Identification of osteopenic women at high risk of fracture: the OFELY study

Ketogenic diet compromises vertebral microstructure and biomechanical characteristics in mice

Ketogenic diet (KD) compromised the microstructure of cancellous bone and the mechanical property in the appendicular bone of mice, while the effects of KD on the axial bone have not been reported. This study aimed to compare the changes in the microstructure and mechanical properties of the forth lumbar (L4) vertebra in KD and ovariectomized (OVX) mice. Forty eight-week-old female C57BL/6J mice were assigned into four groups: SD (standard diet) + Sham, SD + OVX, KD + Sham, and KD + OVX groups. L4 vertebra was scanned by micro-CT to examine the microstructure of cancellous bone, after which simulative compression tests were performed using finite element (FE) analysis. Vertebral compressive test and histological staining of the L4 and L5 vertebrae were performed to observe the biomechanical and histomorphologic changes. The KD + Sham and SD + OVX exhibited a remarkable declination in the parameters of cancellous bone compared with the SD + Sham group, while KD + OVX demonstrated the most serious bone loss in the four groups. The stiffness was significantly higher in the SD + Sham group than the other three groups, but no difference was found between the remaining groups. The trabecular parameters were significantly correlated with the stiffness. Meanwhile, the OVX + Sham and KD + OVX groups showed a significant decrease in the failure load of compressive test, while there was no difference between the KD + Sham and SD + Sham groups. These findings suggest that KD may compromise the vertebral microstructure and compressive stiffness to a similar level as OVX did, indicating adverse effects of KD on the axial bone of the mice.

Algorithm for the Use of Biochemical Markers of Bone Turnover in the Diagnosis, Assessment and Follow-Up of Treatment for Osteoporosis

Introduction

Increased biochemical bone turnover markers (BTMs) measured in serum are associated with bone loss, increased fracture risk and poor treatment adherence, but their role in clinical practice is presently unclear. The aim of this consensus group report is to provide guidance to clinicians on how to use BTMs in patient evaluation in postmenopausal osteoporosis, in fracture risk prediction and in the monitoring of treatment efficacy and adherence to osteoporosis medication.

Methods

A working group with clinical scientists and osteoporosis specialists was invited by the Scientific Advisory Board of European Society on Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO).

Results

Serum bone formation marker PINP and resorption marker βCTX-I are the preferred markers for evaluating bone turnover in the clinical setting due to their specificity to bone, performance in clinical studies, wide use and relatively low analytical variability. BTMs cannot be used to diagnose osteoporosis because of low sensitivity and specificity, but can be of value in patient evaluation where high values may indicate the need to investigate some causes of secondary osteoporosis. Assessing serum levels of βCTX-I and PINP can improve fracture prediction slightly, with a gradient of risk of about 1.2 per SD increase in the bone marker in addition to clinical risk factors and bone mineral density. For an individual patient, BTMs are not useful in projecting bone loss or treatment efficacy, but it is recommended that serum PINP and βCTX-I be used to monitor adherence to oral bisphosphonate treatment. Suppression of the BTMs greater than the least significant change or to levels in the lower half of the reference interval in young and healthy premenopausal women is closely related to treatment adherence.

Conclusion

In conclusion, the currently available evidence indicates that the principal clinical utility of BTMs is for monitoring oral bisphosphonate therapy.

Biochemical markers of bone turnover and risk of incident hip fracture in older women: the Cardiovascular Health Study

The relationships of osteocalcin (OC) and C-telopeptide of type I collagen (CTX) with long-term incidence of hip fracture were examined in 1680 post-menopausal women from a population-based study. CTX, but not OC, levels were associated with incident hip fracture in these participants, a relationship characterized by an inverted U-shape.

INTRODUCTION

We sought to investigate the relationships of OC, a marker of bone formation, and CTX, a marker of bone resorption, with long-term incidence of hip fracture in older women.

METHODS

We included 1680 women from the population-based Cardiovascular Health Study (mean [SD] age 74.5 [5.0] years). The longitudinal association of both markers with incidence of hip fracture was examined using multivariable Cox models.

RESULTS

During a median follow-up of 12.3 years, 288 incident hip fractures occurred. Linear spline analysis did not demonstrate an association between OC levels and incident hip fracture. By contrast, increasing levels of CTX up to the middle-upper range were associated with a significantly greater risk of hip fracture (HR = 1.52 per SD increment, 95% CI = 1.10-2.09), while further increases were associated with a marginally non-significant lower risk (HR = 0.80 per SD increment, 95% CI = 0.63-1.01), after full adjustment for potential confounders. In analyses of quartiles, CTX exhibited a similar inverted U-shaped relationship with incident fracture after adjustment, with a significant association observed only for the comparison of quartile 3 to quartile 1 (HR = 1.63, 95% CI = 1.10-2.43). In a subset with available measures, both OC and CTX were inversely associated with bone mineral density of the hip.

CONCLUSION

CTX, but not OC, levels were associated with incident hip fracture in post-menopausal women, a relationship characterized by an inverted U-shape. These findings highlight the complex relationship of bone turnover markers with hip fracture risk.

Performance of fracture risk assessment tool in HIV-positive male individuals aged ≥45 years on suppressive antiretroviral therapy

INTRODUCTION

An age-specific evaluation and management algorithm for reduced bone mineral density (BMD) is suggested for HIV-positive patients without major risk factors. Whether combination of BMD and the Fracture Risk Assessment Tool (FRAX) may detect more individuals for therapeutic interventions remains unclear. We aimed to determine the prevalence of middle-aged or older HIV-positive males fitting the criteria of therapeutic interventions with different approaches.

METHODS

From July 2016 to February 2018, HIV-positive male patients aged ≥45 years receiving suppressive antiretroviral therapy were recruited in a cross-sectional study, at two designated hospitals for HIV care in northern Taiwan. Patients with malignancy, AIDS, pre-existing bone disease or immobilization were excluded. Information on clinical and demographic characteristics, FRAX questionnaire, activity questionnaire, BMD and serum 25(OH)D was obtained. FRAX scores combined with BMD (FRAX/BMD) and without BMD (FRAX) were calculated. The data were analysed on the basis of major risk factors for fragility fracture and age stratification, FRAX score and BMD results respectively.

RESULTS

We enrolled 330 patients with a mean age of 51.6 years and CD4 610 cells/μL, in whom 98.1% (n = 324) underwent BMD assessment of one site or more. By FRAX, 6.7% (n = 22) reached treatment thresholds (10-year risk of major osteoporotic fracture ≥20% and/or hip fracture ≥3%). The prevalence of osteopenia (-2.5

CONCLUSIONS

With FRAX as a screening approach among HIV-positive male patients aged ≥45 years, addition of BMD assessment may detect more candidates for therapeutic management.

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Key Words

• ageing
• bone mineral density
• combination antiretroviral therapy
• osteopenia
• osteoporosis

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MESH Headings

• Adult
• Algorithms
• Anti-HIV Agents/therapeutic use
• Bone Density
• Cross-Sectional Studies
• Fractures, Bone/etiology
• HIV Seropositivity/complications
• HIV Seropositivity/drug therapy
• HIV Seropositivity/epidemiology
• Hip Fractures/etiology
• Humans
• Male
• Middle Aged
• Osteoporosis/etiology
• Osteoporotic Fractures/etiology
• Prevalence
• Risk Factors
• Surveys and Questionnaires
• Taiwan/epidemiology

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Affiliation(s)

Mao‐Song Tsai Department of Internal MedicineFar Eastern Memorial HospitalNew Taipei CityTaiwan School of MedicineCollege of MedicineFu Jen Catholic UniversityNew Taipei CityTaiwan
Jun‐Yu Zhang Center of Infection ControlNational Taiwan University HospitalTaipeiTaiwan
Hsin‐Yun Sun Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan
Wen‐Chun Liu Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan
Pei‐Ying Wu Center of Infection ControlNational Taiwan University HospitalTaipeiTaiwan
Chia‐Jui Yang Department of Internal MedicineFar Eastern Memorial HospitalNew Taipei CityTaiwan School of MedicineNational Yang‐Ming UniversityTaipeiTaiwan
Chien‐Ching Hung Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan Department of Tropical Medicine and ParasitologyNational Taiwan University College of MedicineTaipeiTaiwan

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Collaborators Collapse

Lack of Association Between Select Circulating miRNAs and Bone Mass, Turnover, and Fractures: Data From the OFELY Cohort

Postmenopausal osteoporosis is characterized by the occurrence of fragility fracture with an increase in morbidity and mortality. Recently, microRNAs (miRNAs) have raised interest as regulators of translational repression, mediating a number of key processes, including bone tissue in both physiological and diseased states. The aim of this study was to examine the serum levels of 32 preselected miRNAs with reported function in bone and their association with osteoporotic fracture. We performed cross-sectional and longitudinal analyses from the OFELY Cohort. Serum levels of the miRNAs were quantified by qRT-PCR in 682 women: 99 premenopausal and 583 postmenopausal women, with 1 and 122 women with prevalent fragility fractures in each group, respectively. We have collected clinical variables (such as age, prevalent, and incident fractures), bone turnover markers (BTMs), BMD by dual X-ray absorptiometry, and bone microarchitecture with HRpQCT. We observed a number of miRNAs to be associated with fragility fractures (prevalent or incident), BTMs, BMD, and microarchitecture. This effect, however, was negated after age adjustment. This may be because age was also strongly associated with the serum levels of the 32 miRNAs (correlation coefficient up to 0.49), confirming previous findings. In conclusion, in a well-characterized prospective cohort with a sizeable sample size, we found no evidence that these 32 preselected miRNAs were not associated with BTMs, BMD, microarchitecture, and or fragility fractures. © 2019 American Society for Bone and Mineral Research.

