMD in determined skeletal sites, adolescents with DS are at higher risk of suffering bone fractures due to an increased fragility by lower resistance to load bending or torsion.     

Determinants of bone strength and fracture incidence in adult Finns: Cardiovascular Risk in Young Finns Study (the GENDI pQCT study)

Summary

Peripheral bone strength and fracture risk were studied in young adult Finns. Peripheral bone measures were associated with risk factors of osteoporosis in young adults and discriminated between those with and without low-energy fractures. In men, trabecular bone loss at peripheral bone sites starts before the age of 40 years.

Purpose

This is a cross-sectional study of the determinants of bone strength and fracture risk in young Finns using peripheral quantitative computed tomography (pQCT) and quantitative ultrasound (QUS).

Methods

pQCT scans were performed in 1,884 subjects at distal and shaft sites of non-dominant radius and left tibia, and QUS measures (n?=?1,415) at the left calcaneus. Lifestyle factors and medical conditions affecting bone health were assessed with questionnaires.

Results

In men, the youngest age cohort had the lowest trabecular volumetric bone mineral density (vBMD) at radius and tibia (difference between the youngest and the oldest, 4.4% and 5.6%, respectively, P?<?0.001) and lowest speed of ultrasound at the calcaneus (difference 0.5%, P?=?0.016). In women, bone traits did not differ by age groups. When sexes were pooled, underweight (relative risk (RR)?=?2.95, P?<?0.001), excess alcohol intake (1.52, P?=?0.036), smoking (1.29, P?=?0.025), Crohn’s disease or inflammatory bowel syndrome (2.43, P?=?0.016), epilepsy (2.54, P?=?0.011), use of corticosteroids (2.01, P?<?0.001) and inactivity (1.34, P?=?0.045) increased the risk of low trabecular vBMD. RRs for low-energy fractures were excess alcohol intake (2.58, P?=?<0.001), anorexia (3.74, P?=?0.041) and hypogonadism (2.08, P?=?0.015). Same risk factors predicted BMD and fractures in both sexes. Trabecular bone mineral content, vBMD and bone strength index showed greatest differences (4–9%; P?<?0.05) between those with and without low-energy fractures.

Conclusions

Peripheral QCT traits are associated with common risk factors of osteoporosis in young Finns and discriminate between those with and without low-energy fractures. In men, trabecular bone loss at peripheral bone sites starts before the age of 40 years.     

Birth weight is more important for peak bone mineral content than for bone density: the PEAK-25 study of 1,061 young adult women

Summary

Lower birth weight has a negative association with adult BMC and body composition in young adult Swedish women.

Introduction

The aim of this study was to evaluate the influence of birth weight on peak bone mass and body composition in a cohort of 25-year-old women.

Methods

One thousand sixty-one women participated in this cross-sectional population-based study using dual energy X-ray absorptiometry (DXA) to assess bone mineral content (BMC), bone mineral density (BMD), and body composition (total body (TB), femoral neck (FN), total hip (TH), lumbar spine L1–L4 (LS), and lean and fat mass). Birth weight data was available for 1,047 women and was categorized into tertiles of low (≤3,180 g), intermediate (3,181–3,620 g), and high (≥3,621 g) birth weight.

Results

Significant correlations were observed between birth weight and TB-BMC (r?=?0.159, p?<?0.001), FN-BMC (r?=?0.096, p?<?0.001), TH-BMC (r?=?0.102, p?=?0.001), LS-BMC (r?=?0.095, p?=?0.002), and lean mass (r?=?0.215, p?<?0.001). No correlation was observed between birth weight and BMD. The estimated magnitude of effect was equivalent to a 0.3–0.5 SD difference in BMC for every 1 kg difference in birth weight (151 g (TB); 0.22 g (FN); 1.5 g (TH), 2.5 kg TB lean mass). The strongest correlations between birth weight and BMC occurred in women with lowest birth weights, although excluding women who weighed <2,500 g at birth, and the correlation remained significant although slightly weaker.

