Ethnic differences in femur geometry in the women's health initiative observational study

Association of osteoporotic fractures of femoral neck and femoral neck geometric parameters in native Chinese women

BACKGROUND

Although it is generally believed that the femoral neck fracture is related to the femoral neck geometric parameters (FNGPs), the association between the risk of osteoporotic fracture of the femoral neck and FNGPs in native Chinese women is still unclear.

METHODS

A total of 374 female patients (mean age 70.2 ± 9.32 years) with osteoporotic fracture of the femoral neck, and 374 non-fracture control groups were completely matched with the case group according to the age ratio of 1:1. Using DXA bone densitometer to measured eight FNGPs: the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compressive strength index (CSI) at the narrowest point of the femoral neck.

RESULTS

Compared with the control group, the average values of OD (2.9%), ED (4.5%), and BR (26.1%) in the patient group significantly increased (p = 0.015 to < 0.001), while CSA (‒15.3%), CT (‒18.2%), SM (‒10.3%), CSMI (‒6.4%), and CSI (‒10.8%) significantly decreased (all p < 0.001). The prevalence of osteoporosis in the lumbar spine, femoral neck, and total hip was, respectively, 82%, 81%, and 65% in fracture patients. Cox proportional hazard model analysis showed that in the age adjusted model, the fracture hazard ratio (HR) of CSA, CT, BR, SM, and CSI significantly increased (HRs = 1.60‒8.33; 95% CI = 1.08‒16.6; all p < 0.001). In the model adjusted for age and femoral neck BMD, HRs of CT (HRs = 3.90‒8.03; 95% CI = 2.45‒15.1; all p < 0.001) and BR (HRs = 1.62‒2.60; 95% CI = 1.20‒5.44; all p < 0.001) were still significantly increased.

CONCLUSION

These results suggest that the majority of osteoporotic fractures of the femoral neck of native Chinese women occur in patients with osteoporosis. CT thinning or BR increase of FNGPs may be independent predictors of fragility fracture of femoral neck in native Chinese women unrelated to BMD.

Femora of women with premature ovarian insufficiency exhibit reduced strength and misalignment with the transmitted vertical forces from the upper body

BACKGROUND

Women with premature ovarian insufficiency (POI) lack oestrogen, which is a key determinant of bone growth, epiphyseal closure, and bone tissue organisation. Although dual-energy X-ray absorptiometry (DXA)-derived areal bone mineral density (BMD) remains the gold standard for fracture risk evaluation, it does not fully characterise the skeletal abnormalities present in these women. Hence, we aimed to assess hip/femur anatomy, strength, and geometry and femoral alignment using advanced hip analysis (AHA).

METHODS

We conducted a cross-sectional, case-control study including 89 women with spontaneous normal karyotype POI (s-POI) or iatrogenic POI (i-POI), aged 20-50 years compared with 89 age- and body mass index (BMI)-matched population-based female controls. Hip anatomy, strength, geometrical parameters, and femur alignment were measured using hip DXA images and Lunar AHA software. Femoral orientation angle (FOA) was quantified as the overall orientation of the femur with respect to the axis of the forces transmitted from the upper body.

RESULTS

The median age of POI diagnosis was 35 (18-40) years; the mean POI duration at the time of DXA was 2.07 (range 0-13) years, and 84% of POI women received oestrogen therapy. Areal BMD at all sites was significantly lower in the POI group (all P < .05). Indices of compressive and bending strength were lower in women with POI compared with controls, specifically the cross-sectional area (CSA, mm2) and section modulus (SM, mm3) (139.30 ± 29.08 vs 157.29 ± 22.26, P < .001 and 665.21 ± 129.54 vs 575.53 ± 150.88, P < .001, respectively). The FOA was smaller (124.99 ± 3.18) in women with POI as compared with controls (128.04 ± 3.80; P < .001) at baseline and after adjusting for height and femoral neck BMD.

CONCLUSION

Alongside lower BMD at multiple sites, the femora of women with POI demonstrate reduced strength and a misalignment with forces transmitted from the upper body. Further research is needed to establish the role of these newly identified features and their role in fracture risk prediction in this population.

Association between muscle strength and mass and bone mineral density in the US general population: data from NHANES 1999-2002

PURPOSE

It is known that muscle strength and muscle mass play a crucial role in maintaining bone mineral density (BMD). Despite this, there are uncertainties about how muscle mass, lower extremity muscular strength, and BMD are related. We examined the impact of lower extremity muscle strength and mass on BMD in the general American population using cross-sectional analysis.

METHODS

In the study, we extracted 2165 individuals from the National Health and Nutrition Examination Survey 1999-2002. Multivariate logistic regression models were used to examine the association between muscle strength, muscle mass, and BMD. Fitted smoothing curves and generalized additive models were also performed. To ensure data stability and avoid confounding factors, subgroup analysis was also conducted on gender and race/ethnicity.

RESULTS

After full adjustment for potential confounders, significant positive associations were detected between peak force (PF) [0.167 (0.084, 0.249) P < 0.001], appendicular skeletal muscle index (ASMI) [0.029 (0.022, 0.036) P < 0.001], and lumbar spine BMD. A positive correlation was also found between PF, ASMI, and pelvis and total BMD. Following stratification by gender and race/ethnicity, our analyses illustrated a significant correlation between PF and lumbar spine BMD in both men [0.232 (0.130, 0.333) P < 0.001] and women [0.281 (0.142, 0.420) P < 0.001]. This was also seen in non-Hispanic white [0.178 (0.068, 0.288) P = 0.002], but not in non-Hispanic black, Mexican American and other race-ethnicity. Additionally, there was a positive link between ASMI and BMD in both genders in non-Hispanic whites, and non-Hispanic blacks, but not in any other racial group.

CONCLUSION

PF and ASMI were positively associated with BMD in American adults. In the future, the findings reported here may have profound implications for public health in terms of osteopenia and osteoporosis prevention, early diagnosis, and treatment.

Race/ethnic differences in the prevalence of osteoporosis, falls and fractures: a cross-sectional analysis of the Canadian Longitudinal Study on Aging

Most of the published epidemiology on osteoporosis is derived from White populations; still many countries have increasing ethno-culturally diverse populations, leading to gaps in the development of population-specific effective fracture prevention strategies. We describe differences in prevalent fracture and bone mineral density patterns in Canadians of different racial/ethnic backgrounds.

INTRODUCTION

We described prevalent fracture and bone mineral density (BMD) patterns in Canadians by their racial/ethnic backgrounds.

METHODS

For this cross-sectional analysis, we used the Canadian Longitudinal Study on Aging baseline data (2011-2015) of 22,091 randomly selected participants of Black, East Asian, South or Southeast Asian (SSEA) and White race/ethnic backgrounds, aged 45-85 years with available information on the presence or absence of self-reported prevalent low trauma fractures and femoral neck BMD (FNBMD) measurement. Logistic and linear regression models examined associations of race/ethnic background with fracture and FNBMD, respectively. Covariates included sex, age, height, body mass index (BMI), grip strength and physical performance score.

RESULTS

We identified 11,166 women and 10,925 men. Self-reported race/ethnic backgrounds were: 139 Black, 205 East Asian, 269 SSEA and 21,478 White. White participants were older (mean 62.5 years) than the other groups (60.5 years) and had a higher BMI (28.0 kg/m²) than both Asian groups, but lower than the Black group. The population-weighted prevalence of falls was 10.0%, and that of low trauma fracture was 12.0% ranging from 3.3% (Black) to 12.3% (White), with Black and SSEA Canadians having lower adjusted odds ratios (aOR) of low trauma fractures than White Canadians (Black, aOR = 0.3 [95% confidence interval: 0.1-0.7]; SSEA, aOR = 0.5 [0.3-0.8]). The mean (SD) FNBMD varied between groups: Black, 0.907 g/cm² (0.154); East Asian, 0.748 g/cm² (0.119); SSEA, 0.769 g/cm² (0.134); and White, 0.773 g/cm² (0.128). Adjusted linear regressions suggested that Black and both Asian groups had higher FNBMD compared to White.

