Differences in geometric strength at the contralateral hip between men with hip fracture and non-fractured comparators.

Older men sustain excess bone mineral density (BMD) declines after hip fracture; however, BMD provides no information on mechanical structure and strength. The aim was to assess whether changes in hip bone geometry in older men after hip fracture differ than that expected with aging. Two cohorts were used: Baltimore Hip Studies 7th cohort (BHS-7) and Baltimore Men's Osteoporosis Study (MOST).

Longitudinal changes in hip geometry in relation to the final menstrual period: Study of Women's Health Across the Nation (SWAN).

Background: In SWAN, we showed that accelerated loss of bone mineral density (BMD) begins 1 year before the final menstrual period (FMP) to 2 years after the FMP and slows thereafter. However, the risk of fracture depends on both BMD and bone geometry. The hip structural analysis (HSA) measures important geometric properties of bone.

Femoral stress is prominently associated with fracture risk in children: The Generation R Study.

Bone modeling is an important process in the growing skeleton. An inadequate bone modeling in response to mechanical loads would lead some children to develop weaker bones than others. The resulting higher stresses in the bones would render them more susceptible to fracture.

Identification of Novel Loci Associated With Hip Shape: A Meta-Analysis of Genomewide Association Studies.

We aimed to report the first genomewide association study (GWAS) meta-analysis of dual-energy X-ray absorptiometry (DXA)-derived hip shape, which is thought to be related to the risk of both hip osteoarthritis and hip fracture. Ten hip shape modes (HSMs) were derived by statistical shape modeling using SHAPE software, from hip DXA scans in the Avon Longitudinal Study of Parents and Children (ALSPAC; adult females), TwinsUK (mixed sex), Framingham Osteoporosis Study (FOS; mixed), Osteoporotic Fractures in Men study (MrOS), and Study of Osteoporotic Fractures (SOF; females) (total N = 15,934). Associations were adjusted for age, sex, and ancestry.

Trabecular Bone Score and Hip Structural Analysis in Patients With Atypical Femur Fractures.

Bisphosphonate use has declined dramatically in recent years, partly because of fear of rare side effects like atypical femur fractures (AFFs). It is therefore desirable to have a diagnostic method to identify those at risk of AFF to prevent this serious complication. We compared trabecular microarchitecture and hip geometry between 30 patients with AFF and 141 controls of similar age and sex, using bisphosphonates.

Difference in the trajectory of change in bone geometry as measured by hip structural analysis in the narrow neck, intertrochanteric region, and femoral shaft between men and women following hip fracture.

Prior studies have shown that women have declines in bone structure and strength after hip fracture, but it is unclear whether men sustain similar changes. Therefore, the objective was to examine sex differences in proximal femur geometry following hip fracture. Hip structural analysis was used to derive metrics of bone structure and strength: aerial bone mineral density, cross-sectional bone area (CSA), cortical outer diameter, section modulus (SM), and buckling ratio (BR) from dual-energy x-ray absorptiometry scans performed at baseline (within 22days of hospital admission), two, six, or twelve months after hip fracture in men and women (n=282) enrolled in the Baltimore Hip Studies 7th cohort.

Bone Mass and Strength in School-Age Children Exhibit Sexual Dimorphism Related to Differences in Lean Mass: The Generation R Study.

Bone strength, a key determinant of fracture risk, has been shown to display clear sexual dimorphism after puberty. We sought to determine whether sex differences in bone mass and hip bone geometry as an index of strength exist in school-age prepubertal children and the degree to which the differences are independent of body size and lean mass. We studied 3514 children whose whole-body and hip scans were measured using the same densitometer (GE-Lunar iDXA) at a mean age of 6.

Measurement of Hip Geometry-Technical Background.

Conventional dual-energy X-ray absorptiometry images display a digital projection of the inorganic mineral mass in a scanned region. Bone mineral density software generates an average of the pixels within one or more regions. Although not used in the conventional analysis, the images also contain dimensional information limited to the plane of the image.

The effects of bazedoxifene on bone structural strength evaluated by hip structure analysis.

