Femoral neck bone strength estimated by hip structural analysis (HSA) in Swedish Caucasians aged 6-90 years

Canadian adult reference data for body composition, trabecular bone score and advanced hip analysis using DXA

DXA-derived reference data for visceral adipose tissue (VAT) and advanced hip analysis (AHA) parameters spanning the entire adult lifespan are limited. The purpose of this study was to develop age-, site- and sex-specific reference data for dual X-ray absorptiometry (DXA) -derived body composition, trabecular bone score (TBS) and advanced hip analysis (AHA) parameters across the adult lifespan. Adults (N = 908; female: 561 and male: 347) from Calgary and the surrounding area over the age of 20 years participated in this study. Participants received DXA scans of their hip (total hip [TH] and femoral neck [FN]), lumbar spine [LS], forearm [33 % site] and total body (iDXA, GE Lunar, GE Healthcare). Areal bone mineral density (aBMD, g/cm2) was captured at all sites, and body composition variables, including lean mass, fat mass and percent fat, were analyzed from the total body scan. VAT mass was assessed from total body DXA scans. Advanced hip analysis (AHA) was performed on hip scans and trabecular bone score (TBS) on the LS scans to assess bone quality. Site- and sex-specific centile curves and tables were generated using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Clinicians and researchers can use these Canadian reference data as a tool to assess body composition, TBS and AHA parameters across the adult lifespan.

Predicting fragility fractures based on frailty and bone mineral density among rural community-dwelling older adults

OBJECTIVE

We aim to investigate the association between bone mineral density (BMD) measurement and fragility fractures and assess the predictive value of combining BMD measurement and frailty for fracture risk assessment.

METHODS

This retrospective cohort study analyzed data from 5126 rural Koreans in the Chungju Metabolic Disease Cohort study. Frailty was defined using Fried's frailty phenotype. Fractures were assessed via structured medical interviews. Adjusted odds ratios (ORs) were calculated considering age, sex, body mass index, behavior, BMD, handgrip strength, medications, and comorbidities.

RESULTS

The study cohort consisted of 5126 participants comprising 1955 (38.1%) males and 3171 (61.9%) females. Osteoporosis significantly increased the fracture risk across all types, except vertebral fracture, with adjusted OR (95% CI) of 1.89 (1.23-3.47) for any fracture, 2.05 (1.37-2.98) for hip fracture, 2.18 (1.06-4.50) for other fracture, and 1.71 (1.03-3.63) for major osteoporotic fracture (MOF). Frail individuals exhibited significantly increased risk for any fracture (OR 2.12; 95% CI, 1.21-3.71), vertebral fracture (2.48; 1.84-3.61), hip fracture (2.52; 1.09-3.21), other fracture (2.82; 1.19-8.53), and MOF (1.87; 1.01-3.47). The combination of frailty and BMD further increased the risks, with frail individuals demonstrating elevated ORs across BMD categories. In subgroup analyses, men showed a significant association between frailty with osteoporosis in hip fracture and MOF. Frail women with osteoporosis exhibited the highest risks for all fractures, particularly vertebral (OR 5.12; 95% CI, 2.07-9.68) and MOF (OR 5.19; 95% CI, 2.07-6.61). Age-specific analysis revealed that individuals aged 70 and older exhibited markedly higher fracture risks compared with those under 70. The combination of frailty and low BMD further elevated the fracture risk. Frailty was applied with BMD and demonstrated superior risk prediction for MOF compared with that with either score alone (area under the curve 0.825; P = .000).

CONCLUSIONS

Combining frailty with BMD provides a more accurate fracture risk assessment for individuals over 50 years.