Conclusions

Women with lower birth weight have lower BMC and less lean and fat mass at the age of 25, independent of current body weight. Lower birth weight has a greater negative influence on bone mass than the positive influence of higher birth weight.     

Site-specific differential effects of once-yearly zoledronic acid on the hip assessed with quantitative computed tomography: results from the HORIZON Pivotal Fracture Trial

Summary

We used new approaches to the analysis of diagnostic scans to detect changes in bone density in different regions of the hip after 3 years of treatment with the zoledronic acid. We showed that the drug significantly increases hip bone density compared to placebo at regions where hip fractures usually occur.

Introduction

This study aims to identify whether treatment with zoledronic acid exerts site-specific differential effects on volumetric bone mineral density (vBMD) at the hip.

Methods

We analysed quantitative computed tomography scans of the hip obtained at baseline and 36 months in 179 women participating in the HORIZON Pivotal Fracture Trial. Cortical, trabecular and integral BMDs were determined at three main regions of interest—the femoral neck (FN), trochanter (TR) and total hip (TH)—and several sub-regions of interest, namely the proximal, middle, distal, anterior, posterior, inferomedial and superolateral FN, and the middle and distal TR.

Results

Volumetric BMD increased significantly (p?<?0.05) from baseline with zoledronic acid compared to placebo. Trabecular vBMD increased as follows: FN, 5.4 %; FN sub-regions, 6.0 % (proximal), 4.4 % (middle), 5.6 % (distal), 7.5 % (anterior), 7.0 % (superolateral) and 5.4 % (posterior); TR, 6.5 % and TH, 5.7 %. Cortical vBMD increased as follows: FN sub-regions, 5.0 % (proximal FN) and 2.3 % (anterior); TR, 4.6 %; middle TR, 2.7 % and TH, 3.8 %.

Conclusions

The effects on vBMD of annual infusion of 5 mg of zoledronic acid are site-specific and dominated by trabecular changes.     

Relative impact of neuromuscular and cardiovascular factors on bone strength index of the hemiparetic distal radius epiphysis among individuals with chronic stroke

Summary

The objective of this study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. The results showed that grip strength is the most predominant predictor of the bone strength index.

Introduction

The pupose of the study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors.

Methods

Sixty-five chronic stroke survivors and 34 healthy control subjects underwent scanning of the distal radius epiphyseal site on both sides using peripheral quantitative computed tomography to measure trabecular volumetric bone mineral density (vBMD) (mg/cm³), total vBMD (mg/cm³), total area (mm²), and compressive bone strength index (cBSI) (g²/cm⁴). Various indicators of neuromuscular (grip strength, spasticity) and cardiovascular function (vascular elasticity, oxygen consumption during 6-min walk test) were evaluated.

Results

Analysis of variance revealed a significant main effect of side (p?p?p?p?>?0.05). Sex-specific analysis yielded similar results. Multiple regression analyses revealed that the cBSI of the hemiparetic distal radius epiphysis had a stronger association with neuromuscular factors than cardiovascular factors. Overall, grip strength was the strongest determinant of the cBSI of the hemiparetic distal radius epiphysis (p?Conclusions Muscle weakness is the most predominant determinant of cBSI in the hemiparetic distal radius epiphysis among chronic stroke patients. Future studies should investigate the efficacy of different muscle-strengthening strategies in enhancing bone strength of this skeletal site in the chronic stroke population.     

Association of volumetric bone mineral density with abdominal aortic calcification in African ancestry men

Summary

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors.

Introduction

The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence.

Methods

Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia.

Results

Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P?<?0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45–0.92).

Conclusions

Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification.     

Changes in trabecular bone density in incident pediatric Crohn’s disease: a comparison of imaging methods

Summary

This study of changes in dual energy x-ray absorptiometry (DXA) spine BMD following diagnosis and treatment for childhood Crohn’s disease demonstrated that changes in conventional posteroanterior BMD results were confounded by impaired growth, and suggested that lateral spine measurements and strategies to estimate volumetric BMD were more sensitive to disease and treatment effects.