Cost-benefit analysis of calcium and vitamin D supplements

If all adults with osteoporosis in the European Union (EU) and United States (US) used calcium and vitamin D supplements, it could prevent more than 500,000 fractures/year in the EU and more than 300,000/year in the US and save approximately €5.7 billion and US $3.3 billion annually.

PURPOSE

Evaluate the cost-effectiveness of calcium/vitamin D supplementation for preventing osteoporotic fractures.

METHODS

A cost-benefit analysis tool was used to estimate the net cost savings from reduced fracture-related hospital expenses if adults with osteoporosis in the EU and US used calcium/vitamin D supplements. A 14% relative risk reduction of fracture with calcium/vitamin D supplementation from a recent systematic review and meta-analysis of randomized, controlled trials was used as the basis for the benefit estimate. Other model inputs were informed by epidemiologic, clinical, and cost data (2016-2017) obtained via the medical literature or public databases. Analyses estimated the total number of avoided fractures and associated cost savings with supplement use. Net cost benefit was calculated by subtracting the supplements' market costs from those savings.

RESULTS

The > 30 million persons in the EU and nearly 11 million in US with osteoporosis experience about 3.9 million and 2.3 million fractures/year and have annual hospital costs exceeding €50 billion and $28 billion. If all persons with osteoporosis used calcium and vitamin D supplements, there would be an estimated 544,687 fewer fractures/year in the EU and 323,566 fewer in the US, saving over €6.9 billion and $3.9 billion; the net cost benefit would be €5,710,277,330 and $3,312,236,252, respectively.

CONCLUSIONS

Calcium and vitamin D supplements are highly cost-effective, and expanded use could considerably reduce fractures and related costs. Although these analyses included individuals aged ≥ 50 years, the observed effects are likely driven by benefits observed in those aged ≥ 65 years.

Coupling factors involved in preserving bone balance

Coupling during bone remodeling refers to the spatial and temporal coordination of bone resorption with bone formation. Studies have assessed the subtle interactions between osteoclasts and osteoblasts to preserve bone balance. Traditionally, coupling research related to osteoclast function has focused on bone resorption activity causing the release of growth factors embedded in the bone matrix. However, considerable evidence from in vitro, animal, and human studies indicates the importance of the osteoclasts themselves in coupling phenomena, and many osteoclast-derived coupling factors have been identified. These include sphingosine-1-phosphate, vesicular-receptor activator of nuclear factor-κB, collagen triple helix repeat containing 1, and cardiotrophin-1. Interestingly, neuronal guidance molecules, such as slit guidance ligand 3, semaphorin (SEMA) 3A, SEMA4D, and netrin-1, originally identified as instructive cues allowing the navigation of growing axons to their targets, have been shown to be involved in the intercellular cross-talk among bone cells. This review discusses osteoclast-osteoblast coupling signals, including recent advances and the potential roles of these signals as therapeutic targets for osteoporosis and as biomarkers predicting human bone health.

Automated quantitative morphometry of vertebral heights on spinal radiographs: comparison of a clinical workflow tool with standard 6-point morphometry

A workflow tool for measurements of vertebral heights on lateral spine radiographs based on automated placements of 6 points per vertebra was evaluated. The tool helps to standardize point placement among operators. Its success rate is very good in normal vertebrae but lower in vertebrae with more severe fractures. Manual corrections were required in 192 of 1257 analyzed vertebrae.

INTRODUCTION

To evaluate a new workflow tool (SA) for the automated measurements of vertebral heights on lateral spine radiographs.

METHODOLOGY

Lateral radiographs from 200 postmenopausal women were evaluated at two visits. Genant's semi-quantitative fracture assessment (SQ) and manual quantitative morphometry (QM) results were available from prior analyses. Vertebral heights from point placements using SA were compared with manual 6-point placement QM. Differences were quantified as RMS coefficient of variations (rmsCV) and standard deviations (rmsSD).

RESULTS AND CONCLUSIONS

SA required manual corrections in 192 of 1257 vertebrae. SA heights were larger than QM ones by 2.2-3.6%. Correlations (r² > 0.92) between SA and QM were very high. Differences between QM and SA were higher for fractured (SQ = 2; rmsCV% 14.5%) than for unfractured vertebrae (rmsCV% 4.2-4.7%). rmsCV% for QM varied between 3 and 6% and for SA between 2.5 and 7.5%. For SA, highest rmsCV% was obtained for T4 and L4. Manual correction mostly affected the end vertebrae T4 and L4. SA helps to standardize point placement among operators. The algorithm success rate is very good in normal vertebrae but lower in vertebrae with more severe fractures, which are of greater clinical interest but are more readily recognized without morphometric measurements.

Assessment and hormonal management of osteoporosis

Postmenopausal osteoporosis is a frequent health issue in women. Because osteoporosis-related fractures cause a significant increase in mortality and morbidity, it is clinically important to identify as soon as possible women at increased risk for future fracture so that preventive measures can be instituted. At the beginning of menopause, evaluation of the subsequent risk of fracture is not so easy. Most screening tools fail to accurately identify those women who will fracture within the next 10 years. A history of a prior fracture and low bone mineral density are the only major consistently found predictors for the risk of fracture. On the other hand, it is no longer a question whether menopause hormone therapy is efficient not only to prevent postmenopausal bone loss but also the incidence of fragility fracture. Over the last years, utility of menopause hormone therapy for the prevention of osteoporosis has been questioned due to safety concerns. In light of the most recent reports on a more favorable benefit/risk balance than was initially claimed in early postmenopausal women, this needs to be reconsidered. Prevention of bone loss in those women with a moderate or slightly high risk of fracture is likely a strategy to reduce fracture risk in older women. Menopause hormone therapy must be considered as a true primary preventive therapy more than an anti-fracture therapy at an age when the risk of fracture is likely much lower than later in life. Only thereafter should other anti-osteoporotic medications be discussed in women still at high risk for fracture.

Gonadal Hormones in the Pathogenesis and Treatment of Bone Health in Patients with Chronic Kidney Disease: a Systematic Review and Meta-Analysis

PURPOSE OF REVIEW

Patients with chronic kidney disease (CKD) have a greatly increased fracture risk compared with the general population. Gonadal hormones have an important influence on bone mineral density (BMD) and fracture risk, and hormone therapies can significantly improve these outcomes. Gonadal dysfunction is a frequent finding in patients with CKD; yet, little is known about the impact of gonadal hormones in the pathogenesis and treatment of bone health in patients with CKD. This systematic review and meta-analysis aimed to examine the effects of gonadal hormones and hormone therapies on bone outcomes in men and women with CKD.

METHODS

EMBASE, MEDLINE, SCOPUS, and clinical trial registries were systematically searched from inception to February 14, 2018 for studies that assessed gonadal hormones or hormone treatments with bone outcomes in patients with CKD stage 3-5D. Two independent reviewers screened the titles and abstracts of search results according to inclusion criteria and assessed study quality and risk of bias using validated assessment tools.

RECENT FINDINGS

Thirteen studies met the inclusion criteria. Six moderate-to-high quality observational studies showed inconsistent association between any gonadal hormone and bone outcomes, limited by significant study heterogeneity. Five moderate-high risk of bias interventional studies examined treatment with selective oestrogen receptor modulators in post-menopausal women (four using raloxifene and one bazedoxifene) and demonstrated variable effects on BMD and fracture outcomes. Meta-analysis of raloxifene treatment in post-menopausal women demonstrated improvement in lumbar spine (SMD 3.30; 95% CI 3.21-3.38) and femoral neck (SMD 3.29; 95% CI 3.21-3.36) BMD compared with placebo. Transdermal oestradiol/norethisterone in pre-menopausal women receiving dialysis (n = 1 study), demonstrated BMD improvement over 12 months. Testosterone treatment for 6 months in dialysis-dependant men (n = 1 study) did not improve BMD. There is evidence that raloxifene treatment may be beneficial in improving BMD in post-menopausal women with CKD. There is insufficient evidence for other hormone treatments in men or women. Despite high fracture rates and frequent gonadal dysfunction in patients with CKD, significant evidence gaps exist, and well-designed studies are required to specifically assess the impact of gonadal status in the pathogenesis of CKD-related bone fragility and its treatment.