Development of Hip Bone Geometry During Gender-Affirming Hormone Therapy in Transgender Adolescents Resembles That of the Experienced Gender When Pubertal Suspension Is Started in Early Puberty

Bone geometry can be described in terms of periosteal and endocortical growth and is partly determined by sex steroids. Periosteal and endocortical apposition are thought to be regulated by testosterone and estrogen, respectively. Gender-affirming hormone (GAH) treatment with sex steroids in transgender people might affect bone geometry. However, in adult transgender people, no change in bone geometry during GAH was observed. In this study, we investigated changes in bone geometry among transgender adolescents using a gonadotropin-releasing hormone agonist (GnRHa) and GAH before achieving peak bone mass. Transgender adolescents treated with GnRHa and subsequent GAH before the age of 18 years were eligible for inclusion. Participants were grouped based on their Tanner stage at the start of GnRHa treatment and divided into early, mid, and late puberty groups. Hip structure analysis software calculating subperiosteal width (SPW) and endocortical diameter (ED) was applied to dual-energy X-ray absorptiometry scans performed at the start of GnRHa and GAH treatments, and after ≥2 years of GAH treatment. Mixed-model analyses were performed to study differences over time. Data were visually compared with reference values of the general population. A total of 322 participants were included, of whom 106 were trans women and 216 trans men. In both trans women and trans men, participants resembled the reference curve for SPW and ED of the experienced gender but only when GnRHa was started during early puberty. Those who started during mid and late puberty remained within the reference curve of the gender assigned at birth. A possible explanation might be sought in the phenomenon of programming, which conceptualizes that stimuli during critical windows of development can have major consequences throughout one's life span. Therefore, this study adds insights into sex-specific bone geometry development during puberty of transgender adolescents treated with GnRHa, as well as the general population. © 2021 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Impact of sleeve gastrectomy on hip structural analysis in adolescents and young adults with obesity

BACKGROUND

Sleeve gastrectomy (SG), the most commonly performed metabolic and bariatric surgery, is associated with reductions in areal bone mineral density at multiple sites, and changes in bone structure at the distal radius and tibia without reductions in strength estimates at these peripheral sites. Data are lacking regarding effects on hip strength estimates.

OBJECTIVE

To evaluate effects of SG on measures of hip structural analysis in adolescents and young adults over 12 months using dual-energy x-ray absorptiometry.

SETTINGS

Translational and Clinical Research Center.

METHODS

We enrolled 48 youth 14- to 22-years old with moderate-to-severe obesity; 24 underwent SG and 24 controls were followed without surgery (18 females, 6 males in each group). Hip structure was assessed using dual-energy x-ray absorptiometry at baseline and 12 months. Analyses are adjusted for age, sex, race, and the baseline bone measure.

RESULTS

The SG group lost 25.9% weight versus .3% in controls. Compared with controls, SG had reductions in narrow neck, intertrochanteric and femoral shaft bone mineral density Z-scores (P ≤ .012). Furthermore, SG had greater reductions in narrow neck and intertrochanteric region (but not femoral shaft) cross-sectional area, cortical thickness, cross-sectional moment of inertia and section modulus, and increases in buckling ratio (P ≤ .039). Differences were attenuated after adjusting for 12-month body mass index change. At 12 months, differences were minimal after adjusting for age, sex, race, and weight.

CONCLUSIONS

Over 12 months, SG had negative effects at the narrow neck and intertrochanteric regions of the hip, but not the femoral shaft. Reduced body mass index may compensate for these deleterious effects on bone.

Bone Traits Seem to Develop Also During the Third Decade in Life-Normative Cross-Sectional Data on 1083 Men Aged 18-28 Years

By identifying individuals with low peak bone mass (PBM) at young age, early targeted interventions to reduce future fracture risk could be possible. Peripheral quantitative computed tomography (pQCT) is in many ways superior to the gold standard dual-energy X-ray absorptiometry (DXA), as cortical and trabecular compartments as well as the volumetric density and bone structure can be examined separately. Because each of these traits contributes independently to bone strength, it is probable that pQCT provides an even better fracture risk estimation than DXA. Currently, the clinical applications of pQCT are limited partly because comprehensive normative pQCT data, especially in young men, are not readily available. We therefore set up a study in young men with the following objectives: (1) to identify peak ages in pQCT bone traits with special reference to PBM and peak bone strength; and (2) to provide normative pQCT data. We measured volumetric bone mineral density and structural parameters at ultradistal (trabecular bone) and diaphyseal radius and tibia (cortical bone) by pQCT scans (Stratec XCT2000®; Stratec Medizintechnik GmbH, Pforzheim, Germany) in a population-based age-stratified sample of 1083 men aged 18-28 yr residing in greater Malmö, Sweden. Group differences in 1-yr classes were evaluated by analysis of variance. We found similar bone traits in age groups at ultradistal sites whereas most bone traits at diaphyseal sites were higher with higher ages, however with different increment patterns depending on the specific trait. In Swedish young adult men, we found that different bone traits continued to change after age 18, but at different rates, indicating that peak areal bone mineral density (as measured by DXA) and peak bone strength may be reached at different ages.