Introduction

We previously reported significant increases in peripheral quantitative CT (pQCT) measures of trabecular volumetric bone mineral density (vBMD) following diagnosis and treatment of pediatric Crohn’s disease (CD). The objective of this study was to compare pQCT trabecular vBMD and three DXA measures of spine BMD in this cohort: (1) conventional posteroanterior BMD (PA-BMD), (2) PA-BMD adjusted for height Z (PA-BMD_HtZ), and (3) width-adjusted volumetric BMD (WA-BMD) estimated from PA and lateral scans.

Methods

Spine DXA [lumbar (L1–4) for posteroanterior and L3 for lateral] and tibia pQCT scans were obtained in 65 CD subjects (ages 7–18 years) at diagnosis and 12 months later. BMD results were converted to sex, race, and age-specific Z-scores based on reference data in >650 children (ages 5–21 years). Multivariable linear regression models identified factors associated with BMD Z-scores.

Results

At CD diagnosis, all BMD Z-scores were lower compared with the reference children (all p values <0.01). The pQCT vBMD Z-scores (?1.46?±?1.30) were lower compared with DXA PA-BMD (?0.75?±?0.98), PA-BMD_HtZ (?0.53?±?0.87), and WA-BMD (?0.61?±?1.10) among CD participants. Only PA-BMD Z-scores were correlated with height Z-scores at baseline (R?=?0.47, p?<?0.0001). pQCT and WA-BMD Z-scores increased significantly over 12 months to ?1.04?±?1.26 and ?0.20?±?1.14, respectively. Changes in all four BMD Z-scores were positively associated with changes in height Z-scores (p?<?0.05). Glucocorticoid doses were inversely associated with changes in WA-BMD (p?<?0.01) only.

Conclusions

Conventional and height Z-score-adjusted PA DXA methods did not demonstrate the significant increases in trabecular vBMD noted on pQCT and WA-BMD scans. WA-BMD captured glucocorticoid effects, potentially due to isolation of the vertebral body on the lateral projection. Future studies are needed to identify the BMD measure that provides greatest fracture discrimination in CD.     

Sport-specific association between exercise loading and the density, geometry, and microstructure of weight-bearing bone in young adult men

Summary

In this population-based study of 24-year-old men, we have investigated the association between sport-specific exercise loading and different bone parameters. We reveal that the association between exercise loading and bone parameters is sport-specific, indicating that nonspecific resistance exercise does not impact bone density, geometry, or microstructure in young men.

Introduction

In this cross-sectional study, the association between nonspecific resistive exercise and areal and volumetric bone density, bone geometry, or bone microstructure was investigated in young adult men.

Methods

A total of 184 male athletes, 24.0?±?0.6 years of age (mean?±?SD), representing nonspecific resistive exercise and soccer (proportion of recreational athletes, 93.4 and 7.7 %, respectively), and 177 nonathletic age-matched controls were measured with dual-energy X-ray absorptiometry. Radius and tibia were measured by peripheral quantitative computed tomography (pQCT) at the diaphysis and by three-dimensional pQCT at the metaphysis.

Results

Men in the nonspecific resistive exercise group had higher grip strength(9.1 % or 0.4 SD) and higher lean mass(5.6 % or 0.5 SD) than those in the nonathletic group(p?<?0.01 and p?<?0.001, respectively). However, men who participated in nonspecific resistive exercise did not have higher bone density or a more favorable bone microstructure or geometry than their nonathletic referents. In contrast, men playing soccer had higher areal bone mineral density (aBMD) at the femoral neck (19.5 % or 1.2 SD) and lumbar spine (12.6 % or 1.0 SD), as well as larger cortical cross-sectional area (16.4 % or 1.1 SD) and higher trabecular bone volume fraction (14.5 % or 0.9 SD), as a result of increased trabecular number (8.7 % or 0.6 SD) and thickness (5.7 % or 0.4 SD) at the tibia than men in the nonathletic group(p?<?0.001).

