Quantitative ultrasound and dual-energy X-ray absorptiometry in the prediction of fragility fracture in men

Investigating the causal relationship between ankylosing spondylitis and osteoporosis in the European population: a bidirectional Mendelian randomization study

Background

Ankylosing Spondylitis (AS) is an inflammatory condition affecting the spine, which may lead to complications such as osteoporosis (OP). Many observational studies have demonstrated a close relationship with strong evidence between OP and AS. The combination of AS and OP is already an indisputable fact, but the exact mechanism of AS complicated with OP is unclear. To better prevent and treat OP in patients with AS, it is necessary to understand the specific mechanism of OP in these patients. In addition, there is a study showing that OP is a risk factor for AS, but the causal relationship between them is not yet clear. Therefore, we conducted a bidirectional Mendelian randomization (MR) analysis to determine whether there is a direct causal effect between AS and OP and to investigate the co-inherited genetic information between the two.

Methods

Bone mineral density (BMD) was used as a phenotype for OP. The AS dataset was taken from the IGAS consortium and included people of European ancestry (9,069 cases and 13,578 controls). BMD datasets were obtained from the GEFOS consortium, a large GWAS meta-analysis study, and the UK Biobank and were categorized based on site (total body (TB): 56,284 cases; lumbar spine (LS): 28,498 cases; femoral neck (FN): 32,735 cases; forearm (FA): 8,143 cases; and heel: 265,627 cases) and age (0-15: 11,807 cases; 15-30: 4,180 cases; 30-45: 10,062 cases; 45-60: 18,062 cases; and over 60: 22,504 cases).To obtain the casual estimates, the inverse variant weighted (IVW) method was mainly used due to its good statistical power and robustness. The presence of heterogeneity was evaluated using Cochran's Q test. Pleiotropy was assessed utilizing MR-Egger regression and MR-pleiotropy residual sum and outlier (MR-PRESSO).

Results

Generally, there were no significant causal associations between genetically predicted AS and decreased BMD levels. The results of MR-Egger regression, Weighted Median, and Weighted Mode methods were consistent with those of the IVW method. However, there was a sign of a connection between genetically elevated BMD levels and a decreased risk of AS (Heel-BMD: OR = 0.879, 95% CI: 0.795-0.971, P = 0.012; Total-BMD: OR = 0.948, 95% CI: 0.907-0.990, P = 0.017; LS-BMD: OR = 0.919, 95% CI: 0.861-0.980, P = 0.010). The results were confirmed to be reliable by sensitivity analysis.

Conclusion

This MR study found that the causal association between genetic liability to AS and the risk of OP or lower BMD in the European population was not evident, which highlights the second effect (e.g., mechanical reasons such as limited movement) of AS on OP. However, genetically predicted decreased BMD/OP is a risk factor for AS with a causal relationship, implying that patients with OP should be aware of the potential risk of developing AS. Moreover, OP and AS share similar pathogenesis and pathways.

Association of insulin resistance with bone mineral density in a nationwide health check-up population in China

INTRODUCTION

Insulin resistance (IR) is closely associated with cardio-metabolic diseases. However, the impact of IR on bone mass remains obscure. The present study is to evaluate the association between the triglyceride-glucose (TyG) indicated IR and bone mass in a nationwide health check-up population in China.

METHODS

We conducted a retrospective cross-sectional study including 788,247 participants and a longitudinal cohort study in 8770 participants who had repeated measurements of TyG index and bone mass in at least a 2-year follow-up period. The restricted cubic splines and logistic models were used to analyze the association between IR and bone mass in the cross-sectional study. The Cox model was applied to evaluate the relationship between baseline IR and the subsequent incidence of low bone mass and osteoporosis in the longitudinal study.

RESULTS

In the cross-sectional study, the TyG index had positive correlations with low bone mass, osteoporosis, or both after adjusting for confounding factors (all P < 0.001). In the longitudinal cohort study, the baseline TyG index was significantly associated with the incidence of low bone mass, osteoporosis, or both during the follow-up period, with hazard ratios (HRs) of 1.56 (95 % confidence interval [CI]: 1.25, 1.93, P < 0.05), 1.66 (95%CI: 1.06, 2.59, P < 0.05), and 1.55 (95%CI: 1.27, 1.88, P < 0.05) after adjusting for confounding factors, respectively.

CONCLUSIONS

These results suggest that IR indicated by TyG is significantly associated with an increased risk of low bone mass and osteoporosis. Therefore, bone mass monitoring and early prevention strategies may be needed in individuals with IR to prevent the occurrence of low bone mass and osteoporosis.