Identification of novel variants associated with osteoporosis, type 2 diabetes and potentially pleiotropic loci using pleiotropic cFDR method

AIMS

Clinical and epidemiological findings point to an association between type 2 diabetes (T2D) and osteoporosis. Genome-wide association studies (GWASs) have been fruitful in identifying some loci potentially associated with osteoporosis and T2D respectively. However, the total genetic variance for each of these two diseases and the shared genetic determination between them are largely unknown. The aim of this study was to identify novel genetic variants for osteoporosis and/or T2D.

METHODS

First, using a pleiotropic conditional false discovery rate (cFDR) method, we analyzed two GWAS summary data of femoral neck bone mineral density (FN_BMD, n = 53,236) and T2D (n = 159,208) to identify novel shared genetic loci. FN_BMD is an important risk factor for osteoporosis. Next, to explore the potential functions of the identified potential pleiotropic genes, differential expression analysis was performed for them in monocytes and peripheral blood mononuclear cells (PBMCs) as these cells are relevant to the etiology of osteoporosis and/or T2D. Further, weighted gene co-expression analysis (WGCNA) was conducted to identify functional connections between novel pleiotropic genes and known osteoporosis/T2D susceptibility genes by using transcriptomic expression datasets in bone biopsies (E-MEXP-1618) and pancreatic islets (GSE50397). Finally, multi-trait fine mapping for the detected pleiotropic risk loci were conducted to identify the SNPs that have the highest probability of being causal for both FN_BMD and T2D.

RESULTS

We identified 27 significant SNPs with cFDR<0.05 for FN_BMD and 61 SNPs for T2D respectively. Four loci, rs7068487 (PLEKHA1), rs10885421 (TCF7L2), rs944082 (GNG12-AS1 (WLS)) and rs2065929 (PIFO||PGCP1), were found to be potentially pleiotropic and shared between FN_BMD and T2D (ccFDR<0.05). PLEKHA1 was found differentially expressed in circulating monocytes between high and low BMD subjects, and PBMCs between diabetic and non-diabetic conditions. WGCNA showed that PLEKHA1 and TCF7L2 were interconnected with multiple osteoporosis and T2D associated genes in bone biopsy and pancreatic islets, such as JAG, EN1 and CPE. Fine mapping showed that rs11200594 was a potentially causal variant in the locus of PLEKHA1. rs11200594 is also an eQTL of PLEKHA1 in multiple tissue (e.g. peripheral blood cells, adipose and ovary) and is in strong LD with a number of functional variants.

CONCLUSIONS

Four potential pleiotropic loci were identified for shared genetic determination of osteoporosis and T2D. Our study highlights PLEKHA1 as an important potentially pleiotropic gene. The findings may help us gain a better understanding of the shared genetic determination between these two important disorders.

Low Osteogenic Yield in Human Pluripotent Stem Cells Associates with Differential Neural Crest Promoter Methylation

Human pluripotent stem cell-derived osteoblasts possess great potential for use in bone disorder elucidation and repair; however, while the general ability of human pluripotent stem cells to differentiate into osteoblasts and lay down bone-specific matrix has been shown, previous studies lack the complete characterization of the process whereby such osteoblasts are derived as well as a comparison between the osteogenic efficiency of multiple cell lines. Here, we compared the osteogenic potential of two human induced pluripotent stem cell lines (RIV9 and RIV4) to human H9 embryonic stem cells. Generally capable of osteogenic differentiation, the overall osteogenic yield was lower in the RIV9 and RIV4 lines and correlated with differential expression of osteocalcin (OCN) in mature cultures and PAX7 and TWIST1 during early differentiation. In the undifferentiated cells, the promoters of the latter two genes were differentially methylated potentially explaining the variation in differentiation efficiency. Furthermore, the expression signatures of selected neural crest and mesodermal genes and proteins suggested that H9 cells preferentially gave rise to neural crest-derived osteoblasts, whereas the osteoblasts in the RIV9 cultures were generated both through a mesodermal and a neural crest route although each at a lower rate. These data suggest that epigenetic dissimilarities between multiple PSC lines may lead to differences in lineage derivation and mineralization. Since osteoblast progenitors from one origin inadequately repair a defect in the other, these data underscore the importance of screening human pluripotent stem cells lines for the identity of the osteoprogenitors they lay down. Stem Cells 2018;36:349-362.

Cortical bone quality affectations and their strength impact analysis using holographic interferometry

It is now accepted that bone strength is a complex property determined mainly by three factors: quantity, quality and turnover of the bone itself. Most of the patients who experience fractures due to fragility could never develop affectations related to bone mass density (i.e. osteoporosis). In this work, the effect of secondary bone strength affectations are analyzed by simulating the degradation of one or more principal components (organic and inorganic) while they are inspected with a nondestructive optical technique. From the results obtained, a strong correlation among the hydroxyapatite, collagen and water is found that determines the bone strength.

Dysmobility syndrome is associated with prevalent morphometric vertebral fracture in older adults: the Korean Urban-Rural Elderly (KURE) study

In a community-dwelling elderly cohort, dysmobility syndrome was associated with elevated odds of morphometric vertebral fracture or any prevalent fracture, independent of age and covariates. Dysmobility syndrome improved discrimination for fracture when added to the FRAX score.

INTRODUCTION

Dysmobility syndrome was coined to indicate patients with impaired musculoskeletal health. Data on the association of dysmobility syndrome with prevalent morphometric vertebral fracture (VF) in elderly persons are limited.

METHODS

A total of 1369 community-dwelling elderly subjects (mean age 71.6 years; women 66%) were analyzed. Dysmobility syndrome was defined as ≥ 3 components among falls, low lean mass, high fat mass, osteoporosis, low grip strength, and low timed get-up-and-go performance. VF was defined as a ≥ 25% reduction in the height of vertebral bodies in plain radiographs. Modified cutpoints of each component at which elevate the odds of fracture were investigated using receiver-operating characteristics analysis. Net reclassification improvement (NRI) and integrated discrimination index (IDI) were calculated to assess additive discriminatory value of dysmobility syndrome over FRAX.

RESULTS

The prevalence of VF and any fracture composite of VF and non-VF was 16% and 25%, respectively, increasing according to number of dysmobility components (from 0 to 5; VF 10-35%; any fracture 16-45%). Dysmobility syndrome was associated with elevated odds of VF (adjusted OR [aOR] 1.52, 95% CI 1.08-2.15) or any fracture (aOR 1.46, 95% CI 1.07-1.98) but no longer with non-VF (aOR 1.31, 95% CI 0.86-1.98) in multivariate model, whereas modified definition showed robust association with non-VF (aOR 1.79, 95% CI 1.23-2.60). Dysmobility syndrome improved discrimination for prevalent fracture when added to FRAX (NRI 0.25, 95% CI 0.13-0.37; IDI 0.020, 95% CI 0.014-0.026).

CONCLUSIONS

Dysmobility syndrome was associated with elevated odds of morphometric VF in community-dwelling older adults, independent of age and covariates.

HIV Infection Is Associated With Abnormal Bone Microarchitecture: Measurement of Trabecular Bone Score in the Women's Interagency HIV Study

OBJECTIVES

We compared skeletal microarchitecture using trabecular bone score (TBS) and evaluated relationships between change in TBS and lumbar spine (LS) bone mineral density (BMD) in women with and without HIV.

METHODS

Dual-energy X-ray absorptiometry was performed on 319 women with HIV and 118 without HIV in the Women's Interagency HIV Study at baseline and 2 and 5 years, to measure regional BMD and lean and fat mass. TBS was extracted from LS dual-energy X-ray absorptiometry images and examined continuously and categorically [normal (≥1.35), intermediate (1.20-1.35), or degraded (≤1.20) microarchitecture]. Pearson correlation and linear regression examined associations of TBS with regional BMD at baseline and over time.

RESULTS

Women with HIV were older (43 vs. 37 years), more likely to be postmenopausal (27% vs. 4%), have lower baseline total fat mass, trunk fat, and leg fat than uninfected women, degraded microarchitecture (27% vs. 9%, P = 0.001), and lower baseline mean TBS (1.3 ± 0.1 vs. 1.4 ± 0.1, P < 0.001). After adjusting for age, race, menopause status, and body mass index, TBS remained lower in women with HIV (P < 0.0001). Annual change in TBS correlated with LS BMD change among women with HIV (r = 0.36, P < 0.0001) and without HIV (r = 0.26, P = 0.02); however, mean % annual TBS change did not differ by HIV status (-1.0%/yr ± 2.9% for HIV+ vs. -0.8%/yr ± 1.7% for HIV-, P = 0.42).