An Increase in Forearm Cortical Bone Size After Menopause May Influence the Estimated Bone Mineral Loss--A 28-Year Prospective Observational Study

Areal bone mineral density (aBMD) is the most common estimate of bone mass, incorporated in the World Health Organization definition of osteoporosis. However, aBMD depends on not only the amount of mineral but also the bone size. The estimated postmenopausal decline in aBMD could because of this be influenced by changes in bone size.We measured bone mineral content (BMC; mg), aBMD (mg/cm2), and bone width (mm) by single-photon absorptiometry at the cortical site of the forearm in a population-based sample of 105 Caucasian women. We conducted 12 measurements during a 28-yr period from mean 5 yr (range: 2-9) before menopause to mean 24 yr (range: 18-28) after menopause. We calculated individual slopes for changes in the periods before menopause, 0-<8, 8-<16, and 16-28 yr after menopause. Data are presented as means with 95% confidence intervals. The annual BMC changes in the 4 periods were -1.4% (-0.1, -2.6), -1.1% (-0.9, -1.4), -1.2% (-0.9, -1.6), and -1.1% (-0.8, -1.4) and the annual increase in bone width 0.4% (-1.2, 1.9), 0.7% (0.5, 0.9), 0.1% (-0.2, 0.4), and 0.1% (-0.2, 0.4). BMC loss was similar in all periods, whereas the increase in bone width was higher in the first postmenopausal period than in the second (p=0.003) and the third (p=0.01) postmenopausal periods. Menopause is followed by a transient increase in forearm bone size that will influence the by aBMD estimated cortical loss in bone minerals.

Influence of bone mineral density and hip geometry on the different types of hip fracture

The aim of this study was to assess the influence of bone mineral density and hip geometry on the fragility fracture of femoral neck and trochanteric region. There were 95 menopausal females of age ≥ 50 years with fragility fracture of hip, including 55 cases of femoral neck fracture and 40 cases of trochanteric fracture. Another 63 non-fractured females with normal bone mineral density (BMD) were chosen as control. BMD, hip axis length, neck-shaft angle and structural parameters including cross surface area, cortical thickness and buckling ratio were detected and compared. Compared with control group, the patients with femoral neck fracture or trochanteric fractures had significantly lower BMD of femoral neck, as well as lower cross surface area and cortical thickness and higher buckling ratio in femoral neck and trochanteric region. There were no significant differences of BMD and structural parameters in the femoral neck fracture group and intertrochanteric fracture group. Hip axis length and neck-shaft angle were not significantly different among three groups. The significant changes of BMD and proximal femur geometry were present in the fragility fracture of femoral neck and trochanteric region. The different types of hip fractures cannot be explained by these changes.

Osteoarthritis of the Distal Interphalangeal and First Carpometacarpal Joints is Associated with High Bone Mass in Women and Small Bone Size and Low Lean Mass in Men

Objective:

To determine if primary hand osteoarthritis (OA) is associated with abnormal bone and anthropometric traits.

Methods:

We used DXA to measure total body bone mineral density (BMD), femoral neck width (bone size) and total body lean and fat mass in 39 subjects with hand OA (primary DIP and/or CMC I) and 164 controls. Data are presented as mean Z-scores or Odds Ratios (OR) with 95% confidence intervals.

Results:

Women with hand OA had (compared to controls) higher BMD (0.5(0.1,0.9)) but similar bone size (-0.3(-0.8,0.2)), lean mass (0.3(-0.3,0.9)), fat mass (-0.1(-0.6,0.5)) and BMI (0.0(-0.6,0.6)). Men with hand OA had (compared to controls) similar BMD (-0.1(-0.7,0.6)), smaller bone size (-0.5(-1.1,-0.01)), lower lean mass (-0.6(-1.1,-0.04)), and similar fat mass (-0.2(-0.7,0.4)) and BMI -0.1(-0.6,0.6). In women, each SD higher BMD was associated with an OR of 1.8 (1.03, 3.3) for having hand OA. In men each SD smaller bone size was associated with an OR of 1.8 (1.02, 3.1) and each SD lower proportion of lean body mass with an OR of 1.9 (1.1, 3.3) for having hand OA.