Bazedoxifene (BZA) is a selective estrogen receptor modulator that has been shown to prevent and treat postmenopausal osteoporosis. Hip structure analysis (HSA) can be used to extract bone structural properties related to strength from hip bone mineral density (BMD) scans. This exploratory analysis used HSA to evaluate changes in hip structural geometry in postmenopausal women enrolled in a phase 3 osteoporosis treatment study who were treated with BZA 20mg or placebo for 2 years.

Ratchet effect study in Si/SiGe heterostructures in the presence of asymmetrical antidots for different polarizations of microwaves.

In this work, we studied the photovoltage response of an antidot lattice to microwave radiation for different antidot parameters. The study was carried out in a Si/SiGe heterostructure by illuminating the antidot lattice with linearly polarized microwaves and recording the polarity of induced photovoltage for different angles of incidence. Our study revealed that with increased antidot density and etching depth, the polarity of induced photovoltage changed when the angle of incidence was rotated 90 degrees.

Adolescent physical activity and bone strength at the proximal femur in adulthood.

Introduction: Physical activity (PA) enhances bone structural strength at the proximal femur in adolescence, but whether these benefits are maintained into early adulthood remains unknown. The purpose of this study was to investigate whether males and females, described as active, average, and inactive during adolescence, display differences in structural strength at the proximal femur in early adulthood (20-30 yr).

Methods: One hundred four participants (55 males and 49 females) from the Pediatric Bone Mineral Accrual Study (PBMAS) were categorized into adolescent PA groupings (inactive, average, and active) using the Physical Activity Questionnaire for Adolescents.

Effect of vitamin D replacement on hip structural geometry in adolescents: a randomized controlled trial.

Background: We have shown in a randomized controlled trial that vitamin D increases bone mass, lean mass and bone area in adolescent girls, but not boys. These increments may translate into improvements in bone geometry and therefore bone strength. This study investigated the impact of vitamin D on hip geometric dimensions from DXA-derived hip structural analyses in adolescents who participated in the trial.

Evidence for impaired skeletal load adaptation among Canadian women with type 2 diabetes mellitus: insight into the BMD and bone fragility paradox.

Objective: Recent data suggest that women with type 2 diabetes mellitus (T2DM) might be more susceptible to fractures due to an impaired adaptive response to mechanical load, despite reportedly higher bone mineral density (BMD). The purpose of this study was to use an engineering beam analysis to calculate and compare the load stresses on the femurs of healthy women and women with T2DM and compare these levels to conventional measures of femoral neck BMD.

Materials/methods: We studied 3658 women who participated in the Canadian Multicentre Osteoporosis Study (CaMos), and who had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans.

Does hormone replacement normalize bone geometry in adolescents with anorexia nervosa?

Young women with anorexia nervosa (AN) have reduced secretion of dehydroepiandrosterone (DHEA) and estrogen contributing to skeletal deficits. In this randomized, placebo-controlled trial, we investigated the effects of oral DHEA + combined oral contraceptive (COC) versus placebo on changes in bone geometry in young women with AN. Eighty women with AN, aged 13 to 27 years, received a random, double-blinded assignment to micronized DHEA (50 mg/day) + COC (20 µg ethinyl estradiol/0.

Successive binary algebraic reconstruction technique: an algorithm for reconstruction from limited angle and limited number of projections decomposed into individual components.

Relatively high radiation CT techniques are being widely used in diagnostic imaging raising the concerns about cancer risk especially for routine screening of asymptomatic populations. An important strategy for dose reduction is to reduce the number of projections, although doing so with high image quality is technically difficult. We developed an algorithm to reconstruct discrete (limited gray scale) images decomposed into individual tissue types from a small number of projections acquired over a limited view angle.

Heterogeneity in skeletal load adaptation points to a role for modeling in the pathogenesis of osteoporotic fracture.

Genetic, environmental, or hormonal factors may cause heterogeneity in skeletal load response. Individuals with reduced sensitivity to load should require higher strains to generate an adaptive response, consequently have weaker bones and fracture more frequently. The purpose of our study was to determine if stresses (proportional to strains) at the femoral neck under equivalent loads were higher in women with a history of fractures compared with women without fractures.

Effect of exercise training combined with isoflavone supplementation on bone and lipids in postmenopausal women: a randomized clinical trial.