Regular Exercise Decreases the Risk of Osteoporosis in Postmenopausal Women

Regular exercise can regulate bone maintenance and improve bone health. However, large-scale epidemiological studies on the association between regular exercise and incident osteoporosis in menopausal women are still lacking. We aimed to examine the relationship between exercise and the risk of osteoporosis in menopausal women. In cross-sectional analysis, we enrolled 30,046 postmenopausal women with available information from the database of the Taiwan Biobank (TWB). We divided them into two groups according to their status of regular exercise, i.e., no exercise and regular exercise groups. A t-score of -2.5 or more standard deviations (SDs) below that of a young adult was defined as osteoporosis. Logistic regression after adjusting for confounding factors was used to analyze the association between regular exercise and the prevalence of osteoporosis. Furthermore, the risk of incident osteoporosis development was analyzed in a longitudinal cohort of 6,785 postmenopausal women without osteoporosis at baseline using a Kaplan-Meier analysis and a log-rank test. The mean age of subjects in the cross-sectional cohort was 59 years old. Fifty-six percent of them were exercising regularly. Osteoporosis was observed in 1,886 (14.2%) and 2,254 (13.4%) participants in the no exercise and regular exercise groups. Lower risk of osteoporosis was noted in postmenopausal women with regular exercise when compared with those without regular exercise [odds ratio (OR), 0.76; 95% confidence interval (95% CI), 0.71-0.81]. In the longitudinal cohort, incident osteoporosis was found in 430 (10.5%) women with regular exercise and 299 (11.2%) women without exercise during a mean follow-up of 45 months. Cox regression analysis revealed that the risk for incident osteoporosis was lower in postmenopausal women with regular exercise than those without exercise [hazard ratio (HR), 0.83; 95% CI, 0.71-0.97]. Our study suggests that regular exercise is associated with a reduced risk of osteoporosis in postmenopausal women and strengthens the importance of exercise for the prevention of osteoporosis.

Hyperuricemia and Its Association with Osteoporosis in a Large Asian Cohort

In this paper, we aimed to examine the protective role of hyperuricemia in the prevalence of osteoporosis in a large Asian cohort. A total of 119,037 participants from 29 recruitment centers in Taiwan were enrolled onto our study. Participants with serum uric acid greater than 7.0 mg/dL in men and 6.0 mg/dL in women were classified as the hyperuricemia group whereas the others were the control group. The mean age of all participants was 50; there were 23,114 subjects (19%) with hyperuricemia. Osteoporosis was observed in 8243 (9%) and 1871 (8%) participants in the control and hyperuricemia groups, respectively. After adjusting for confounders, a lower risk of osteoporosis was found in the hyperuricemia group compared with the control group (odds ratio, 0.916; 95% confidence interval, 0.864 to 0.970). A subgroup analysis showed that hyperuricemia was associated with a lower risk of osteoporosis in females, but not in males. Women with serum uric acid greater than 8.0 mg/dL were not associated with a greater risk of osteoporosis. Our study suggests that hyperuricemia decreases the risk of osteoporosis in females, but not in males. The protective role was no longer apparent when the serum uric acid level was greater than 8 mg/dL.

Biobank data for studying the genetic architecture of osteoporosis and developing genetic risk scores

Osteoporosis is a chronic systemic disease of the skeleton, characterized by a decrease in bone mass and an impairment of bone microarchitecture, which can lead to a decrease in bone strength and an increase in the risk of minor trauma fractures. Osteoporosis is diagnosed on the basis of bone mineral density (BMD). BMD is characterized by high heritability that ranges according to various sources from 50 to 85%. As in the case of other complex traits, the most common approach to searching for genetic variants that affect BMD is a genome-wide association study. The lower effect size or frequency of a variant is, the larger the sample size is required to achieve statistically significant data on associations. Therefore, the studies involving hundreds of thousands of participants based on biobank data can identify the largest number of variants associated with BMD. In addition, biobank data are used in the development of genetic risk scores for osteoporosis that can be used both in combination with existing prognosis algorithms and independently of them. The aim of this review was to present the most significant studies of osteoporosis genetics, including those based on biobank data and genome-wide association studies, as well as studies on the genetic risk scores and the contribution of rare variants.