CONCLUSIONS

Women with HIV have worse bone microarchitecture than uninfected women, but annual percent change in LS BMD or TBS was similar. Use of TBS as an adjunct to BMD to improve prediction of fragility fractures in women with HIV merits further study.

Bone Turnover Markers Are Not Associated With Hip Fracture Risk: A Case-Control Study in the Women's Health Initiative

Current guidelines recommend that serum C-terminal telopeptide of type I collagen (CTX) and serum procollagen type 1 aminoterminal propeptide (PINP), measured by standardized assays, be used as reference markers in observational and interventional studies. However, there are limited data to determine whether serum CTX and PINP are associated with hip fracture risk among postmenopausal women. We determined the associations of serum CTX and serum PINP with hip fracture risk among postmenopausal women aged 50 to 79 years at baseline. We performed a prospective case-control study (400 cases, 400 controls) nested in the Women's Health Initiative Observational Study, which enrolled participants at 40 US clinical centers. Cases were women with incident hip fracture not taking osteoporosis medication; hip fractures were confirmed using medical records. Untreated controls were matched by age, race/ethnicity, and date of blood sampling. Serum CTX and serum PINP were analyzed on 12-hour fasting blood samples. The main outcome measure was incident hip fracture risk (mean follow-up 7.13 years). After adjustment for body mass index, smoking, frequency of falls, history of fracture, calcium and vitamin D intake, and other relevant covariates, neither serum CTX level nor serum PINP level was statistically significantly associated with hip fracture risk (CTX p_trend  = 0.22, PINP p_trend  = 0.53). Our results do not support the utility of serum CTX level or PINP level to predict hip fracture risk in women in this age group. These results will inform future guidelines regarding the potential utility of these markers in fracture prediction. © 2018 American Society for Bone and Mineral Research.

Comparative assessment of fracture risk among osteoporosis and osteopenia patients: a cross-sectional study

BACKGROUND

Both osteoporosis and osteopenia remain worldwide public health concerns. They both lead to bone fractures, which can lead to disability and burden on those who are afflicted.

OBJECTIVES

To assess and compare fracture risk between these two groups of patients.

PATIENTS AND METHODS

Our cross-sectional study included 82 patients (46 with osteoporosis and 36 with osteopenia) with an average age of 63±9.33 years, who received treatment at the Clinic for Medical Rehabilitation, Clinical Center of Vojvodina in Novi Sad, Serbia. The assessment of the fracture risk was executed by applying the Fracture Assessment Risk (FRAX) index (an algorithm developed by the World Health Organization) based on clinical fracture risks or combination of clinical fracture risks and bone mineral density.

RESULTS

Patients with osteoporosis had significantly higher risk of major fracture compared to patients with osteopenia (p<0.01). Results from FRAX index in osteoporotic patients showed that more than half (58.70%) of patients had a low risk of fracture; less than one-third of patients (30.43%) had an intermediate risk of major osteoporotic fracture, while almost four out of every 10 (39.96%) had a high risk of hip fracture. The majority of patients with osteopenia (63.89%) had a low risk of major osteoporotic fracture, while 36.11% of them had an intermediate risk. The majority of patients with osteopenia (91.67%) had a low risk of hip fracture. Statistically significant differences in relation to specific fracture risks between patients with osteoporosis and osteopenia, in particular, weight (t=-2.250, p=0.027*) and previous fractures (t=2.985, p=0.004**), were established.

CONCLUSION

Osteoporosis patients had a high risk of major osteoporotic fracture, while there was no association between the intermediate level for major osteoporotic fracture and osteo-penia. For patients suffering from an increased fracture risk, especially those who had already been diagnosed with osteoporosis, preventive measures such as designing individual therapeutic programs should be adopted.

The challenges of diagnosing osteoporosis and the limitations of currently available tools

Dual-energy X-ray absorptiometry (DXA) was the first imaging tool widely utilized by clinicians to assess fracture risk, especially in postmenopausal women. The development of DXA nearly coincided with the availability of effective osteoporosis medications. Although osteoporosis in adults is diagnosed based on a T-score equal to or below − 2.5 SD, most individuals who sustain fragility fractures are above this arbitrary cutoff. This incongruity poses a challenge to clinicians to identify patients who may benefit from osteoporosis treatments. DXA scanners generate 2 dimensional images of complex 3 dimensional structures, and report bone density as the quotient of the bone mineral content divided by the bone area. An obvious pitfall of this method is that a larger bone will convey superior strength, but may in fact have the same bone density as a smaller bone. Other imaging modalities are available such as peripheral quantitative CT, but are largely research tools. Current osteoporosis medications increase bone density and reduce fracture risk but the mechanisms of these actions vary. Anti-resorptive medications (bisphosphonates and denosumab) primarily increase endocortical bone by bolstering mineralization of endosteal resorption pits and thereby increase cortical thickness and reduce cortical porosity. Anabolic medications (teriparatide and abaloparatide) increase the periosteal and endosteal perimeters without large changes in cortical thickness resulting in a larger more structurally sound bone. Because of the differences in the mechanisms of the various drugs, there are likely benefits of selecting a treatment based on a patient’s unique bone structure and pattern of bone loss. This review retreats to basic principles in order to advance clinical management of fragility fractures by examining how skeletal biomechanics, size, shape, and ultra-structural properties are the ultimate predictors of bone strength. Accurate measurement of these skeletal parameters through the development of better imaging scanners is critical to advancing fracture risk assessment and informing clinicians on the best treatment strategy. With this information, a “treat to target” approach could be employed to tailor current and future therapies to each patient’s unique skeletal characteristics.

2018 update of French recommendations on the management of postmenopausal osteoporosis

OBJECTIVES

To update the 2012 recommendations on pharmacotherapy for postmenopausal osteoporosis, under the aegis of the Bone Task Force of the French Society for Rheumatology (SFR) and of the Osteoporosis Research and Information Group (GRIO), in collaboration with scientific societies (Collège national des généralistes enseignants, Collège national des gynécologues et obstétriciens français, Fédération nationale des collèges de gynécologie médicale, Groupe d'étude de la ménopause et du vieillissement hormonal, Société française de chirurgie orthopédique, Société française d'endocrinologie, and Société française de gériatrie et de gérontologie).

METHODS

Updated recommendations were developed by a task force whose members represented the medical specialties involved in the management of postmenopausal osteoporosis. The update was based on a literature review and developed using the method advocated by the French National Authority for Health (HAS).

DISCUSSION AND CONCLUSION

The updated recommendations place strong emphasis on the treatment of women with severe fractures, in whom the use of osteoporosis medications is recommended. All the available osteoporosis medications are suitable in patients with severe fractures; zoledronic acid deserves preference as the fist-line drug after a hip fracture. In patients with or without non-severe fractures, the decision to use osteoporosis medications is based on bone mineral density values and in challenging cases, on probabilities supplied by prediction tools such as FRAX^®. All osteoporosis medications are suitable; raloxifene should be reserved for patients at low risk for peripheral fractures. The fracture risk should be reevaluated every 2 to 3 years to decide on the best follow-up treatment. These updated recommendations discuss the selection of first-line osteoporosis medications and treatment sequences.

Automation of a DXA-based finite element tool for clinical assessment of hip fracture risk

Finite element analysis of medical images is a promising tool for assessing hip fracture risk. Although a number of finite element models have been developed for this purpose, none of them have been routinely used in clinic. The main reason is that the computer programs that implement the finite element models have not been completely automated, and heavy training is required before clinicians can effectively use them. By using information embedded in clinical dual energy X-ray absorptiometry (DXA), we completely automated a DXA-based finite element (FE) model that we previously developed for predicting hip fracture risk. The automated FE tool can be run as a standalone computer program with the subject's raw hip DXA image as input. The automated FE tool had greatly improved short-term precision compared with the semi-automated version. To validate the automated FE tool, a clinical cohort consisting of 100 prior hip fracture cases and 300 matched controls was obtained from a local community clinical center. Both the automated FE tool and femoral bone mineral density (BMD) were applied to discriminate the fracture cases from the controls. Femoral BMD is the gold standard reference recommended by the World Health Organization for screening osteoporosis and for assessing hip fracture risk. The accuracy was measured by the area under ROC curve (AUC) and odds ratio (OR). Compared with femoral BMD (AUC = 0.71, OR = 2.07), the automated FE tool had a considerably improved accuracy (AUC = 0.78, OR = 2.61 at the trochanter). This work made a large step toward applying our DXA-based FE model as a routine clinical tool for the assessment of hip fracture risk. Furthermore, the automated computer program can be embedded into a web-site as an internet application.