We determined the effects of 2 years of exercise training and soy isoflavone supplementation on bone mass and lipids in postmenopausal women provided with calcium and vitamin D. Women were randomized to four groups: exercise training (Ex); isoflavone supplementation (Iso: 165 mg/d [105 mg/d aglycone equivalent]); combined Ex and Iso (ExIso); and placebo (control). Exercise included resistance training (2 days/week) and walking (4 days/week).

Hip strength in adults with type 1 diabetes is associated with age at onset of diabetes.

We investigated the association of age at onset of type 1 diabetes with areal bone mineral density (aBMD), estimates of bone strength, and outer diameter. Using dual-energy X-ray absorptiometry (DXA), aBMD, axial strength (cross-sectional area [CSA]), bending strength (section modulus [SM]), and outer diameter at the narrow neck, intertrochanter, and shaft of the proximal femur were determined for 60 adults. Analysis of covariance (ANCOVA) was used to determine if the DXA-based measures of bone were related to age at onset and if this relationship differed by gender.

Rheumatoid arthritis is associated with less optimal hip structural geometry.

The overall goal of this study was to assess the longitudinal changes in bone strength in women reporting rheumatoid arthritis (RA; n=78) compared with nonarthritic control participants (n=4779) of the Women's Health Initiative bone mineral density (WHI-BMD) subcohort. Hip structural analysis program was applied to archived dual-energy X-ray absorptiometry scans (baseline, years 3, 6, and 9) to estimate bone mineral density (BMD) and hip structural geometry parameters in 3 femoral regions: narrow neck (NN), intertrochanteric (IT), and shaft (S). The association between RA and hip structural geometry was tested using linear regression and random coefficient models.

Talbot phase-contrast x-ray imaging for the small joints of the hand.

A high-resolution radiographic method for soft tissues in the small joints of the hand would aid in the study and treatment of rheumatoid arthritis (RA) and osteoarthritis (OA), which often attacks these joints. Of particular interest would be imaging with <100 µm resolution the joint cartilage, whose integrity is a main indicator of disease. Differential phase-contrast (DPC) or refraction-based x-ray imaging with Talbot grating interferometers could provide such a method, since it enhances soft tissue contrast and can be implemented with conventional x-ray tubes.

Stronger bone correlates with African admixture in African-American women.

Osteoporosis affects all populations, but the risk for low bone density and fracture varies greatly by self-reported race and ethnicity. In this article, the relationship between measured percent African admixture and hip structural geometry, estimated from the hip structural analysis (HSA) program, was examined in a subcohort of the Women's Health Initiative (WHI). The study sample included 793 African-American women and 8559 non-Hispanic white women.

Calcium plus vitamin D supplementation has limited effects on femoral geometric strength in older postmenopausal women: the Women's Health Initiative.

Calcium plus vitamin D (CaD) supplementation has a modest but significant effect on slowing loss of femoral bone mass and reducing risk of hip fractures in adherent postmenopausal women. The goal of this study was to determine if CaD supplementation influences hip structural parameters that are associated with fracture risk. We studied 1,970 postmenopausal women enrolled in the Women's Health Initiative randomized controlled trial of CaD at one of three bone mineral density (BMD) clinical centers.

Confounders in the association between exercise and femur bone in postmenopausal women.

Introduction: Abundant animal and human evidence demonstrates that loading stimuli generate positive adaptive changes in bone, but effects of activity on bone mineral density (BMD) are often modest and frequently equivocal.

Hypothesis: Physical activity effects on the femur would be better reflected in measurements of geometry than BMD.

Study Design: Cross-sectional cohort study.

Effects of raloxifene treatment on the structural geometry of the proximal femur in Japanese women with osteoporosis.

The purpose of this study was to clarify the effects of 2-year treatment with raloxifene on the proximal femoral geometry among Japanese patients with osteoporosis by hip structure analysis. One hundred ninety-eight community-dwelling postmenopausal women with osteoporosis were enrolled. The structural variables were areal bone mineral density (BMD), cross-sectional area (CSA), section modulus (index of resistance to bending forces), and buckling ratio (index of cortical instability).