Conclusion:

Women with primary DIP finger joint and/or CMC I joint OA have a phenotype with higher BMD while men with the disease have a smaller bone size and lower lean body mass.

Growth and aging of proximal femoral bone: a study with women spanning three generations

Osteoporotic hip fracture is a serious clinical event associated with high morbidity and mortality. Understanding femoral growth patterns is important for promoting bone health in the young and preventing fractures in later life. In this study, growth patterns of areal bone mineral density (aBMD) and geometric properties of the proximal femur were measured by dual-energy X-ray absorptiometry. They were studied in 251 girls from premenarche (11.2 ± 0.7 years) to late adolescence (18.3 ± 1.1 years) and compared with their premenopausal mothers (n = 128, aged 44.9 ± 4.1 years) and postmenopausal grandmothers (n = 128, aged 70.0 ± 6.3 years). Hip axis length (HAL) was the first to reach peak growth velocity (-10.5 months before menarche), followed by neck diameter (ND) and neck cross-sectional area (CSA), (-7.1 and -4.1 months before menarche, respectively). Both neck-shaft angle (NSA) and aBMD of neck and total hip peaked at menarche. At 18 years (7-year follow-up), girls already had higher femoral neck aBMD but similar HAL and NSA compared with their mothers. Grandmothers had the longest HAL, narrowest NSA, widest ND but lowest aBMD and CSA. Hip strength index (HSI), an index of femoral neck strength during a fall, dropped rapidly after menarche in girls but thereafter remained relatively constant. Grandmothers had lower HSI than either mothers or girls. In conclusion, differences in proximal femoral bone mass and structure in adulthood are largely established before menarche, indicating that heritable factors are responsible for most of the individual variance. The development of geometric properties precedes aBMD in puberty, resulting in relatively constant hip strength after menarche. This asynchronous growth leads to adaptation of bone strength to the imposed loads, avoiding fractures in a biologically efficient manner. Both deterioration of aBMD and inadequate compensatory change in bone geometry after menopause contribute to the increased fracture risk later in life.

Patients with knee osteoarthritis have a phenotype with higher bone mass, higher fat mass, and lower lean body mass

BACKGROUND

Although knee osteoarthritis (OA) is common, its etiology is poorly understood. Specifically, it is not known whether knee OA is associated with abnormal anthropometric and musculoskeletal characteristics known to be associated with OA in general. We recently studied this topic for patients with hip arthritis; however, it is important to evaluate it for knee OA separately, because there are reports indicating that patients with primary OA in different joints may have a different phenotype.

QUESTIONS/PURPOSES

Do patients with primary knee OA have a phenotype with higher bone mineral density (BMD), higher body mass index (BMI), larger skeletal size, lower lean body mass, and higher fat content?

METHODS

We included 38 women and 74 men (mean age, 61 years; range, 34-85 years) with primary knee OA and 122 women and 121 men as control subjects. We used dual-energy x-ray absorptiometry to measure total body BMD (g/cm2), femoral neck width (cm), fat and lean mass (%), and BMI (kg/m2). Z scores were calculated for each individual. Data are presented as means with 95% confidence intervals.

RESULTS

Women with knee OA had the following Z scores: total body BMD 0.8 (0.5-1.0); BMI 1.6 (1.1-2.0); femoral neck width 0.1 (-0.3 to 0.4); proportion of lean mass -1.0 (-1.5 to -0.6); and proportion of fat mass 1.0 (0.6-1.4). Men with knee OA had the following Z scores: total body BMD 0.5 (0.3-0.7); BMI 0.9 (0.6-1.1); femoral neck width 0.3 (0.1-0.7); proportion of lean mass -0.9 (-1.1 to -0.8); and proportion of fat mass 0.7 (0.5-0.9).

CONCLUSIONS

Women and men with idiopathic knee OA have a phenotype with higher BMD, higher BMI, proportionally higher fat mass, and proportionally lower lean body mass. Men also have a larger skeletal size.