Evaluation of Radius Microstructure and Areal Bone Mineral Density Improves Fracture Prediction in Postmenopausal Women

A majority of low-trauma fractures occur in subjects with only moderate decrease of areal bone mineral density (aBMD), ie, osteopenia, assessed by dual-energy X-ray absorptiometry (DXA) or low fracture probability assessed by FRAX. We investigated whether peripheral bone microstructure and estimated strength improve the prediction of incident fractures beyond central DXA and FRAX. In this population-based study of 740 postmenopausal women (aged 65.0 ± 1.4 years) from the Geneva Retirees Cohort (ISRCTN registry 11865958), we assessed at baseline cortical (Ct) and trabecular (Tb) volumetric bone mineral density (vBMD) and microstructure by peripheral quantitative computed tomography (HR-pQCT); bone strength by micro-finite element analysis; aBMD and trabecular bone score (TBS) by DXA; and FRAX fracture probability. Eighty-five low-trauma fractures occurred in 68 women over a follow-up of 5.0 ± 1.8 years. Tb and Ct vBMD and microstructure predicted incident fractures, independently of each other and of femoral neck (FN) aBMD and FRAX (with BMD ± TBS). However, the associations were markedly attenuated after adjustment for ultra-distal radius aBMD (same bone site). The best discrimination between women with and without fracture was obtained at the radius with total vBMD, the combination of a Tb with a Ct parameter, or with failure load, which improved the area under the curve (AUC) for major osteoporotic fracture when added to FN aBMD (0.760 versus 0.695, p = 0.022) or to FRAX-BMD (0.759 versus 0.714, p = 0.015). The replacement of failure load by ultra-distal aBMD did not significantly decrease the AUC (0.753, p = 0.747 and 0.750, p = 0.509, respectively). In conclusion, peripheral bone microstructure and strength improve the prediction of fractures beyond central DXA and FRAX but are partially captured in aBMD measured by DXA at the radius. Because HR-pQCT is not widely available for clinical purposes, assessment of ultra-distal radius aBMD by DXA may meanwhile improve fracture risk estimation. © 2017 American Society for Bone and Mineral Research.

The QUALYOR (QUalité Osseuse LYon Orléans) study: a new cohort for non invasive evaluation of bone quality in postmenopausal osteoporosis. Rationale and study design

The diagnostic performance of densitometry is inadequate. New techniques of non-invasive evaluation of bone quality may improve fracture risk prediction. Testing the value of these techniques is the goal of the QUALYOR cohort.

INTRODUCTION

The bone mineral density (BMD) of postmenopausal women who sustain osteoporotic fracture is generally above the World Health Organization definition for osteoporosis. Therefore, new approaches to improve the detection of women at high risk for fracture are warranted.

METHODS

We have designed and recruited a new cohort to assess the predictive value of several techniques to assess bone quality, including high-resolution peripheral quantitative computerized tomography (HRpQCT), hip QCT, calcaneus texture analysis, and biochemical markers. We have enrolled 1575 postmenopausal women, aged at least 50, with an areal BMD femoral neck or lumbar spine T-score between - 1.0 and - 3.0. Clinical risk factors for fracture have been collected along with serum and blood samples.

RESULTS

We describe the design of the QUALYOR study. Among these 1575 women, 80% were aged at least 60. The mean femoral neck T-score was - 1.6 and the mean lumbar spine T-score was -1.2. This cohort is currently being followed up.

CONCLUSIONS

QUALYOR will provide important information on the relationship between bone quality variables and fracture risk in women with moderately decreased BMD.

Comparisons of TBS and lumbar spine BMD in the associations with vertebral fractures according to the T-scores: A cross-sectional observation

Trabecular bone score (TBS) is a parameter of bone quality that has been shown to be related to vertebral fractures. This study aimed to analyze the difference in discriminatory power of TBS for vertebral fractures according to the bone mineral density (BMD) T-score. Areal BMD at the lumbar spine (LS, L1-L4), femur neck (FN) and total hip were assessed using dual x-ray absorptiometry (Discovery W, Hologic, Bedford, MA) in 929 women aged 50years or older. TBS was analyzed using iNsight software (Med-Imaps, Pessac, France). Vertebral fractures were identified on lateral X-ray films of the thoracic and lumbar spine using a semi-quantitative method. The study subjects consisted of 158 subjects (17.0%) with normal BMD, 461 (49.6%) with osteopenia and 310 (33.4%) with osteoporosis. The incident vertebral fractures were observed in 92 (9.9%) subjects, including 59 fractures in osteoporosis, 29 fractures in osteopenia, and only 4 fractures in normal BMD. We stratified study subjects into two groups according to their BMD T-scores, osteoporosis or osteopenia/normal BMD. The logistic regression model showed that LS BMD values per each 1 standard deviation (SD) decrease were significantly associated with increased risk of vertebral fracture in both osteoporosis and osteopenia/normal BMD group with stronger association in osteoporosis group. However, a TBS value that was lower by 1SD was significantly associated with vertebral fracture risk only in the osteopenia/normal BMD group. The TBS use in addition to FN BMD and age also showed significantly better discriminatory power for vertebral fracture only in the osteopenia/normal BMD group, but not osteoporosis group. In conclusion, TBS is significantly associated with vertebral fractures in subjects with osteopenia/normal BMD levels. Additional assessment of bone microarchitecture using TBS is better able to identify women at risk of fracture, in particular, those with relatively higher BMD.

Comparison between the gold standard DXA with calcaneal quantitative ultrasound based-strategy (QUS) to detect osteoporosis in an HIV infected cohort

INTRODUCTION

Osteoporosis represents one of the most frequent comorbidity among HIV patients. The current standard method for osteoporosis diagnosis is dual-energy X-ray absorptiometry. Calcaneal quantitative ultrasound can provide information about bone quality. The aims of this study are to compare these two methods and to evaluate their ability to screen for vertebral fracture.

METHODS

This cross-sectional study was conducted in HIV patients attending the Clinic of Infectious and Tropical Diseases of Brescia during 2014 and who underwent lumbar/femoral dual-energy X-ray absorptiometry, vertebral fracture assessment and calcaneal quantitative ultrasound. The assessment of osteoporosis diagnostic accuracy was performed for calcaneal quantitative ultrasound and for vertebral fracture comparing them with dual-energy X-ray absorptiometry.

RESULTS

We enrolled 73 patients and almost 48% of them had osteoporosis with at least one of the method used. Vertebral fracture were present in 27.4%. Among patients with normal bone measurements, we found vertebral fracture in proportion between 10% and 30%. If we used calcaneal quantitative ultrasound method and/or X-ray as screening, the percentages of possible savable dual-energy X-ray absorptiometry ranged from 12% to 89% and misclassification rates ranged from 0 to 24.6%. A combined strategy, calcaneal quantitative ultrasound and X-Ray, identified 67% of patients with low risk of osteoporosis, but 16.4% of patients were misclassified.

CONCLUSIONS

We observed that patients with osteoporosis determined by calcaneal quantitative ultrasound and/or dual-energy X-ray absorptiometry have higher probability to undergo vertebral fracture, but neither of them can be used for predicting vertebral fracture. Use of calcaneal quantitative ultrasound for screening is a reasonable alternative of dual-energy X-ray absorptiometry since our study confirm that none strategy is clearly superior, but both screen tools must be always completed with X-ray.

A highly sensitive electrochemical biosensor based on AuNP-modified gold electrodes for selective determination of serum levels of crosslaps

This article explains a step-wise protocol to develop an electrochemical sensor to quantify serum levels of C-telopeptide (CTX) crosslinks also known as crosslaps in a matter of minutes and with high level of accuracy. The technique needs only one-step (incubation) and can thus be used for point of care screening. Due to the excellent electrical properties of the as-prepared immunosensor, CTX levels were successfully measured from 1 to 1000 pg/mL. This is while the normal reference of the marker is 50-450 pg/mL, suggesting that the sensor can acceptably detect CTX. The results also showed a good correlation with ECLIA in measuring serum levels of CTX.

The use of bone mineral density measured by dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed microtomography in chronic kidney disease

Chronic kidney disease (CKD) is a risk factor for fractures. The current evaluation of fracture risk is based upon the combination of various clinical factors and quantitative imaging of bone. X-ray-based tools were developed to evaluate bone status and predict fracture risk. Dual energy X-ray absorptiometry (DXA) is available worldwide. Longitudinal studies showed that low areal Bone Mineral Density (BMD) measured by DXA predicts fractures in the CKD population as it does in non uremic populations, with good specificity and moderate sensitivity. Peripheral quantitative computed tomography (pQCT) and high resolution pQCT are research tools which measure volumetric BMD at the tibia and radius. They are able to discriminate between the cortical and trabecular envelopes which are differentially affected by renal osteodystrophy. In CKD, a rapid thinning and increased porosity at the cortex is observed which is associated with increased the risk for fracture.