CONCLUSION

Our results support the importance of characterizing bone health predictors in Canadians of different race/ethnic backgrounds to tailor the development of population-specific fracture prevention strategies.

The clinician's guide to prevention and treatment of osteoporosis

Osteoporosis is the most common metabolic bone disease in the USA and the world. It is a subclinical condition until complicated by fracture(s). These fractures place an enormous medical and personal burden on individuals who suffer from them and take a significant economic toll. Any new fracture in an adult aged 50 years or older signifies imminent elevated risk for subsequent fractures, particularly in the year following the initial fracture. What a patient perceives as an unfortunate accident may be seen as a sentinel event indicative of bone fragility and increased future fracture risk even when the result of considerable trauma. Clinical or subclinical vertebral fractures, the most common type of osteoporotic fractures, are associated with a 5-fold increased risk for additional vertebral fractures and a 2- to 3-fold increased risk for fractures at other sites. Untreated osteoporosis can lead to a vicious cycle of recurrent fracture(s), often resulting in disability and premature death. In appropriate patients, treatment with effective antifracture medication prevents fractures and improves outcomes. Primary care providers and medical specialists are critical gatekeepers who can identify fractures and initiate proven osteoporosis interventions. Osteoporosis detection, diagnosis, and treatment should be routine practice in all adult healthcare settings. The Bone Health and Osteoporosis Foundation (BHOF) - formerly the National Osteoporosis Foundation - first published the Clinician's Guide in 1999 to provide accurate information on osteoporosis prevention and treatment. Since that time, significant improvements have been made in diagnostic technologies and treatments for osteoporosis. Despite these advances, a disturbing gap persists in patient care. At-risk patients are often not screened to establish fracture probability and not educated about fracture prevention. Most concerning, the majority of highest risk women and men who have a fracture(s) are not diagnosed and do not receive effective, FDA-approved therapies. Even those prescribed appropriate therapy are unlikely to take the medication as prescribed. The Clinician's Guide offers concise recommendations regarding prevention, risk assessment, diagnosis, and treatment of osteoporosis in postmenopausal women and men aged 50 years and older. It includes indications for bone densitometry as well as fracture risk thresholds for pharmacologic intervention. Current medications build bone and/or decrease bone breakdown and dramatically reduce incident fractures. All antifracture therapeutics treat but do not cure the disease. Skeletal deterioration resumes sooner or later when a medication is discontinued-sooner for nonbisphosphonates and later for bisphosphonates. Even if normal BMD is achieved, osteoporosis and elevated risk for fracture are still present. The diagnosis of osteoporosis persists even if subsequent DXA T-scores are above - 2.5. Ongoing monitoring and strategic interventions will be necessary if fractures are to be avoided. In addition to pharmacotherapy, adequate intake of calcium and vitamin D, avoidance of smoking and excessive alcohol intake, weight-bearing and resistance-training exercise, and fall prevention are included in the fracture prevention armamentarium. Where possible, recommendations in this guide are based on evidence from RCTs; however, relevant published data and guidance from expert clinical experience provides the basis for recommendations in those areas where RCT evidence is currently deficient or not applicable to the many osteoporosis patients not considered for RCT participation due to age and morbidity.

Does hip structural analysis confer additional benefit to routine BMD assessment in postmenopausal women with hip fracture? A study from a tertiary center in southern India

This study from southern India showed that proximal hip geometry was significantly impaired in postmenopausal women with femoral neck fracture. The trabecular bone score (TBS), which is reflective of bone microarchitecture, was also significantly impaired in patients with fracture.

INTRODUCTION

There is limited information with regard to comprehensive bone health in Indian postmenopausal women with neck of femur fracture. We studied the bone mineral density (BMD), trabecular bone score (TBS), proximal hip geometry, and bone mineral biochemistry in postmenopausal women with and without femoral neck fractures.

METHODS

This was a cross-sectional study conducted at a tertiary care center in South India. BMD, TBS, and hip structural analysis (HSA) were assessed using a dual-energy X-ray absorptiometry (DXA) scanner. Bone mineral biochemical profiles were also studied.

RESULTS

A total of 90 postmenopausal women with acute femoral neck fracture with mean (SD) age of 63.2 (6.1) years and 90 age-matched controls were included. The prevalence of osteoporosis was higher among cases as compared to controls (83.3% vs 47.8%; P < 0.001). Degraded bone microarchitecture (TBS value < 1.200) was more frequent among women with hip fracture as compared to controls (46.7% vs 31.1%; P = 0.032). Cross-sectional moment of inertia (CSMI) was significantly lower at the narrow neck (NN) and inter-trochanteric (IT) region in cases (P < 0.05) and buckling ratio (BR) was significantly higher at all three sites in postmenopausal women with femoral neck fracture as compared controls. Multivariate logistic regression analysis showed that femoral neck osteoporosis, low CSMI at NN and high BR at NN and femoral shaft emerged as factors significantly associated with femoral neck fractures.

CONCLUSION

This study highlights that impaired parameters of proximal hip geometry and a low trabecular bone score may be significantly associated with femoral neck fractures in postmenopausal women.

Racial and Ethnic Disparities in Bone Health and Outcomes in the United States

Osteoporosis is a bone disease classified by deterioration of bone microarchitecture and decreased bone strength, thereby increasing subsequent risk of fracture. In the United States, approximately 54 million adults aged 50 years and older have osteoporosis or are at risk due to low bone mass. Osteoporosis has long been viewed as a chronic health condition affecting primarily non-Hispanic white (NHW) women; however, emerging evidence indicates racial and ethnic disparities in bone outcomes and osteoporosis management. The primary objective of this review is to describe disparities in bone mineral density (BMD), prevalence of osteoporosis and fracture, as well as in screening and treatment of osteoporosis among non-Hispanic black (NHB), Hispanic, and Asian adults compared with NHW adults living on the US mainland. The following areas were reviewed: BMD, osteoporosis prevalence, fracture prevalence and incidence, postfracture outcomes, DXA screening, and osteoporosis treatments. Although there are limited studies on bone and fracture outcomes within Asian and Hispanic populations, findings suggest that there are differences in bone outcomes across NHW, NHB, Asian, and Hispanic populations. Further, NHB, Asian, and Hispanic populations may experience suboptimal osteoporosis management and postfracture care, although additional population-based studies are needed. There is also evidence that variation in BMD and osteoporosis exists within major racial and ethnic groups, highlighting the need for research in individual groups by origin or background. Although there is a clear need to prioritize future quantitative and qualitative research in these populations, initial strategies for addressing bone health disparities are discussed. © 2021 American Society for Bone and Mineral Research (ASBMR).

Long-term Bone Loss and Deterioration of Microarchitecture After Gastric Bypass in African American and Latina Women

CONTEXT

The prevalence of obesity is burgeoning among African American and Latina women; however, few studies investigating the skeletal effects of bariatric surgery have focused on these groups.

OBJECTIVE

To investigate long-term skeletal changes following Roux-en-Y gastric bypass (RYGB) in African American and Latina women.

DESIGN

Four-year prospective cohort study.

PATIENTS

African American and Latina women presenting for RYGB (n = 17, mean age 44, body mass index 44 kg/m2) were followed annually for 4 years postoperatively.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry (DXA) measured areal bone mineral density (aBMD) at the spine, hip, and forearm, and body composition. High-resolution peripheral quantitative computed tomography measured volumetric bone mineral density (vBMD) and microarchitecture. Individual trabecula segmentation-based morphological analysis assessed trabecular morphology and connectivity.