CLINICAL RELEVANCE

A higher BMD may lead to stiffer bone, a higher BMI to a greater joint load, and a proportionally lower lean body (muscle) mass to lower joint-protective ability, and all trait deviations probably predispose for knee OA.

Liquid chromatography-selected reaction monitoring (LC-SRM) approach for the separation and quantitation of sialylated N-glycans linkage isomers

The study of N-linked glycans is among the most challenging bioanalytical tasks because of their complexity and variety. The presence of glycoform families that differ only in branching and/or linkage position makes the identification and quantitation of individual glycans exceedingly difficult. Quantitation of these individual glycans is important because changes in the abundance of these isomers are often associated with significant biomedical events. For instance, previous studies have shown that the ratio of α2-3 to α2-6 linked sialic acid (SA) plays an important role in cancer biology. Consequently, quantitative methods to detect alterations in the ratios of glycans based on their SA linkages could serve as a diagnostic tool in oncology, yet traditional glycomic profiling cannot readily differentiate between these linkage isomers. Here, we present a liquid chromatography-selected reaction monitoring (LC-SRM) approach that we demonstrate is capable of quantitating the individual SA linkage isomers. The LC method is capable of separating sialylated N-glycan isomers differing in α2-3 and α2-6 linkages using a novel superficially porous particle (Fused-Core) Penta-HILIC (hydrophilic interaction liquid chromatography) column. SRM detection provides the relative quantitation of each SA linkage isomer, and minimizes interferences from coeluting glycans that are problematic for UV/Fluorescence based quantitation. With our approach, the relative quantitation of each SA linkage isomer is obtained from a straightforward liquid chromatography-mass spectrometry (LC-MS) experiment.

Hip structural parameters over 96 weeks in HIV-infected adults switching treatment to tenofovir-emtricitabine or abacavir-lamivudine

Background

Therapy with tenofovir is associated with lower bone mineral density (BMD), higher markers of bone turnover and increased fracture risk in HIV-infected adults. Bone structural parameters generated by hip structural analysis may represent a separate measure of bone strength, but have not been assessed in HIV.

Methods

Dual-energy X-ray absorptiometry (DXA) scans from 254 HIV-infected adults randomised to simplify their existing dual nucleoside analogue reverse transcriptase inhibitor therapy to coformulated tenofovir-emtricitabine or abacavir-lamivudine were analysed using DXA-derived hip structural analysis software. Hip structural parameters included femoral strength index, section modulus, cross-sectional area, and cross-sectional moment of inertia. We used one-way ANOVA to test the relationship between nucleoside analogue type at baseline and structural parameters, multivariable analysis to assess baseline covariates associated with femoral strength index, and t-tests to compare mean change in structural parameters over 96 weeks between randomised groups.

Results

Participants taking tenofovir at baseline had lower section modulus (−107.3 mm², p = 0.001), lower cross-sectional area (−15.01 mm³, p = 0.001), and lower cross-sectional moment of inertia (−2,036.8 mm⁴, p = 0.007) than those receiving other nucleoside analogues. After adjustment for baseline risk factors, the association remained significant for section modulus (p = 0.008) and cross-sectional area (p = 0.002). Baseline covariates significantly associated with higher femoral strength index were higher spine T-score (p = 0.001), lower body fat mass (p<0.001), lower bone alkaline phosphatase (p = 0.025), and higher osteoprotegerin (p = 0.024). Hip structural parameters did not change significantly over 96 weeks and none was significantly affected by treatment simplification to tenofovir-emtricitabine or abacavir-lamivudine.

Conclusion

In this population, tenofovir use was associated with reduced composite indices of bone strength as measured by hip structural analysis, but none of the structural parameters improved significantly over 96 weeks with tenofovir cessation.

Trial Registration

ClinicalTrials.gov NCT00192634

Patients with hip osteoarthritis have a phenotype with high bone mass and low lean body mass

BACKGROUND

Although hip osteoarthritis (OA) is common, its etiology is poorly understood. Specifically, it is not known whether hip OA is associated with abnormal relationships among the anthropometric and musculoskeletal characteristics that are associated with OA in general.

QUESTIONS

We asked whether patients with primary hip OA have a phenotype with higher bone mineral density (BMD), higher BMI, larger skeletal size, lower lean body mass, and higher fat content.