Phenolics Isolated from Aframomum meleguta Enhance Proliferation and Ossification Markers in Bone Cells

Osteoporosis is a serious health problem characterized by decreased bone mineral density and deterioration of bone microarchitecture. Current antiosteoporotic agents exhibit a wide range of adverse effects; meanwhile, phytochemicals are effective and safer alternatives. In the current work, nine compounds belonging to hydroxyphenylalkane and diarylheptanoid groups were isolated from Aframomum meleguea seeds and identified as 6-gingerol (1), 6-paradol (2), 8-dehydrogingerdione (3), 8-gingerol (4), dihydro-6-paradol (5), dihydrogingerenone A (6), dihydrogingerenone C (7), 1,7-bis(3,4-dihydroxy-5-methoxyphenyl)heptane-3,5-diyl diacetate (8), and 1-(3,4-dihydroxy-5-methoxyphenyl)-7-(3,4-dihydroxyphenyl)heptane-3,5-diyl diacetate (9). The structures of isolated compounds were established by NMR and mass spectral data, in addition to referring to literature data. Exposure of MCF-7, MG-63, and SAOS-2 cells to subcytotoxic concentrations of the compounds under investigation resulted in accelerated proliferation. Among them, paradol was selected for further detailed biochemical analysis in SAOS-2 cells. DNA flowcytometric analysis of cell cycle distribution revealed that paradol did not induce any significant change in the proliferation index of SAOS-2 cells. Assessment of osteogenic gene expression revealed that paradol enhanced the expression of osteocyte and osteoblast-related genes and inhibited osteoclast and RUNX suppressor genes. Biochemically, paradol enhanced alkaline phosphatase activity and vitamin D content and decreased the osteoporotic marker acid phosphatase. In conclusion, paradol, which is a major constituents of A. melegueta seeds, exhibited potent proliferative and ossification characteristics in bone cells.

Quantitative two-dimensional ultrashort echo time magnetization transfer (2D UTE-MT) imaging of cortical bone

PURPOSE

To investigate quantitative 2D ultrashort echo time magnetization transfer (UTE-MT) imaging in ex vivo bovine cortical bone and in vivo human tibial cortical bone.

METHODS

Data were acquired from five fresh bovine cortical bone samples and five healthy volunteer tibial cortical bones using a 2D UTE-MT sequence on a clinical 3T scanner. The 2D UTE-MT sequence used four or five MT powers with five frequency offsets. Results were analyzed with a two-pool quantitative MT model, providing measurements of macromolecular fraction (f), macromolecular proton transverse relaxation times (T_2m ), proton exchange rates from water/macromolecular to the macromolecular/water pool (RM_0m /RM_0w ), and spin-lattice relaxation rate of water pool (R_1w ). A sequential air-drying study for a small bovine cortical bone chip was used to investigate whether above MT modeling parameters were sensitive to the water loss.

RESULTS

Mean fresh bovine cortical bone values for f, T_2m , R_1w , RM_0m , and RM_0w were 59.9 ± 7.3%, 14.6 ± 0.3 μs, 9.9 ± 2.4 s^-1 , 17.9 ± 3.6 s^-1 , and 11.8 ± 2.0 s^-1 , respectively. Mean in vivo human cortical bone values for f, T_2m , R_1w , RM_0m and RM_0w were 54.5 ± 4.9%, 15.4 ± 0.6 μs, 8.9 ± 1.1 s^-1 , 11.5 ± 3.5 s^-1 , and 9.5 ± 1.9 s^-1 , respectively. The sequential air-drying study shows that f, RM_0m , and R_1w were increased with longer drying time.

CONCLUSION

UTE-MT two-pool modeling provides novel and useful quantitative information for cortical bone. Magn Reson Med 79:1941-1949, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Adjusting FRAX® on TBS for identification of subjects at high risk of fractures

The objective of this study was to compare the proportion of patients at high fracture risk according to FRAX® and FRAX® adjusted on TBS in patients hospitalized for a non vertebral fractures. Patients were selected from a Fracture Liaison Service FLS): clinical risk factors, bone mineral density (BMD) and TBS were assessed at the time of the fracture. Without considering the current fracture, we calculated FRAX® and FRAX® adjusted on TBS (TBS-FRAX®), and compared the proportion of patients with a high risk for major osteoporotic fracture (MOF)>20% according to FRAX® and TBS-FRAX®, and the proportion of subjects who should be treated according to current guidelines. Four hundred and thirteen patients were included for a non vertebral fracture (84.5% women, mean age of 73.9±11.7years), Two hundred and eight patients (50.4%) had osteoporosis (T≤-2.5 at least one site) and the mean value of TBS was 1.206 (±0.111). The proportion of patients with a risk of MOF≥20% before the fracture was similar with FRAX® and TBS-FRAX® (24.7% vs 25.4%). The proportion of patients identified with a risk of MOF above the threshold value of therapeutic intervention was higher using TBS-FRAX® than FRAX® for the age categories of 60-70years (38.3% vs 30.9%, p=0.01) and 70-80years (31.2% vs. 26.6%, p=0.04). This study showed that the proportion of patients at high risk of fracture is similar using FRAX® and FRAX® adjusted on TBS in patients hospitalized for a non vertebral fracture in a FLS.

Bone Turnover Markers: Use in Fracture Prediction

Bone turnover markers (BTMs) provide us with a noninvasive approach to studying bone turnover and they can be measured easily and with good precision, especially using automated analyzers. BTMs increase at menopause, and these higher levels are associated with more rapid bone loss. In some but not all studies, they are also associated with greater risk of fracture. However, the evidence base for use as predictors of fracture is not robust, and so BTMs have not been included in fracture prediction models. Further research is needed, and this might include (1) use of reference analytes such as C-telopeptide of type I collagen and procollagen I N-propeptide, measured using automated analyzers in subjects in the fasting state on more than 1 occasion; (2) careful collection of vertebral fractures, which would be the primary endpoint; and (3) common approach to statistical analyses with results expressed as hazard ratio per standard deviation of increase in BTM. We believe that by improving our approach to studying the relationship between BTMs and fracture risk, any association will become clearer and that in the future we might then be able to include BTMs in our fracture prediction models.

Molecular Abnormalities Underlying Bone Fragility in Chronic Kidney Disease

Prevention of bone fractures is one goal of therapy for patients with chronic kidney disease-mineral and bone disorder (CKD-MBD), as indicated by the Kidney Disease: Improving Global Outcomes guidelines. CKD patients, including those on hemodialysis, are at higher risk for fractures and fracture-related death compared to people with normal kidney function. However, few clinicians focus on this issue as it is very difficult to estimate bone fragility. Additionally, uremia-related bone fragility has a more complicated pathological process compared to osteoporosis. There are many uremia-associated factors that contribute to bone fragility, including severe secondary hyperparathyroidism, skeletal resistance to parathyroid hormone, and bone mineralization disorders. Uremia also aggravates bone volume loss, disarranges microarchitecture, and increases the deterioration of material properties of bone through abnormal bone cells or excess oxidative stress. In this review, we outline the prevalence of fractures, the interaction of CKD-MBD with osteoporosis in CKD patients, and discuss possible factors that exacerbate the mechanical properties of bone.

Elevated Bone Turnover Markers Are Associated With Distal Radius Fractures in Premenopausal Women

PURPOSE

To examine whether premenopausal women with distal radius fractures (DRF) have lower levels of 25-hydroxyvitamin D (25[OH]D) and increased levels of serum bone turnover markers (BTM) compared with control subjects without fracture.

METHODS

Premenopausal women with DRF (n = 20) were prospectively enrolled and compared with age-matched individuals without a fracture (n = 20). Outcome measures included serum levels of 25(OH)D, parathyroid hormone (PTH), markers of bone formation (osteocalcin [OC], N-terminal extension propeptide of type I collagen [P1NP], and bone-specific alkaline phosphatase [BSAP]), and markers of bone resorption (C-terminal telopeptide of type I collagen [CTX]). We assessed associations between BTM and DRF with conditional logistic regression and the utility of markers for fracture prediction with a receiver operator characteristic analysis.