RESULTS

Baseline DXA Z-Scores were normal. Weight decreased ~30% at Year 1, then stabilized. Parathyroid hormone (PTH) increased by 50% and 25-hydroxyvitamin D was stable. By Year 4, aBMD had declined at all sites, most substantially in the hip. There was significant, progressive loss of cortical and trabecular vBMD, deterioration of microarchitecture, and increased cortical porosity at both the radius and tibia over 4 years. There was loss of trabecular plates, loss of axially aligned trabeculae, and decreased trabecular connectivity. Whole bone stiffness and failure load declined. Risk factors for bone loss included greater weight loss, rise in PTH, and older age.

CONCLUSIONS

African American and Latina women had substantial and progressive bone loss, deterioration of microarchitecture, and trabecular morphology following RYGB. Further studies are critical to understand the long-term skeletal consequences of bariatric surgery in this population.

Hip Structural Analysis Reveals Impaired Hip Geometry in Girls With Type 1 Diabetes

CONTEXT

Among patients with type 1 diabetes (T1D), the risk of hip fracture is up to 6-fold greater than that of the general population. However, the cause of this skeletal fragility remains poorly understood.

OBJECTIVE

To assess differences in hip geometry and imaging-based estimates of bone strength between youth with and without T1D using dual-energy x-ray absorptiometry (DXA)-based hip structural analysis.

DESIGN

Cross-sectional comparison.

PARTICIPANTS

Girls ages 10 to 16 years, including n = 62 with T1D and n = 61 controls.

RESULTS

The groups had similar age, bone age, pubertal stage, height, lean mass, and physical activity. Bone mineral density at the femoral neck and total hip did not differ in univariate comparisons but was lower at the femoral neck in T1D after adjusting for bone age, height, and lean mass. Subjects with T1D had significantly lower cross-sectional area, cross-sectional moment of inertia, section modulus, and cortical thickness at the narrow neck, with deficits of 5.7% to 10.3%. Cross-sectional area was also lower at the intertrochanteric region in girls with T1D. Among those T1D subjects with HbA1c greater than the cohort median of 8.5%, deficits in hip geometry and strength estimates were more pronounced.

CONCLUSIONS

DXA-based hip structural analysis revealed that girls with T1D have unfavorable geometry and lower estimates of bone strength at the hip, which may contribute to skeletal fragility and excess hip fracture risk in adulthood. Higher average glycemia may exacerbate effects of T1D on hip geometry.

Effect of vitamin D on bone strength in older African Americans: a randomized controlled trial

There is controversy over whether African Americans have higher vitamin D requirements than recommended by the Institute of Medicine. We previously reported that maintaining serum 25(OH)D above 30 ng/mL does not prevent age-related bone loss. Herein, we report that bone strength is also unaffected by maintaining this level in this population.

INTRODUCTION

The role of vitamin D in bone strength has not been investigated in the African American (AA) population.

METHODS

A 3-year randomized controlled trial was designed to examine the effect of vitamin D supplementation on physical performance, bone loss, and bone strength in healthy older AA women. A total of 260 postmenopausal AA women, ages ≥ 60 years were randomized to a vitamin D₃ or placebo arm. Vitamin D₃ dose was adjusted to maintain serum 25OHD > 30 ng/mL. Bone mineral density, femoral axis length, and femoral neck (FN) width were measured by dual-energy X-ray absorptiometry. Composite indices of FN strength [compression strength index (CSI), bending strength index (BSI), and impact strength index (ISI)] were computed.

RESULTS

The mean age of participants was 68.2 ± 4.9 years. Baseline characteristics between groups were similar. The average dose of vitamin D₃ was 3490 ± 1465 IU/day in the active group. The mean serum 25OHD was 46.8 ± 1.2 ng/mL versus 20.7 ± 1.1 ng/mL in the active versus placebo group. Serum 25OHD did not correlate with any composite indices. The longitudinal differences observed in FN width, CSI, BSI, and ISI in both groups were not statistically significant (all p values > 0.05). Further, there was no group × time interaction effect for any of the composite indices (all p values > 0.05).

CONCLUSION

Maintaining serum 25OHD > 30 ng/mL (75 nmol/L) does not affect bone strength in older AA women. There is no evidence to support vitamin D intake greater than the recommended RDA by the Institute of Medicine in this population for bone strength.

Effect of surgical and natural menopause on proximal femur morphometry in obese women

The purpose of this study is to determine whether there are differences in proximal femur parameters of women subjected to menopause surgically or naturally. In this study, 10 parameters belonging to proximal femur of a total of 60 women cases of whom 30 had a mean age of 55.53 ± 4.57 years; body mass index, 33.06 ± 4.21 kg/m²; menopause age, 48.10 ± 5.92; and menopause years, 7.50 ± 4.58; and who were subjected to natural menopause; and 30 women whose mean age was 56.10 ± 6.87 years; body mass index, 33.33 ± 3.76 kg/m²; menopause age, 48.00 ± 4.64 years and menopause year, 8.10 ± 7.29; who were subjected to surgical menopause, and who did not use hormone replacement, were examined by radiography. Their anthropometric measurements, body compositions, blood hormone analyses (FSH, LH, estradiol, progesterone) and bone mineral densities (femur neck, femur total, lumbar t-score) were evaluated. It was found that there was no difference between surgical and natural menopause with respect to proximal femur parameters (p > 0.05). It was also found that FSH levels were high in the surgical menopause group and there were significant differences between the groups (p < 0.040). No significant difference was found even though bone mineral density t-score tests were lower in the surgical menopause group (p > 0.05). It was found that the difference in low bone mineral density level and high FSH values in the surgical menopause group do not have a relationship with proximal femur morphometry. It was determined that even though the women did not have ovaries, there was no difference between surgical menopause women and natural menopause women with respect to proximal femur morphometry.

Relationship of American Indian blood quantum with osteoporosis risk: a cross-sectional study of American Indian women in Oklahoma

Information regarding the prevalence and risk of osteoporosis among American Indian (AI) women is limited. This study showed that with increasing AI blood quantum, the prevalence of osteoporosis at the hip based on BMD T-scores decreased and this appeared to be independent of other risk factors.

INTRODUCTION

This study was designed to investigate the effects of AI blood quantum (BQ) on osteoporosis prevalence and risk in a cohort of AI women in Oklahoma.

METHODS

Women (n = 301), aged 50 years and older, were recruited to participate in the Oklahoma American Indian Women's Osteoporosis Study. Baseline bone density, fracture history, bone biochemical markers, and potential risk factors were assessed. Participants were stratified by AI BQ into BQ1 ≤ 25%, BQ2 = 25-49%, BQ3 = 50-74%, and BQ4 = 75-100%. The effects of BQ on the prevalence and risk of osteoporosis were evaluated.

RESULTS

Based on T-scores, one in approximately eight women in the study was osteoporotic at one or more sites. The prevalence of osteoporosis decreased (p < 0.05) with increasing BQ, especially at the hip, trochanteric, and intertrochanter regions. No differences in bone-specific alkaline phosphatase and C-telopeptide were observed across BQ that could account for the differences in bone density. 25-OH vitamin D decreased with increasing BQ, but mean for each BQ1-4 was > 40 ng/mL. Fracture history did not differ across BQ, and though 52% of the population consumed less than the RDA for calcium, no effect of BQ was observed.

CONCLUSIONS

In this cohort of women who identified as AI, greater Indian BQ was associated with a decrease in the prevalence of osteoporosis.

Awareness of osteoporosis in a polytechnic in Enugu, South East Nigeria

This study aims to determine the awareness of osteoporosis and factors that determine awareness of osteoporosis. Results showed that osteoporosis awareness was associated with age (p = 0.006) and occupation (p < 0.001) but not gender, marital status, and level of education. There is therefore need for educational interventions to improve awareness of osteoporosis.

INTRODUCTION

Osteoporosis is a bone disease in which the bone becomes porous, brittle, and more susceptible to fracture. It is the most common metabolic bone disease worldwide. Increased prevalence of disease is attributed to low awareness of disease among general population referred to as a 'silent disease.' There is paucity of evidence of osteoporosis awareness in Africa while level of knowledge in Nigeria is also minimal.