Conclusions

Weight-bearing exercise with impacts from varying directions (playing soccer) is associated with aBMD and volumetric BMD, cortical bone geometry, as well as trabecular microstructure of weight-bearing bone. Nonspecific recreational resistance exercise does not appear to be a strong determinant of bone density, geometry, or microstructure in young adult men.     

Effect of once-yearly zoledronic acid on the spine and hip as measured by quantitative computed tomography: results of the HORIZON Pivotal Fracture Trial

Summary

Changes in bone mineral density and bone strength following treatment with zoledronic acid (ZOL) were measured by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA). ZOL treatment increased spine and hip BMD vs placebo, assessed by QCT and DXA. Changes in trabecular bone resulted in increased bone strength.

Introduction

To investigate bone mineral density (BMD) changes in trabecular and cortical bone, estimated by quantitative computed analysis (QCT) or dual-energy X-ray absorptiometry (DXA), and whether zoledronic acid 5 mg (ZOL) affects bone strength.

Methods

In 233 women from a randomized, controlled trial of once-yearly ZOL, lumbar spine, total hip, femoral neck, and trochanter were assessed by DXA and QCT (baseline, Month 36). Mean percentage changes from baseline and between-treatment differences (ZOL vs placebo, t-test) were evaluated.

Results

Mean between-treatment differences for lumbar spine BMD were significant by DXA (7.0%, p?<?0.01) and QCT (5.7%, p?<?0.0001). Between-treatment differences were significant for trabecular spine (p?=?0.0017) [non-parametric test], trabecular trochanter (10.7%, p?<?0.0001), total hip (10.8%, p?<?0.0001), and compressive strength indices at femoral neck (8.6%, p?=?0.0001), and trochanter (14.1%, p?<?0.0001).

Conclusions

Once-yearly ZOL increased hip and spine BMD vs placebo, assessed by QCT vs DXA. Changes in trabecular bone resulted in increased indices of compressive strength.     

Alterations of bone microstructure and strength in end-stage renal failure

Summary

End-stage renal disease (ESRD) patients have a high risk of fractures. We evaluated bone microstructure and finite-element analysis-estimated strength and stiffness in patients with ESRD by high-resolution peripheral computed tomography. We observed an alteration of cortical and trabecular bone microstructure and of bone strength and stiffness in ESRD patients.

Introduction

Fragility fractures are common in ESRD patients on dialysis. Alterations of bone microstructure contribute to skeletal fragility, independently of areal bone mineral density.

Methods

We compared microstructure and finite-element analysis estimates of strength and stiffness by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 33 ESRD patients on dialysis (17 females and 16 males; mean age, 47.0?±?12.6 years) and 33 age-matched healthy controls.

Results

Dialyzed women had lower radius and tibia cortical density with higher radius cortical porosity and lower tibia cortical thickness, compared to controls. Radius trabecular number was lower with higher heterogeneity of the trabecular network. Male patients displayed only a lower radius cortical density. Radius and tibia cortical thickness correlated negatively with bone-specific alkaline phosphatase (BALP). Microstructure did not correlate with parathyroid hormone (PTH) levels. Cortical porosity correlated positively with “Kidney Disease: Improving Global Outcomes” working group PTH level categories (r?=?0.36, p?<?0.04). BMI correlated positively with trabecular number (r?=?0.4, p?<?0.02) and negatively with trabecular spacing (r?=??0.37, p?<?0.03) and trabecular network heterogeneity (r?=??0.4, p?<?0.02). Biomechanics positively correlated with BMI and negatively with BALP.

Conclusion

Cortical and trabecular bone microstructure and calculated bone strength are altered in ESRD patients, predominantly in women. Bone microstructure and biomechanical assessment by HR-pQCT may be of major clinical relevance in the evaluation of bone fragility in ESRD patients.     