RESULTS

The fracture group and control group were comparable in terms of age at menarche and BMI. Patients who had fractures had significantly greater levels of OC and P1NP, and demonstrated a nonsignificant increase in CTX. Levels of 25(OH)D, PTH, and BSAP were similar between groups. Conditional logistic regression revealed independent associations between DRF and increased levels of OC and CTX. Levels of 25(OH)D and PTH were not associated with DRF. Receiver operator characteristic analyses demonstrated moderate performance for OC, P1NP, BSAP, and CTX in predicting DRF.

CONCLUSIONS

Levels of 25(OH)D were not associated with DRF in premenopausal women. However, patients with DRF had increased levels of BTM of formation and resorption. Bone turnover markers may be helpful in predicting future fragility fractures in premenopausal women.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Novel imaging modalities for the comparison of bone microarchitecture among HIV+ patients with and without fractures: a pilot study

BACKGROUND

HIV-infected adults have increased fracture risk.

OBJECTIVES

To generate pilot data comparing bone density, structure, and strength between HIV-infected adults with and without a prior fracture.

METHODS

Adults with and without a prior fracture after their HIV diagnosis were matched 1:1 based on age, sex, race, and smoking history. Participants underwent dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS), hip structural analyses (HSA), vertebral fracture assessment (VFA), high-resolution peripheral quantitative tomography (HR-pQCT) and measurement of bone turnover markers. Results were compared between cases and controls, with differences expressed as percentages of control group values.

RESULTS

23 pairs were included. On DXA, cases had lower areal bone mineral density (aBMD) at the total hip (median difference in T-score -0.25, p = 0.04), but not the lumbar spine (median difference in T-score 0.10, p = 0.68). Cases had greater abnormalities in HSA and most HR-pQCT and HSA measures, by up to 15%. VFA revealed two subclinical fractures among cases but none among controls. TBS, CTX, and P1NP levels were similar between groups, with differences of 1.9% (p = 0.90), 9.7% (p = 0.55), and 10.0% (p = 0.24), respectively. For each parameter, we report the median and interquartile range for the absolute and relative difference between cases and controls, the correlation between cases and controls, and our recruitment rates, to inform the design of future studies.

CONCLUSIONS

These pilot data suggest potential differences in bone structure, estimated bone strength, and asymptomatic vertebral fractures among HIV-infected adults with and without fracture, warranting further study as markers of fracture risk in HIV.

Bone Turnover Markers in the Diagnosis and Monitoring of Metabolic Bone Disease

BACKGROUND

Disorders of bone metabolism, most notably osteoporosis, are highly prevalent and predispose to fractures, causing high patient morbidity and mortality. Diagnosis and monitoring of bone metabolic defects can present a major challenge as these disorders are largely asymptomatic and radiographic measures of bone mass respond slowly to changes in bone physiology.

CONTENT

Bone turnover markers (BTMs) are a series of protein or protein derivative biomarkers released during bone remodeling by osteoblasts or osteoclasts. BTMs can offer prognostic information on fracture risk that supplements radiographic measures of bone mass, but testing using BTMs has to take into account the large number of preanalytic factors and comorbid clinical conditions influencing BTM levels. BTMs respond rapidly to changes in bone physiology, therefore, they have utility in determining patient response to and compliance with therapies for osteoporosis.

SUMMARY

BTMs are a useful adjunct for the diagnosis and therapeutic monitoring of bone metabolic disorders, but their use has to be tempered by the known limitations in their clinical utility and preanalytic variables complicating interpretation.

Low Plasma Level of Leucine-Rich Repeat-Containing 17 (LRRc17) Is an Independent and Additive Risk Factor for Osteoporotic Fractures in Postmenopausal Women

A novel role of leucine-rich repeat-containing 17 (LRRc17), an LRR protein secreted by osteoblasts, as a negative regulator of receptor activator of NF-κB ligand-induced osteoclast differentiation was found. However, the clinical association between LRRc17 and osteoporotic fracture (OF) has not yet been investigated. We hypothesized that low circulating plasma level of LRRc17 might serve as an independent and additive risk factor for OF, including vertebral fractures (VF) and non-vertebral fractures (non-VF). In this case-control study, 102 OF cases and 102 age- and body mass index-matched controls (mean age, 63.2 years) were analyzed among 532 postmenopausal women. VF (n = 49) and non-VF (n = 60) participants were identified using lateral thoracolumbar radiographs and an interviewer-assisted questionnaire, respectively. Median LRRc17 levels were significantly lower in participants with any OF (117.5 versus 197.3 pg/mL, p < 0.001), VF (93.2 versus 172.4 pg/mL, p = 0.002), and non-VF (124.5 versus 206.9 pg/mL, p = 0.008) compared with the respective controls without fractures. The prevalence of OF increased from the highest LRRc17 tertile (≥228.5 pg/mL, 33.8%) to the lowest (<95.6 pg/mL, 63.2%). Each log unit decrease of LRRc17 was associated with greater risk of OF (odds ratio [OR] = 1.46; 95% confidence interval [CI] 1.10-1.96; p = 0.009) and VF (OR = 2.42; 95% CI 1.39-4.23; p = 0.002). Plasma LRRc17 significantly improved discrimination of OF, particularly VF, when added to models including clinical risk factors and bone mineral density according to the area under receiver operating characteristics curves (AUC 0.71 to 0.81, p = 0.036), category-free net reclassification improvement (0.79; 95% CI 0.37-1.21; p < 0.001), and integrated discrimination improvement (0.13; 95% CI 0.06-0.20; p < 0.001). Low plasma LRRc17 was an independent risk factor for OF, which improved risk stratification, particularly in the spines of postmenopausal women. © 2016 American Society for Bone and Mineral Research.

Cortical Bone Porosity: What Is It, Why Is It Important, and How Can We Detect It?

There is growing recognition of the role of micro-architecture in osteoporotic bone loss and fragility. This trend has been driven by advances in imaging technology, which have enabled a transition from measures of mass to micro-architecture. Imaging trabecular bone has been a key research focus, but advances in resolution have also enabled the detection of cortical bone micro-architecture, particularly the network of vascular canals, commonly referred to as 'cortical porosity.' This review aims to provide an overview of what this level of porosity is, why it is important, and how it can be characterized by imaging. Moving beyond a 'trabeculocentric' view of bone loss holds the potential to improve diagnosis and monitoring of interventions. Furthermore, cortical porosity is intimately linked to the remodeling process, which underpins bone loss, and thus a larger potential exists to improve our fundamental understanding of bone health through imaging of both humans and animal models.

Decreased Plasma Levels of Sclerostin But Not Dickkopf-1 are Associated with an Increased Prevalence of Osteoporotic Fracture and Lower Bone Mineral Density in Postmenopausal Korean Women

Although sclerostin (SOST) and Dickkopf-related protein 1 (DKK1) are major regulators in bone metabolism, their associations with osteoporotic fracture (OF) in Asians are inconclusive. Furthermore, there have been no clinical studies separately considering non-vertebral and vertebral fractures in terms of the blood levels of SOST and DKK1. Among 513 consecutive postmenopausal Korean women, we identified 103 cases defined as subjects with OF (i.e., non-vertebral and/or vertebral fractures). The controls were randomly selected from the remaining 410 subjects and matched 1:1 to cases according to both age and body mass index. Non-vertebral and morphological vertebral fractures were identified by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs, respectively. Bone mineral density (BMD) and plasma levels of SOST and DKK1 were measured. Plasma SOST levels were lower in subjects with OF than in the control group. Each standard deviation decrement of plasma SOST concentration was associated with a multivariable-adjusted odds ratio of 1.77 for any prevalent OF type. The odds for OF was 2.97-fold higher in subjects in the lowest SOST tertile compared with subjects in the highest SOST tertile. These associations remained significant when the non-vertebral and vertebral fractures were analyzed separately. However, prevalent OF was not associated with plasma DKK1 levels, regardless of the type of fracture and the adjustment model employed. Consistently, plasma SOST levels were positively related with BMD values at all measured skeletal sites, although this was not observed for DKK1. Circulating SOST but not DKK1 may be a potential biomarker for predicting bone health in Asians.

Vertebral body morphology is associated with incident lumbar vertebral fracture in postmenopausal women. The OFELY study

We investigate the predictive role of vertebral anterior cortical curvature and height heterogeneity in the occurrence of vertebral fractures in postmenopausal women. Women who will fracture had shorter vertebral height, greater heterogeneity of height than those who will not fracture, and their anterior vertebral body edge was less concave.

INTRODUCTION

Vertebral morphology has been demonstrated to be associated with further risk of fracture. The aim of this study was to analyze vertebral anterior cortical curvature (Ct.curv) and vertebral height heterogeneity in postmenopausal women before the occurrence of a vertebral fracture.