METHODS

The study was carried out in a Polytechnic in Enugu, South East Nigeria, as one of the phases of ongoing awareness exercise on osteoporosis. Study design was descriptive cross-sectional study using stratified random sampling method for selection. The study made use of a structured, self-administered questionnaire using English language. Statistical analyses were carried out with SPSS version 22 software, using Chi square and Fischer exact tests of significance and alpha level set at p = 0.05.

RESULTS

Out of a total number of 500 respondents, 187 (37.4%) had heard about osteoporosis, however, only 34 (18.2%) of those who have heard about osteoporosis knew the correct meaning of osteoporosis. Overall, only 34 (6.8%) out of 500 knew the correct meaning of osteoporosis. Osteoporosis awareness was highest among age group ≥51 years (33.3%) and least in age group ≤20 years (6.3%) (p = 0.006). Awareness was also highest among civil servants (17.9%) and least among unemployed respondents (0.0%) (p < 0.001). There was no gender preponderance in awareness level while marital status and level of education were not significantly associated with level of awareness.

CONCLUSION

While there was low knowledge of osteoporosis in the study area, awareness of osteoporosis was associated with age and occupation but not gender, marital status, or level of education. There is need for educational interventions to improve awareness of osteoporosis.

Differences in femoral neck structure between elderly Caucasian and Chinese populations: a cross-sectional study of Perth-Beijing cohorts

Structural skeletal differences of the femoral neck of older Beijing-Chinese and Perth-Caucasian women were compared; adjusting for frame size-related differences, Beijing-Chinese have lower periosteal width; however, indices of internal bone distribution suggest that Beijing-Chinese may exhibit increased resistance to fracture that may relate to the reduced hip fracture incidence.

INTRODUCTION

Ethnic differences in skeletal structure may relate to differences in hip fracture risk in Chinese and Caucasian populations. 2D mass, size, and structural biomechanics were compared in the two populations.

METHODS

Quantitative computed tomography-derived geometric variables were compared in age-matched community-derived female populations, 196 Beijing-Chinese 76.5 ± 4.8 (mean ± SD) years and 237 Perth-Caucasians 77.1 ± 5.0 years. These included scanned area (A), periosteal width (W), bone mineral content (BMC), aBMD, bone cross-sectional area (bCSA), section modulus (Z) and buckling ratio (BR). Assumption-free measures included sigma (σ), related to the distribution of bone in the scanned image previously identified as a predictor of hip fracture, and delta (δ), the center-of-mass displacement from the geometric center.

RESULTS

Compared to Beijing-Chinese, Perth-Caucasians were heavier (Beijing-Chinese 58.7 ± 11.8; Perth-Caucasians 66.1 ± 11.0 kg), taller (154.9 ± 16.7 vs 158.9 ± 6.0 cm), and had higher BMC, A, and W. After adjustment for frame size, BMC was not significantly different but W remained higher in Perth-Caucasians. Differences in variables aBMD, Z, BR, and σ favored higher resistance to failure with Beijing-Chinese before and after adjustment for frame size. δ was similar in both populations; bCSA was higher in Beijing-Chinese before adjustment for frame size but not after.

CONCLUSIONS

Bone mass differences in two populations were related to frame size differences. However, femoral neck width remained smaller in Beijing-Chinese suggesting effects of local genetic and environmental factors. In Beijing-Chinese participants compared to Perth-Caucasians, internal bone distribution suggests increased resistance to deformation if exposed to same force that may, in-part, relate to reduced incidence of hip fracture in Beijing-Chinese.

Spatial Differences in the Distribution of Bone Between Femoral Neck and Trochanteric Fractures

There is little knowledge about the spatial distribution differences in volumetric bone mineral density and cortical bone structure at the proximal femur between femoral neck fractures and trochanteric fractures. In this case-control study, a total of 93 women with fragility hip fractures, 72 with femoral neck fractures (mean ± SD age: 70.6 ± 12.7 years) and 21 with trochanteric fractures (75.6 ± 9.3 years), and 50 control subjects (63.7 ± 7.0 years) were included for the comparisons. Differences in the spatial distributions of volumetric bone mineral density, cortical bone thickness, cortical volumetric bone mineral density, and volumetric bone mineral density in a layer adjacent to the endosteal surface were investigated using voxel-based morphometry (VBM) and surface-based statistical parametric mapping (SPM). We compared these spatial distributions between controls and both types of fracture, and between the two types of fracture. Using VBM, we found spatially heterogeneous volumetric bone mineral density differences between control subjects and subjects with hip fracture that varied by fracture type. Interestingly, femoral neck fracture subjects, but not subjects with trochanteric fracture, showed significantly lower volumetric bone mineral density in the superior aspect of the femoral neck compared with controls. Using surface-based SPM, we found that compared with controls, both fracture types showed thinner cortices in regions in agreement with the type of fracture. Most outcomes of cortical and endocortical volumetric bone mineral density comparisons were consistent with VBM results. Our results suggest: 1) that the spatial distribution of trabecular volumetric bone mineral density might play a significant role in hip fracture; 2) that focal cortical bone thinning might be more relevant in femoral neck fractures; and 3) that areas of reduced cortical and endocortical volumetric bone mineral density might be more relevant for trochanteric fractures in Chinese women. © 2017 American Society for Bone and Mineral Research.

Fractures in indigenous compared to non-indigenous populations: A systematic review of rates and aetiology

BACKGROUND

Compared to non-indigenous populations, indigenous populations experience disproportionately greater morbidity, and a reduced life expectancy; however, conflicting data exist regarding whether a higher risk of fracture is experienced by either population. We systematically evaluate evidence for whether differences in fracture rates at any skeletal site exist between indigenous and non-indigenous populations of any age, and to identify potential risk factors that might explain these differences.

METHODS

On 31 August 2016 we conducted a comprehensive computer-aided search of peer-reviewed literature without date limits. We searched PubMed, OVID, MEDLINE, CINAHL, EMBASE, and reference lists of relevant publications. The protocol for this systematic review is registered in PROSPERO, the International Prospective Register of systematic reviews (CRD42016043215). Using the World Health Organization reference population as standard, hip fracture incidence rates were re-standardized for comparability between countries.

RESULTS

Our search yielded 3227 articles; 283 potentially eligible articles were cross-referenced against predetermined criteria, leaving 27 articles for final inclusion. Differences in hip fracture rates appeared as continent-specific, with lower rates observed for indigenous persons in all countries except for Canada and Australia where the opposite was observed. Indigenous persons consistently had higher rates of trauma-related fractures; the highest were observed in Australia where craniofacial fracture rates were 22-times greater for indigenous compared to non-indigenous women. After adjustment for socio-demographic and clinical risk factors, approximately a three-fold greater risk of osteoporotic fracture and five-fold greater risk of craniofacial fractures was observed for indigenous compared to non-indigenous persons; diabetes, substance abuse, comorbidity, lower income, locality, and fracture history were independently associated with an increased risk of fracture.

CONCLUSIONS

The observed paucity of data and suggestion of continent-specific differences indicate an urgent need for further research regarding indigenous status and fracture epidemiology and aetiology. Our findings also have implications for communities, governments and healthcare professionals to enhance the prevention of trauma-related fractures in indigenous persons, and an increased focus on modifiable lifestyle behaviours to prevent osteoporotic fractures in all populations.