MATERIAL AND METHODS

We included 30 women and 32 men (mean age, 66 years; range, 42-84 years) with primary hip OA and 96 women and 91 men as control subjects. Dual energy x-ray absorptiometry was used to measure total body BMD (g/cm(2)), femoral neck width (cm), fat and lean mass (%), and BMI (kg/m(2)). Z scores were calculated for each individual. Data are presented as means with 95% CI.

RESULTS

Women with hip OA had the following Z scores: total body BMD 0.6 (0.3, 1.0); BMI 0.6 (0.2, 1.0); femoral neck width 0.2 (-0.6, 1.0); percent total body lean mass -0.9 (-1.2, -0.5); and percent total body fat mass 0.6 (0.2, 0.9). Men with hip OA had the following mean Z scores: total body BMD 0.5 (0.0, 1.0); BMI 0.8 (0.3, 1.3); femoral neck width 0.4 (0.01, 0.9); percent total body lean mass -0.8 (-1.1, -0.5); and percent total body fat mass 0.5 (0.2, 0.8).

CONCLUSIONS

Women and men with idiopathic hip OA have a phenotype with higher BMD, higher BMI, proportionally higher fat mass, and proportionally lower lean body mass. Men also have a larger skeletal size.

CLINICAL RELEVANCE

A higher BMD may lead to a stiffer bone and a proportionally lower lean body mass to lower joint-protective ability, both traits probably predisposing for hip OA.

Hip structural analysis in adolescent boys with anorexia nervosa and controls

CONTEXT

We have reported lower hip bone mineral density (BMD) in adolescent boys with anorexia nervosa (AN) compared with controls. Although studies have described bone structure in girls with AN, these data are not available for boys. Hip structural analysis (HSA) using dual-energy x-ray absorptiometry is a validated technique to assess hip geometry and strength while avoiding radiation associated with quantitative computed tomography.

OBJECTIVE

We hypothesized that boys with AN would have impaired hip structure/strength (assessed by HSA) compared with controls.

DESIGN AND SETTING

We conducted a cross-sectional study at a clinical research center.

SUBJECTS AND INTERVENTION

We used HSA techniques on hip dual-energy x-ray absorptiometry scans in 31 previously enrolled boys, 15 with AN and 16 normal-weight controls, 12 to 19 years old.

RESULTS

AN boys had lower body mass index SD score (P < .0001), testosterone (P = .0005), and estradiol (P = .006) than controls. A larger proportion of AN boys had BMD Z-scores <-1 at the femoral neck (60% vs 12.5%, P = 0008). Using HSA, at the narrow neck and trochanter region, boys with AN had lower cross-sectional area (P = .03, 0.02) and cortical thickness (P = .02, 0.03). Buckling ratio at the trochanter region was higher in AN (P = .008). After controlling for age and height, subperiosteal width at the femoral shaft, cross-sectional moment of inertia (narrow neck and femoral shaft), and section modulus (all sites) were lower in AN. The strongest associations of HSA measures were observed with lean mass, testosterone, and estradiol. On multivariate analysis, lean mass remained associated with most HSA measures.

CONCLUSIONS

Boys with AN have impaired hip geometric parameters, associated with lower lean mass.

Hip structural analysis in adolescent and young adult oligoamenorrheic and eumenorrheic athletes and nonathletes

CONTEXT

Stress fractures are common in endurance athletes. Whereas studies have described distal tibia bone structure in athletes, there are few data regarding hip geometric parameters. Hip structural analysis (HSA) using dual-energy x-ray absorptiometry is a validated technique to assess hip bone structure.

OBJECTIVES

The purpose of this study was to compare hip geometry in young oligoamenorrheic athletes (AAs), eumenorrheic athletes (EAs), and nonathletes using HSA. We hypothesized that AAs would have impaired bone structure compared with that of EAs.

DESIGN

This was a cross-sectional study.

SETTING

The setting was a clinical research center.

SUBJECTS

We enrolled 55 AAs, 24 EAs, and 23 nonathletes of normal weight who were 14 to 22 years old. Athletes ran ≥20 miles/wk or were engaged in weight-bearing sports for ≥4 hours/wk.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry was used for HSA and hip areal bone mineral density (aBMD).