Effect of oral monthly ibandronate on bone microarchitecture in women with osteopenia—a randomized placebo-controlled trial

Summary

We have examined the effect of oral monthly ibandronate on distal radius and tibia microarchitecture with high-resolution peripheral quantitative tomography compared with placebo, in women with osteopenia, and found that ibandronate did not significantly affect trabecular bone but improved cortical density and thickness at the tibia.

Methods

We have examined the effect of ibandronate on bone microarchitecture with peripheral high-resolution quantitative computed tomography (HR-pQCT) in a randomized placebo-controlled trial among 148 women with osteopenia. Patients received either oral 150 mg monthly ibandronate or placebo over 24 months. Bone microarchitecture was assessed at baseline, 6, 12, and 24 months, using HR-pQCT at the distal radius and tibia; areal bone mineral density (aBMD) was measured with DXA at the spine, hip, and radius.

Results

At 12 months, there was no significant difference in trabecular bone volume at the radius (the primary end point) between women on ibandronate (10.8?±?2.5%) and placebo (10.5?±?2.9%), p?=?0.25. There was no significant difference in other radius trabecular and cortical microarchitecture parameters at 12 and 24 months. In contrast, at the tibia, cortical vBMD in the ibandronate group was significantly greater than in the placebo group at 6, 12, and 24 months, with better cortical thickness at 6, 12, and 24 months. With ibandronate, aBMD was significantly increased at the hip and spine at 12 and 24 months but at the radius was significantly superior to placebo only at 24 months. Most of the adverse events related to ibandronate were expected with bisphosphonate use, and none of them were serious.

Conclusion

We conclude that 12 months of treatment with ibandronate in women with osteopenia did not affect trabecular bone microarchitecture, but improved cortical vBMD at the tibia at 12 and 24 months, and preserved cortical thickness at the tibia.     

Novel ultrasonic bone densitometry based on two longitudinal waves: significant correlation with pQCT measurement values and age-related changes in trabecular bone density, cortical thickness, and elastic modulus of trabecular bone in a normal Japanese population

Summary

A reference database for trabecular bone density, cortical thickness, and elastic modulus of trabecular bone for a novel ultrasonic bone densitometry system (LD-100) based on two longitudinal waves (fast and slow) was determined over a wide age range in a normal Japanese population.

Introduction

A novel ultrasonic bone densitometry system (LD-100 system) was applied to create a reference database for trabecular bone density (TBD), cortical thickness (CoTh), and elastic modulus of trabecular bone (EMTb) for this device over a wide age range in a normal Japanese population.

Methods

In a comparative study between LD-100 and peripheral quantitative computed tomography (pQCT) systems, 52 individuals were examined by both systems at the same radius simultaneously. To create a reference database, a total of 2,380 healthy subjects (1,179 men, 1,201 women), ages 18–99 years, were examined using the LD-100 system.

Results

Highly significant correlations between the LD-100 and pQCT systems were found in TBD (r?=?0.877, p?<?0.001) and CoTh (r?=?0.723, p?<?0.001). For the reference database, peak values of TBD, CoTh, and EMTb were observed at 30–34 years (255.09 mg/cm³), 20–24 years (5.23 mm), and 20–24 years (4.09 GPa) in men, and at 25–29 years (209.24 mg/cm³), 25–29 years (3.98 mm), and 20–24 years (3.33 GPa) in women, respectively. The TBD fell significantly (p?<?0.05) beginning at 55–59 years in both sexes, with a relatively rapid decrease in women. The CoTh showed a significant decrease beginning at 40–44 years in men and 50–54 years in women. The EMTb showed a significant decrease beginning at 40–44 years in men and 55–59 years in women.

Conclusions

The LD-100 system is a useful bone densitometry device and the database of age-related changes in TBD, CoTh, and EMTb established in this study will provide fundamental data for future studies related to bone status.