Gender differences in a reference database of age-related femoral neck geometric parameters for Chinese population and their association with femoral neck fractures

Femoral neck geometric parameters (FNGPs) are closely related to the strength of the femoral neck and the risk of fragility fractures. No reference database is available for FNGPs for Chinese population, and gender-related differences in FNGPs as well as their association with the risk of femoral neck fractures are unknown. This investigation aimed to set up reference databases for FNGPs, understand gender-related differences in FNGPs, and examine the association between FNGPs and the risk of osteoporotic fractures of the femoral neck. This study included 5268 females and 2156 males (aged 15-91years) from Chinese population. A total of 384 patients (282 females and 102 males) had sustained femoral neck fractures; 384 age- and sex-matched individuals without any fractures served as controls. Femoral neck DXA images were used to measure bone mineral density (BMD) and eight FNGPs. Our results showed that the age-related trends of FNGPs were fitted with the best goodness-of-fit by applying the cubic regression model. The trends shown by FNGPs were significantly different between male and female subjects, and the fitting curves were significantly higher in male subjects. After adjustments were made for age, height, weight, and body mass index, Cox regression analysis showed that changes in all FNGPs were related to increased hazard ratios (HRs) of femoral neck fractures. After further adjustment was made for BMD of the femoral neck, the HRs related to a cortical thickness (CT) decrease and buckling ratio (BR) increase in females went up by 3.35-folds (95% CI: 2.75-4.07) and 1.86-folds (95% CI: 1.33-2.60), respectively. In males, the HRs related to the decrease in CT and cross-sectional area (CSA) increased by 3.21-folds (95% CI: 2.32-4.45) and 1.88-folds (95% CI: 1.03-3.44), respectively. In conclusions, the reference databases of FNGPs established in this study will assist in the evaluation and prediction of femoral neck fracture risk in the clinic. The decrease in CT and increase in BR of the femoral neck were independent risk factors for osteoporotic fractures of the femoral neck in females from mainland China, while a decrease in CT and CSA were risk factors in male.

Higher serum ferritin level and lower femur neck strength in women at the stage of bone loss (≥ 45 years of age): The Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV)

PURPOSE

Despite the clear effect of iron on bone metabolism, most clinical studies related to bone health have only focused on bone mineral density (BMD). In the present study, we investigated the relationship between serum ferritin and composite indices of femur neck strength via a population-based, cross-sectional study using the Korea National Health and Nutrition Examination Survey (KNHANES).

METHODS

Our study series included 693 women at the stage of bone loss (≥ 45 years of age), defined based on the observed patterns of age-related BMD changes in the KNHANES. Geometric bone structure properties, including hip axis length (HAL) and femur neck width (FNW), were measured using hip dual-energy X-ray absorptiometry scans and were combined with BMD, body weight, and height to create composite indices of femur neck strength relative to load in three different failure modes: compression (CSI), bending (BSI), and impact strength indices (ISI).

RESULTS

After adjustment for age, body mass index (BMI), lifestyle factors, serum 25-hydroxyvitamin D, calcium and phosphorus intake, diabetes, and menopause status, multiple regression analyses revealed that serum ferritin was inversely associated with the BMD values at the lumbar spine and femur neck, and the femur neck cortical thickness. Importantly, in all adjustment models, higher serum ferritin was consistently associated with the lower values for all three femur neck composite indices, such as CSI, BSI, and ISI.

CONCLUSIONS

These data provide the first clinical evidence that increased total body iron stores reflected by higher serum ferritin may be associated with the decrease of bone strength relative to load.

Evaluating the relationship between muscle and bone modeling response in older adults

Bone modeling, the process that continually adjusts bone strength in response to prevalent muscle-loading forces throughout an individual's lifespan, may play an important role in bone fragility with age. Femoral stress, an index of bone modeling response, can be estimated using measurements of DXA derived bone geometry and loading information incorporated into an engineering model. Assuming that individuals have adapted to habitual muscle loading forces, greater stresses indicate a diminished response and a weaker bone. The purpose of this paper was to evaluate the associations of lean mass and muscle strength with the femoral stress measure generated from the engineering model and to examine the extent to which lean mass and muscle strength account for variation in femoral stress among 2539 healthy older adults participating in the Health ABC study using linear regression. Mean femoral stress was higher in women (9.51, SD=1.85Mpa) than in men (8.02, SD=1.43Mpa). Percent lean mass explained more of the variation in femoral stress than did knee strength adjusted for body size (R(2)=0.187 vs. 0.055 in men; R(2)=0.237 vs. 0.095 in women). In models adjusted for potential confounders, for every percent increase in lean mass, mean femoral stress was 0.121Mpa lower (95% CI: -0.138, -0.104; p<0.001) in men and 0.139Mpa lower (95% CI: -0.158, -0.121; p<0.001) in women. The inverse association of femoral stress with lean mass and with knee strength did not differ by category of BMI. Results from this study provide insight into bone modeling differences as measured by femoral stress among older men and women and indicate that lean mass may capture elements of bone's response to load.

Proximal Femoral Geometry as Fracture Risk Factor in Female Patients with Osteoporotic Hip Fracture

Background

Proximal femoral geometry may be a risk factor of osteoporotic hip fractures. However, there existed great differences among studies depending on race, sex and age of subjects. The purpose of the present study is to analyze proximal femoral geometry and bone mineral density (BMD) in the osteoporotic hip fracture patients. Furthermore, we investigated proximal femoral geometric parameters affecting fractures, and whether the geometric parameters could be an independent risk factor of fractures regardless of BMD.

Methods

This study was conducted on 197 women aged 65 years or more who were hospitalized with osteoporotic hip fracture (femur neck fractures ; 84, intertrochanteric fractures; 113). Control group included 551 women who visited to check osteoporosis. Femur BMD and proximal femoral geometry for all subjects were measured using dual energy X-ray absorptiometry (DXA), and compared between the control and fracture groups. Besides, proximal femoral geometric parameters associated with fractures were statistically analyzed.

Results

There were statistically significant differences in the age and weight, cross-sectional area (CSA)/length/width of the femoral neck and BMD of the proximal femur between fracture group and control group. BMD of the proximal femur in the control group was higher than in the fracture group. For the femoral neck fractures group, the odds ratio (OR) for fractures decrease in the CSA and neck length (NL) of the femur increased by 1.97 times and 1.73 times respectively, regardless of BMD. The OR for fractures increase in the femoral neck width increased by 1.53 times. In the intertrochanteric fracture group, the OR for fractures increase in the femoral neck width increased by 1.45 times regardless of BMD.

Conclusions

We found that an increase of the femoral neck width could be a proximal femoral geometric parameter which plays important roles as a risk factor for fracture independently of BMD.

Physical Functioning Among Women Aged 80 Years and Older With Previous Fracture

BACKGROUND

The oldest old are the fastest growing segment of the elderly population. Little is known regarding the associations of fracture history with physical functioning assessed after age 80.

METHODS

Among 33,386 women surviving to age 80 years (mean ± SD years 84.6 ± 3.4), we examined the relationship between history of incident fracture after entry into the Women's Health Initiative (follow-up 15.2 ± 1.3 years) and their physical functioning assessed using the RAND-36 instrument most proximal to 2012 end of follow-up.

RESULTS

Baseline mean (±SD) physical function score was 82 (± 18). After adjustment for demographic and medical characteristics, fracture at each site, including hip, upper limb, lower limb, and central body, was associated with significantly lower subsequent physical functioning (all p < .001). Hip, upper leg, spine, and pelvis fractures were particularly related with lower physical functioning scores, 11.7 (95% CI: 10.3, 13.1), 10.5 (8.8, 12.3), 9.8 (8.9, 10.8), and 8.7 (7.2, 10.2) units lower, respectively, compared with women without fracture (each p < .0001). Compared with women without central site fracture, women with central site fractures also had lower physical functioning scores (10.0 [9.3, 10.8] units lower]; p < .0001). In case-only analysis of fractures, older age, less than 1 year since fracture, one or more additional sites fractured, history of cardiovascular disease or cancer, higher body mass index, and no alcohol intake in the past 3 months also were independent predictors of lower physical functioning score (all p < .05).

CONCLUSIONS

Among women surviving to 80 years and older, prior fracture is associated with lower current physical functioning, regardless of anatomical site of fracture, independent of other major predictors of disability.