RESULTS

Hip aBMD Z-scores were lower in AAs and in nonathletes than in EAs (P = .002). A larger proportion of AAs than EAs and nonathletes had hip Z-scores <-1 (30.9, 4.2, 17.4%, P = .01). At the narrow neck, trochanteric region, and femoral shaft, subperiosteal width, cross-sectional moment of inertia, and section modulus were higher in EAs than in nonathletes; values in AAs did not differ from those of nonathletes. Cross-sectional area was lower in AAs and in nonathletes than in EAs. Groups did not differ for cortical thickness or buckling ratio. Group differences were lost after adjustment for lean mass but not aBMD.

CONCLUSIONS

In an eugonadal state, athletic activity confers benefits for hip structure independent of aBMD. This advantage is lost in AAs, who do not differ from nonathletes for most parameters and fare worse than EAs for cross-sectional area.

Femoral geometric parameters and BMD measurements by DXA in adult patients with different types of osteogenesis imperfecta

OBJECTIVES

Osteogenesis imperfecta (OI) is an inherited disorder characterized by increased bone fragility with recurrent fractures that leads to skeletal deformities in severe cases. Consequently, in most OI patients, the hip is the only reliable measuring site for estimating future fracture risk. The aim of the study was to assess the applicability of hip structure analysis (HSA) by DXA in adult patients with osteogenesis imperfecta.

MATERIALS AND METHODS

We evaluated bone mineral density (BMD) and hip structure analysis (HSA) by DXA, including cross-sectional area (CSA), cross-sectional moment of inertia (CSMI) and femoral strength index (FSI) in 30 adult patients with different types of OI and 30 age-matched healthy controls (CO). The OI total group (OI-tot) was divided into two subgroups: the mild OI I group (OI-I) and the more severe OI III and IV group (OI-III-IV).

RESULTS

The mean neck BMD of OI-I and OI-III-IV were significantly lower compared to CO (-15.9 %, p < 0.005 and -37.5 %, p < 0.001 respectively). Similar results were observed at trochanter and total hip. CSA and the CSMI value were significantly lower for OI-I (-23.2 %, p < 0.001) and OI-III-IV (-45.9 %, p < 0.001) in comparison to CO. In addition, significant differences were found between the mild OI-I and the severe OI-III-IV group (-29.6 %, p < 0.05). FSI was significantly decreased in the OI-III-IV (25.7 %, p < 0.05) in comparison to the CO. Furthermore, significant correlations between BMD and HSA and between HSA and height and weight were found in osteogenesis imperfecta and controls.

CONCLUSION

BMD measurement in osteogenesis imperfecta patients is very critical. The combination of BMD and geometric structural measurements at the hip in osteogenesis imperfecta patients may represent an additional helpful means in estimating bone strength and fracture risk.

Age-related differences in Achilles tendon properties and triceps surae muscle architecture in vivo

This study examined the concurrent age-related differences in muscle and tendon structure and properties. Achilles tendon morphology and mechanical properties and triceps surae muscle architecture were measured from 100 subjects [33 young (24 ± 2 yr) and 67 old (75 ± 3 yr)]. Motion analysis-assisted ultrasonography was used to determine tendon stiffness, Young's modulus, and hysteresis during isometric ramp contractions. Ultrasonography was used to measure muscle architectural features and size and tendon cross-sectional area. Older participants had 17% lower (P < 0.01) Achilles tendon stiffness and 32% lower (P < 0.001) Young's modulus than young participants. Tendon cross-sectional area was also 16% larger (P < 0.001) in older participants. Triceps surae muscle size was smaller (P < 0.05) and gastrocnemius medialis muscle fascicle length shorter (P < 0.05) in old compared with young. Maximal plantarflexion force was associated with tendon stiffness and Young's modulus (r = 0.580, P < 0.001 and r = 0.561, P < 0.001, respectively). Comparison between old and young subjects with similar strengths did not reveal a difference in tendon stiffness. The results suggest that regardless of age, Achilles tendon mechanical properties adapt to match the level of muscle performance. Old people may compensate for lower tendon material properties by increasing tendon cross-sectional area. Lower tendon stiffness in older subjects might be beneficial for movement economy in low-intensity locomotion and thus optimized for their daily activities.