METHODS

This case-control study included 29 postmenopausal women who have underwent incident lumbar vertebral fractures (mean age 71 ± 9 years, mean time to fractures 9 ± 4 years), age-matched with 57 controls. From lateral X-rays of lumbar spine radiographs (T12 to L4), the following parameters were measured: (1) the posterior, middle, and anterior vertebral heights; (2) the heterogeneity of heights evaluated by the coefficient of variation of these three variables; (3) antero-posterior width, a 2D estimator of cross-sectional area; and (4) Ct.curv.

RESULTS

Mean vertebral heights were significantly lower among women who fractured than in controls (p < 0.05). The anterior and middle heights were significantly lower at L4 and L3 levels in fracture group (p = 0.02). The heterogeneity of vertebral height was significantly greater in the fracture group (p = 0.003). In addition, fractured patients had a significantly higher Ct.curv on L3 (p = 0.04). After adjustment for bone mineral density (BMD), only the heterogeneity of vertebral height remained significant (p = 0.005).

CONCLUSION

The current case-control study confirmed the association between vertebral height and occurrence of future vertebral fracture in postmenopausal women. The vertebrae with the smallest Ct.curv tended to fracture less often, and the heterogeneity of vertebral heights was associated with future fracture independently of BMD. An additional validation in a prospective study would be needed to confirm these initial results.

Diagnostic performance of osteocalcin measurements in patients with endogenous Cushing's syndrome

The aim of this study was to evaluate the diagnostic performance of osteocalcin (OC), as measured by automated electrochemiluminescence immunoassay (ECLIA), in identifying Cushing's syndrome (CS) in two separate populations: among obese and overweight subjects and among women of postmenopausal age with osteoporosis. Among the 106 referral patients with obesity, CS was confirmed in 42 cases. The patients of the referred population provided late-night salivary cortisol (LNSC), underwent low-dose dexamethasone suppression testing (DST) and were further evaluated until CS was pathologically confirmed. A threshold of OC-8.3 ng ml(-1) differentiated CS among obese and overweight subjects with a sensitivity of 73.8% (95% confidence interval (CI) 58.9-84.7) and a specificity of 96.9% (95% CI 89.3-99.1). The total area under the receiver operating characteristic curve (AUC) was 0.859 (95% CI 0.773-0.945), which was lower than LNSC or DST (P=0.01). In the retrospective portion of the study, the OC levels were evaluated in 67 subjects with newly diagnosed postmenopausal osteoporosis and in 23 patients (older than 45) with newly diagnosed CS and osteoporosis (presence of low traumatic fractures or T-score P-2.5). The diagnostic performance of OC for osteoporosis due to CS was within an AUC of 0.959 (95% CI 0.887-1.00). A threshold for OC of 8.3 ng ml-1 yielded a sensitivity of 95.4% (95% CI 78.2-99.2%) and a specificity of 98.5% (95% CI 92.0-99.7%). Thus, osteocalcin could be used in the diagnostic testing for endogenous hypercortisolism in patients referred to exclude CS and to identify CS among patients of postmenopausal age with osteoporosis.

In vivo evaluation of bone microstructure in humans: Clinically useful?

In vivo evaluation of bone microstructure with high-resolution peripheral quantitative tomography (HRpQCT) has been used for a decade in research settings. In this review, we examine the value this technique could have in clinical practice. Bone microstructure parameters obtained with HRpQCT are associated with prevalent fracture in men and women. In postmenopausal women, some parameters also predict incident fracture, independently of areal bone mineral density. In specific population groups including patients with diabetes, chronic kidney disease, glucocorticosteroid therapy and rheumatic diseases, abnormal microstructure parameters from HRpQCT have been reported. Findings from HRpQCT studies may also explain ethnic differences in bone fragility. Treatment monitoring has been challenging in the various clinical trials with available HRpQCT data. The improvements were of small magnitude but tended to be proportional to the potency of antiresorptive agents. Microfinite element analysis was a better predictor of treatment efficacy than the microarchitectural parameters. In conclusion, HRpQCT remains a valuable research tool, but more work is needed to be able to use it in clinical practice.

Osteoporosis Imaging in the Geriatric Patient

Given the expected rapid growth of the geriatric world population (=individuals aged >65 years) to 1.3 billion by 2050, age-related diseases such as osteoporosis and its sequelae, osteoporotic fractures, are on the rise. Areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) is the current gold standard to diagnose osteoporosis, to assess osteoporotic fracture risk, and to monitor treatment-induced BMD changes. However, most fragility fractures occur in patients with normal or osteopenic aBMD, indicating that factors beyond BMD impact bone strength. Recent developments in DXA technology such as TBS, VFA, and hip geometry analysis are now available to assess some of these non-BMD parameters from the DXA image. This review will discuss the use of DXA and DXA-assisted technologies and their respective advantages and disadvantages. Special attention is given to if and how each method is indicated in the geriatric population, and the latest ISCD 2015 guidelines have been incorporated.

Age-related changes in bone strength from HR-pQCT derived microarchitectural parameters with an emphasis on the role of cortical porosity

The high resolution peripheral computed tomography (HR-pQCT) technique has seen recent developments with regard to the assessment of cortical porosity. In this study, we investigated the role of cortical porosity on bone strength in a large cohort of women. The distal radius and distal tibia were scanned by HR-pQCT. We assessed bone strength by estimating the failure load by microfinite element analysis (μFEA), with isotropic and homogeneous material properties. We built a multivariate model to predict it, using a few microarchitecture variables including cortical porosity. Among 857 Caucasian women analyzed with μFEA, we found that cortical and trabecular properties, along with the failure load, impaired slightly with advancing age in premenopausal women, the correlations with age being modest, with |rage| ranging from 0.14 to 0.38. After the onset of the menopause, those relationships with age were stronger for most parameters at both sites, with |rage| ranging from 0.10 to 0.64, notably for cortical porosity and failure load, which were markedly deteriorated with increasing age. Our multivariate model using microarchitecture parameters revealed that cortical porosity played a significant role in bone strength prediction, with semipartial r(2)=0.22 only at the tibia in postmenopausal women. In conclusion, in our large cohort of women, we observed a small decline of bone strength at the tibia before the onset of menopause. We also found an age-related increase of cortical porosity at both scanned sites in premenopausal women. In postmenopausal women, the relatively high increase of cortical porosity accounted for the decline in bone strength only at the tibia.

Type 2 diabetes and the skeleton: new insights into sweet bones

Substantial evidence shows that skeletal fragility should be considered among the complications associated with type 2 diabetes. Individuals with type 2 diabetes have increased fracture risk, despite normal bone mineral density (BMD) and high BMI-factors that are generally protective against fractures. The mechanisms underlying skeletal fragility in diabetes are not completely understood, but are multifactorial and likely include effects of obesity, hyperglycaemia, oxidative stress, and accumulation of advanced glycation end products, leading to altered bone metabolism, structure, and strength. Clinicians should be aware that BMD measurements underestimate fracture risk in people with type 2 diabetes, and that new treatments for diabetes, with neutral or positive effects on skeletal health, might play a part in the management of diabetes in those at high risk of fracture. Data for the optimum management of osteoporosis in patients with type 2 diabetes are scarce, but in the absence of evidence to the contrary, physicians should follow guidelines established for postmenopausal osteoporosis.

Bone turnover biomarkers and risk of osteoporotic hip fracture in an Asian population

While epidemiologic studies suggest that bone turnover biomarkers may predict hip fracture risk, findings are inconsistent and Asian data are lacking. We conducted a matched case-control (1:1) study nested in the Singapore Chinese Health Study, a population-based prospective cohort of Chinese men and women (45-74years) recruited from 1993 to 1998 in Singapore. One hundred cases with incident hip fracture and 100 individually matched controls were randomly selected from 63,257 participants. Serum bone turnover biomarkers, namely bone alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I N propeptide (PINP), N-terminal and C-terminal crosslinking telopeptide of type I collagen (NTX-I and CTX-I) were measured using immunoassays. Hip fracture cases had significantly higher serum levels of OC, PINP, CTX-I and NTX-I than controls (p<0.05). There was a dose-dependent positive relationship between OC, PINP, CTX-I and NTX-I and risk of hip fracture (all Ps for trend≤0.006), where the risk was significantly increased by 4.32-8.23 folds for the respective BTM [Quartile (Q) 4 vs. Q1]. The odds ratio [OR (95% CI)] at the highest quartile (Q4) was 6.63 (2.02-21.18) for PINP and 4.92 (1.67-14.51) for CTX-I. The joint effect of PINP and CTX-I showed a 7-fold increase in risk (OR: 7.36; 95% CI: 2.53-21.41) comparing participants with higher levels of PINP (Q4) and CTX-I (Q3-Q4) to those with low levels of PINP (Q1-Q3) and CTX-I (Q1-Q2). Our data demonstrated that higher serum levels of bone turnover biomarkers were associated with increased risk of hip fracture in an Asian population.