Cortical bone histomorphology of known-age skeletons from the Kirsten collection, Stellenbosch university, South Africa

Objectives

Normal human bone tissue changes predictably as adults get older, but substantial variability in pattern and pace remains unexplained. Information is needed regarding the characteristics of histological variables across diverse human populations.

Methods

Undecalcified thin sections from mid‐thoracic ribs of 213 skeletons (138 M, 75 F, 17–82 years, mean age 48 years), are used to explore the efficacy of an established age‐at‐death estimation method and methodological approach (Cho et al.: J Forensic Sci 47 (2002) 12‐18) and expand on it. The ribs are an age‐balanced sample taken from skeletonized cadavers collected from 1967 to 1999 in South Africa, each with recorded sex, age, cause of death and government‐defined population group (129 “Colored,” 49 “Black,” 35 “White”).

Results

The Ethnicity Unknown equation performs better than those developed for European‐Americans and African‐Americans, in terms of accuracy and bias. A new equation based solely on the study sample does not improve accuracy. Osteon population densities (OPD) show predicted values, yet secondary osteon areas (On.Ar) are smaller than expected for non‐Black subgroups. Relative cortical area (Ct.Ar/Tt.Ar) is low among non‐Whites.

Conclusions

Results from this highly diverse sample show that population‐specific equations do not increase estimate precision. While within the published range of error for the method (±24.44 years), results demonstrate a systematic under‐aging of young adults and over‐aging of older adults. The regression approach is inappropriate. The field needs fresh approaches to statistical treatment and to factors behind cortical bone remodeling. Am J Phys Anthropol 160:137–147, 2016. © 2016 The Authors American Journal of Physical Anthropology Published by Wiley Periodicals, Inc.

The femoral neck-shaft angle on plain radiographs: a systematic review

OBJECTIVE

The femoral neck-shaft angle (NSA) is an important measure for the assessment of the anatomy of the hip and planning of operations. Despite its common use, there remains disagreement concerning the method of measurement and the correction of hip rotation and femoral version of the projected NSA on conventional radiographs. We addressed the following questions: (1) What are the reported values for NSA in normal adult subjects and in osteoarthritis? (2) Is there a difference between non-corrected and rotation-corrected measurements? (3) Which methods are used for measuring the NSA on plain radiographs? (4) What could be learned from an analysis of the intra- and interobserver reliability?

MATERIAL AND METHODS

A systematic literature search was performed including 26 publications reporting the measurement of the NSA on conventional radiographs.

RESULTS

The mean NSA of healthy adults (5,089 hips) was 128.8° (98-180°) and 131.5° (115-155°) in patients with osteoarthritis (1230 hips). The mean NSA was 128.5° (127-130.5°) for the rotation-corrected and 129.5° (119.6-151°) for the non-corrected measurements.

CONCLUSION

Our data showed a high variance of the reported neck-shaft angles. Notably, we identified the inconsistency of the published methods of measurement as a central issue. The reported effect of rotation-correction cannot be reliably verified.

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 hip structure analysis method and that of the similar GE, Madison, WI, algorithm Advanced Hip Analysis use both the dimensional information and the mineral mass data to compute the types of dimensional properties (i.e., geometry) that are used to evaluate mechanical strength in engineering analyses. This article describes the hip structure analysis method and a somewhat cruder geometry approximation that does not require a reanalysis of the image. Limitations of the methods are discussed.

Intraskeletal Variability of Relative Cortical Area in Humans

Histomorphometric and cross-sectional geometric studies of bone have provided valuable information about age at death, behavioral and activity patterns, and pathological conditions for past and present human populations. While a considerable amount of exploratory and applied research has been completed using histomorphometric and cross-sectional geometric properties, the effects of intraskeletal variability on interpreting observed histomorphometric data have not been fully explored. The purpose of this study is to quantify intraskeletal variability in the relative cortical area of long bones and ribs from modern humans. To examine intraskeletal variability, cross-sections of the femur, tibia, fibula, humerus, radius, ulna, and rib when present, were examined within individuals from a cadaveric collection (N = 34). Relative cortical area was compared within individuals using a repeated measurements General Linear Model, which shows significant differences between bones, particularly between the rib and the remaining long bones. Complementarily, correlations between bones' relative cortical area values suggest an important allometric component affecting this aspect of long bones, but not of the rib. This study highlights the magnitude of intraskeletal variability in relative cortical area in the human skeleton, and because the relative cortical area of any particular bone is affected by a series of confounding factors, extrapolation of relative cortical area values to infer load history for other skeletal elements can be misleading.

Low skeletal muscle mass associates with low femoral neck strength, especially in older Korean women: the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV)

SUMMARY

Data gathered from a nationally representative cohort demonstrated that subject with low skeletal muscle mass had consistently low femoral neck composite strength indices for compression, bending, and impact, especially in older women, supporting the highly integrated nature of skeletal muscle and bone.

INTRODUCTION

Skeletal muscle and bone interact mechanically and functionally. The present study was performed to investigate the association between muscle mass and femoral neck composite strength indices using a nationally representative cohort.

METHODS

This is a population-based, cross-sectional study from Korea National Health and Nutrition Examination Surveys, including 1,275 Koreans (674 women and 601 men) aged 50 years or older. Femoral neck axis length and width were measured by hip DXA scans and were combined with BMD, body weight, and height to create composite indices of femoral neck strength relative to load in three different failure modes: compression, bending, and impact. Presarcopenia was defined as an appendicular skeletal muscle mass (ASM) divided by body weight that was less than 1 SD below the sex-specific mean for young adults.

RESULTS

After adjusting for confounders, women with presarcopenia had consistently lower indices for compression strength (CSI), bending strength (BSI), and impact strength (ISI) than women without this condition. Men with presarcopenia had a lower ISI value than men without presarcopenia. Multiple regression analyses revealed that lower relative skeletal muscle mass (ASM/weight) associated significantly with lower values for all three femoral neck composite indices in women and with lower CSI and ISI in men.

CONCLUSIONS

These findings provide the first clinical evidence for the notion that age-related low muscle mass may increase the risk of osteoporotic hip fractures by decreasing femoral neck strength relative to load, especially in older women, and support the highly integrated nature of skeletal muscle and bone.

Ethnic differences in bone health

There are differences in bone health between ethnic groups in both men and in women. Variations in body size and composition are likely to contribute to reported differences. Most studies report ethnic differences in areal bone mineral density (aBMD), which do not consistently parallel ethnic patterns in fracture rates. This suggests that other parameters beside aBMD should be considered when determining fracture risk between and within populations, including other aspects of bone strength: bone structure and microarchitecture, as well as muscle strength (mass, force generation, anatomy) and fat mass. We review what is known about differences in bone-densitometry-derived outcomes between ethnic groups and the extent to which they account for the differences in fracture risk. Studies are included that were published primarily between 1994 and 2014. A "one size fits all approach" should definitely not be used to understand better ethnic differences in fracture risk.

Bone density, microarchitecture and stiffness in Caucasian and Caribbean Hispanic postmenopausal American women

Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aimed to compare Caucasian and Caribbean Hispanic postmenopausal American women with respect to these characteristics. Thirty-three Caribbean Hispanics were age-matched to thirty-three Caucasian postmenopausal women. At the lumbar spine, the Hispanic women had significantly lower areal bone mineral density (aBMD). At the radius by high-resolution peripheral quantitative computed tomography (HR-pQCT), there were minimal differences between Hispanic and Caucasian women. At the tibia, Hispanic women had lower trabecular volumetric bone density and trabecular number, and higher trabecular separation. Individual trabecula segmentation (ITS) analyses indicated that at the tibia, Hispanic women not only had significantly lower bone volume fraction, but also had significantly lower rod bone volume fraction, plate trabecular number, rod trabecular number and lower plate–plate, plate–rod and rod–rod junction densities compared to Caucasian women. The differences in bone quantity and quality contributed to lower whole bone stiffness at the radius, and both whole bone and trabecular bone stiffness at the tibia in Hispanic women. In conclusion, Hispanic women had poorer bone mechanical and microarchitectural properties than Caucasian women, especially at the load-bearing distal tibia.

Race/ethnic differences in associations between bone mineral density and fracture history in older men

SUMMARY

To determine whether there are race/ethnic differences in bone mineral density (BMD) by fracture history in men aged 65 years and older, we performed cross-sectional analysis in five large independent cohorts. Low BMD was associated with a higher prevalence of fracture in all cohorts, and the magnitude of the BMD differences by fracture status was similar across groups.

INTRODUCTION

We aimed to determine whether there are race/ethnic and geographic differences in bone mineral density by fracture history in men aged 65 years and older.

METHOD

The datasets included the Osteoporotic Fractures in Men (MrOS) Study (5,342 White, 243 African-American, 190 Asian, and 126 Hispanic), MrOS Hong Kong (1,968 Hong Kong Chinese), Tobago Bone Health Study (641 Afro-Caribbean), Namwon Study (1,834 Korean), and Dong-gu Study (2,057 Korean). The two Korean cohorts were combined.

RESULTS

The prevalence of self-reported non-traumatic fracture was US white, 17.1 %; Afro-Caribbean, 5.5 %; US African-American, 15.1 %; US Hispanic, 13.7 %; US Asian, 10.5 %; Hong Kong Chinese, 5.6 %, and Korean, 5.1 %. The mean differences in hip and lumbar spine BMD between subjects with fracture and without fracture were statistically significant in all cohorts except US African American and US Asian men. There was a significant race/ethnic interaction for lumbar spine BMD by fracture status (p for interaction = 0.02), which was driven by the small number of Hispanic men. There was no interaction for femoral neck or total hip BMD. There were no significant race/ethnic differences in the odds ratio of fracture by BMD.

CONCLUSIONS

Low BMD was associated with a higher prevalence of fracture in all cohorts and the magnitude of the BMD differences by fracture status was similar across groups suggesting homogeneity in the BMD-fracture relationship among older men.

Risk factors for fracture in middle-age and older-age men of African descent

Although fracture rates are lower in individuals of African descent compared to individuals of European ancestry, morbidity and mortality following a fracture may be greater in individuals of African ancestry. However, fracture risk and associated clinical risk factors have not been well-defined among African ancestry populations, especially among men of African ancestry. We used data collected from the Tobago Bone Health Study to examine potential clinical risk factors for incident fractures, including demographic information, anthropometric measurements, medical history, lifestyle factors, bone mineral density (BMD), and hip structural geometry. Among 1933 Afro-Caribbean men aged ≥40 years at study entry (mean age: 57.2 ± 11.0 years), 65 reported at least one new fracture during 10 years of subsequent follow-up. Younger age, mixed Afro-Caribbean ancestry, prior fracture history, BMD, and hip structural geometry were statistically significant risk factors for incident fractures. A 1-SD change in several skeletal parameters (hip BMD, cross-sectional area, outer diameter, cortical thickness, and buckling ratio) were each associated with a 35% to 56% increase in incident fracture risk after adjusting for age. Men with a prior fracture history were three times more likely to experience a new fracture during follow-up, and the association remained strong after adjusting for age, mixed Afro-Caribbean ancestry, and skeletal parameters (hazard ratios ranged from 2.72 to 2.82). Our findings suggest that except for age, risk factors for fracture in men of African ancestry are similar to established risk factors in white populations. Prior fracture history is a powerful and independent risk factor for incident fractures among men of African ancestry and could easily be incorporated into clinical risk evaluation.

[Ethnicity and vitamin D]

Cohort studies, mainly US, show that vitamin D deficiency is more common in African-American population. Social and environmental factors play a role but the difference in skin color is essential. Despite low 25-hydroxyvitamin D concentrations, a lower risk of fragility or fracture exists in these populations. Vitamin D deficiency is a contributing factor in many chronic diseases. There is a relationship between vitamin D deficiencies, progression of chronic kidney disease and increased relative risk of mortality. If the ethnicity of patients is now taken into account to estimate renal function, probably specific recommendations for vitamin D deficiency are needed.

Ethnic variability in bone geometry as assessed by hip structure analysis: findings from the hip strength across the menopausal transition study

Racial/ethnic origin plays an important role in fracture risk. Racial/ethnic differences in fracture rates cannot be fully explained by bone mineral density (BMD). Studies examining the influence of bone geometry and strength on fracture risk have focused primarily on older adults and have not included people from diverse racial/ethnic backgrounds. Our goal was to explore racial/ethnic differences in hip geometry and strength in a large sample of midlife women. We performed hip structure analysis (HSA) on hip dual-energy X-ray absorptiometry (DXA) scans from 1942 premenopausal and early perimenopausal women. The sample included white (50%), African American (27%), Chinese (11%), and Japanese (12%) women aged 42 to 52 years. HSA was performed using software developed at Johns Hopkins University. African American women had higher conventional (8.4% to 9.7%) and HSA BMD (5.4% to 19.8%) than other groups with the exception being Japanese women, who had the highest HSA BMD (9.7% to 31.4%). HSA indices associated with more favorable geometry and greater strength and resistance to fracture were more prevalent in African American and Japanese women. Femurs of African American women had a smaller outer diameter, a larger cross-sectional area and section modulus, and a lower buckling ratio. Japanese women presented a different pattern with a higher section modulus and lower buckling ratio, similar to African American women, but a wider outer diameter; this was offset by a greater cross-sectional area and a more centrally located centroid. Chinese women had similar conventional BMD as white women but a smaller neck region area and HSA BMD at both regions. They also had a smaller cross-sectional area and section modulus, a more medially located centroid, and a higher buckling ratio than white women. The observed biomechanical differences may help explain racial/ethnic variability in fracture rates. Future research should explore the contribution of hip geometry to fracture risk across all race/ethnicities.

Hip geometry in diabetic women: implications for fracture risk

OBJECTIVE

Women with type 2 diabetes mellitus (T2DM) have a higher risk of fractures despite increased bone mineral density (BMD) as compared to women without diabetes. We hypothesized that bone strength is diminished in women with T2DM after accounting for lean body mass, which may contribute to their increased fracture risk.

METHODS

Participants from Women's Health Initiative Observational Study were included in this cross-sectional study. These analyses include 3 groups of women: 1) T2DM women on diet or oral hypoglycemic agents (n=299); 2) T2DM women on insulin therapy (with or without oral agents) (n=128); and 3) Non-diabetic control women (n=5497). Hip structural analyses were done using the validated Beck's method on hip scans from dual energy x-ray absorptiometry (DXA). We compared BMD and section modulus (bending strength) at the narrow neck with and without correcting for total body DXA lean body mass.

RESULTS

Women in all three groups were of similar ages (63.7, 64.6 and 64.2 years, respectively) and heights, but those with T2DM were heavier, with greater lean body weight vs controls (P<.001). In both diabetic groups, absolute BMD and section modulus were higher compared with controls. However, after adjusting for total lean body weight, diabetic women on insulin had significantly lower BMD and section modulus.

CONCLUSION

Adjusted for lean body weight, the BMD and bending strength in the femoral neck are significantly lower in insulin-treated diabetic women vs controls. This may represent altered adaptation of bone modeling and explain the higher fracture risk in patients with T2DM.

Fracture risk assessment without race/ethnicity information

CONTEXT

Dual-energy x-ray absorptiometry-derived bone mineral density (BMD) does not explain interracial differences in fracture risk; thus, BMD-based fracture risk assessment requires patient race/ethnicity information and ethnicity-specific BMD reference databases.

OBJECTIVE

The objective of the study was to investigate whether composite femoral neck strength indices, which integrate dual-energy x-ray absorptiometry-derived femoral neck size, femoral neck BMD, and body size, will allow fracture risk assessment without requiring race/ethnicity information.

DESIGN

This was a prospective cohort study.

SETTING AND PARTICIPANTS

A total of 1940 community-dwelling women aged 42-53 yr from four race/ethnicity groups (968 Caucasian, 512 African-American, 239 Japanese, and 221 Chinese) were followed up for 9 yr.

OUTCOME MEASUREMENTS

Self-reported, nondigital, noncraniofacial fractures were measured.

RESULTS

Two hundred and two women (10.4%) sustained fractures and 82 (4.3%) had minimum-trauma fractures. Each sd increment in any of the strength indices was associated with a 34-41% reduction in fracture hazard over 9 yr (each P<0.001). Race/ethnicity predicted fracture hazard independent of BMD (P=0.02) but did not predict fracture hazard independent of any of the composite indices (P=0.11-0.22). Addition of race/ethnicity did not improve risk discrimination ability of the strength indices, but did significantly improve the discrimination ability of BMD. The discrimination ability of BMD with race/ethnicity was not statistically different from that of any of the strength indices without race/ethnicity.

CONCLUSIONS

Composite strength indices of the femoral neck can predict fracture risk without race/ethnicity information as accurately as bone mineral density does in combination with race/ethnicity information and therefore would allow risk prediction in people of mixed race/ethnicity and in groups without a BMD reference database.

Health disparities in endocrine disorders: biological, clinical, and nonclinical factors--an Endocrine Society scientific statement

OBJECTIVE

The aim was to provide a scholarly review of the published literature on biological, clinical, and nonclinical contributors to race/ethnic and sex disparities in endocrine disorders and to identify current gaps in knowledge as a focus for future research needs. PARTICIPANTS IN DEVELOPMENT OF SCIENTIFIC STATEMENT: The Endocrine Society's Scientific Statement Task Force (SSTF) selected the leader of the statement development group (S.H.G.). She selected an eight-member writing group with expertise in endocrinology and health disparities, which was approved by the Society. All discussions regarding the scientific statement content occurred via teleconference or written correspondence. No funding was provided to any expert or peer reviewer, and all participants volunteered their time to prepare this Scientific Statement.

EVIDENCE

The primary sources of data on global disease prevalence are from the World Health Organization. A comprehensive literature search of PubMed identified U.S. population-based studies. Search strategies combining Medical Subject Headings terms and keyword terms and phrases defined two concepts: 1) racial, ethnic, and sex differences including specific populations; and 2) the specific endocrine disorder or condition. The search identified systematic reviews, meta-analyses, large cohort and population-based studies, and original studies focusing on the prevalence and determinants of disparities in endocrine disorders. consensus process: The writing group focused on population differences in the highly prevalent endocrine diseases of type 2 diabetes mellitus and related conditions (prediabetes and diabetic complications), gestational diabetes, metabolic syndrome with a focus on obesity and dyslipidemia, thyroid disorders, osteoporosis, and vitamin D deficiency. Authors reviewed and synthesized evidence in their areas of expertise. The final statement incorporated responses to several levels of review: 1) comments of the SSTF and the Advocacy and Public Outreach Core Committee; and 2) suggestions offered by the Council and members of The Endocrine Society.

CONCLUSIONS

Several themes emerged in the statement, including a need for basic science, population-based, translational and health services studies to explore underlying mechanisms contributing to endocrine health disparities. Compared to non-Hispanic whites, non-Hispanic blacks have worse outcomes and higher mortality from certain disorders despite having a lower (e.g. macrovascular complications of diabetes mellitus and osteoporotic fractures) or similar (e.g. thyroid cancer) incidence of these disorders. Obesity is an important contributor to diabetes risk in minority populations and to sex disparities in thyroid cancer, suggesting that population interventions targeting weight loss may favorably impact a number of endocrine disorders. There are important implications regarding the definition of obesity in different race/ethnic groups, including potential underestimation of disease risk in Asian-Americans and overestimation in non-Hispanic black women. Ethnic-specific cut-points for central obesity should be determined so that clinicians can adequately assess metabolic risk. There is little evidence that genetic differences contribute significantly to race/ethnic disparities in the endocrine disorders examined. Multilevel interventions have reduced disparities in diabetes care, and these successes can be modeled to design similar interventions for other endocrine diseases.

Increased bone mineral density in Aboriginal and Torres Strait Islander Australians: impact of body composition differences

Bone mineral density (BMD) has been reported to be both higher and lower in Indigenous women from different populations. Body composition data have been reported for Indigenous Australians, but there are few published BMD data in this population. We assessed BMD in 161 Indigenous Australians, identified as Aboriginal (n=70), Torres Strait Islander (n=68) or both (n=23). BMD measurements were made on Norland-XR46 (n=107) and Hologic (n=90) dual-energy X-ray absorptiometry (DXA) machines. Norland BMD and body composition measurements in these individuals, and also in 36 Caucasian Australians, were converted to equivalent Hologic BMD (BMD(H)) and body composition measurements for comparison. Femoral neck (FN) and lumbar spine Z-scores were high in Indigenous participants (mean FN Z-score: Indigenous men +0.98, p<0.0001 vs. mean zero; Indigenous women +0.82, p<0.0001 vs. mean zero). FN BMD(H) was higher in Aboriginal and/or Torres Strait Islander than Caucasian participants, after adjusting for age, gender, diabetes and height and remained higher in men after addition of lean mass to the model. We conclude that FN BMD is higher in Aboriginal and/or Torres Strait Islander Australians than Caucasian Australian reference ranges and these differences still remained significant in men after adjustment for lean mass. It remains to be seen whether these BMD differences translate to differences in fracture rates.

Dual-energy X-ray performs as well as clinical computed tomography for the measurement of visceral fat

Visceral adipose tissue (VAT) is associated with adverse health effects including cardiovascular disease and type 2 diabetes. We developed a dual-energy X-ray absorptiometry (DXA) measurement of visceral adipose tissue (DXA-VAT) as a low cost and low radiation alternative to computed tomography (CT). DXA-VAT was compared to VAT assessed using CT by an expert reader (E-VAT). In addition, the same CT slice was also read by a clinical radiographer (C-VAT) and a best-fit anthropomorphic and demographic VAT model (A-VAT) was developed. Whole body DXA, CT at L4-L5, and anthropometry were measured on 272 black and white South African women (age 29 ± 8 years, BMI 28 ± 7 kg/m(2), waist circumference (WC) 89 ± 16 cm). Approximately one-half of the dataset (n = 141) was randomly selected and used as a training set for the development of DXA-VAT and A-VAT, which were then used to estimate VAT on the remaining 131 women in a blinded fashion. DXA-VAT (r = 0.93, standard error of the estimate (SEE) = 16 cm(2)) and C-VAT (r = 0.93, SEE = 16 cm(2)) were strongly correlated to E-VAT. These correlations with E-VAT were significantly stronger (P < 0.001) than the correlations of individual anthropometry measurements and the A-VAT model (WC + age, r = 0.79, SEE = 27 cm(2)). The inclusion of anthropometric and demographic measurements did not substantially improve the correlation between DXA-VAT and E-VAT. DXA-VAT performed as well as a clinical read of VAT from a CT scan and better than anthropomorphic and demographic models.

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. All the participants were postmenopausal, between the ages of 50 and 79 years, at the time of recruitment and were followed for up to 9 years. Bone density and hip geometry were assessed using dual-energy X-ray absorptiometry. African admixture was measured for African Americans using genetic ancestry informative markers. Multiple regression and mixed-effects models were used for cross-sectional and longitudinal analyses, respectively. Covariates assessed from questionnaires and physical measurements were included in the analysis to control for possible confounding effects. The study results show significant correlations between percent of African admixture and HSA assessments. In comparison with non-Hispanic white women, significantly greater bone strength, as indicated by higher hip bone mineral density and stronger hip geometry, in women with higher African admixture was observed. However, women with higher percent African admixture had larger reductions in bone strength than non-Hispanic white women during the follow-up.