Quantitative Ultrasound (QUS) in the Management of Osteoporosis and Assessment of Fracture Risk: An Update

Quantitative ultrasound (QUS) presents a low cost and readily available alternative to DXA measurements of bone mineral density (BMD) for osteoporotic fracture risk assessment. It is performed in a variety of skeletal sites, among which the most widely investigated and clinically used are first the calcaneus and then the radius. Nevertheless, there is still uncertainty in the incorporation of QUS in the clinical management of osteoporosis as the level of clinical validation differs substantially upon the QUS models available. In fact, results from a given QUS device can unlikely be extrapolated to another one, given the technological differences between QUS devices. The use of QUS in clinical routine to identify individuals at low or high risk of fracture could be considered primarily when central DXA is not easily available. In this later case, it is recommended that QUS bone parameters are used in combination with established clinical risk factors for fracture. Currently, stand-alone QUS is not recommended for treatment initiation decision making or follow-up. As WHO classification of osteoporosis thresholds cannot apply to QUS, thresholds specific for given QUS devices and parameters need to be determined and cross-validated widely to have a well-defined and certain use of QUS in osteoporosis clinical workflow. Despite the acknowledged current clinical limitations for QUS to be used more widely in daily routine, substantial progresses have been made and new results are promising.

Identification of New Genes and Loci Associated With Bone Mineral Density Based on Mendelian Randomization

Bone mineral density (BMD) is a complex and highly hereditary trait that can lead to osteoporotic fractures. It is estimated that BMD is mainly affected by genetic factors (about 85%). BMD has been reported to be associated with both common and rare variants, and numerous loci related to BMD have been identified by genome-wide association studies (GWAS). We systematically integrated expression quantitative trait loci (eQTL) data with GWAS summary statistical data. We mainly focused on the loci, which can affect gene expression, so Summary data-based Mendelian randomization (SMR) analysis was implemented to investigate new genes and loci associated with BMD. We identified 12,477 single-nucleotide polymorphisms (SNPs) regulating 564 genes, which are associated with BMD. The genetic mechanism we detected could make a contribution in the density of BMD in individuals and play an important role in understanding the pathophysiology of cataclasis.

A Distinctive Human Metabolomics Alteration Associated with Osteopenic and Osteoporotic Patients

Osteoporosis is a common progressive metabolic bone disease resulting in decreased bone mineral density (BMD) and a subsequent increase in fracture risk. The known bone markers are not sensitive and specific enough to reflect the balance in the bone metabolism. Finding a metabolomics-based biomarker specific for bone desorption or lack of bone formation is crucial for predicting bone health earlier. This study aimed to investigate patients' metabolomic profiles with low BMD (LBMD), including those with osteopenia (ON) and osteoporosis (OP), compared to healthy controls. An untargeted mass spectrometry (MS)-based metabolomics approach was used to analyze serum samples. Results showed a clear separation between patients with LBMD and control (Q² = 0.986, R² = 0.994), reflecting a significant difference in the dynamic of metabolic processes between the study groups. A total of 116 putatively identified metabolites were significantly associated with LBMD. Ninety-four metabolites were dysregulated, with 52 up- and 42 downregulated in patients with LBMD compared to controls. Histidine metabolism, aminoacyl-tRNA biosynthesis, glyoxylate, dicarboxylate metabolism, and biosynthesis of unsaturated fatty acids were the most common metabolic pathways dysregulated in LBMD. Furthermore, 35 metabolites were significantly dysregulated between ON and OP groups, with 11 up- and 24 downregulated in ON compared to OP. Among the upregulated metabolites were 3-carboxy-4-methyl-5-propyl-2-2furanopropionic acid (CMPF) and carnitine derivatives (i.e., 3-hydroxy-11-octadecenoylcarnitine, and l-acetylcarnitine), whereas phosphatidylcholine (PC), sphingomyelin (SM), and palmitic acid (PA) were among the downregulated metabolites in ON compared to OP. This study would add a layer to understanding the possible metabolic alterations associated with ON and OP. Additionally, this identified metabolic panel would help develop a prediction model for bone health and OP progression.

Twelve years of GWAS discoveries for osteoporosis and related traits: advances, challenges and applications

Osteoporosis is a common skeletal disease, affecting ~200 million people around the world. As a complex disease, osteoporosis is influenced by many factors, including diet (e.g. calcium and protein intake), physical activity, endocrine status, coexisting diseases and genetic factors. In this review, we first summarize the discovery from genome-wide association studies (GWASs) in the bone field in the last 12 years. To date, GWASs and meta-analyses have discovered hundreds of loci that are associated with bone mineral density (BMD), osteoporosis, and osteoporotic fractures. However, the GWAS approach has sometimes been criticized because of the small effect size of the discovered variants and the mystery of missing heritability, these two questions could be partially explained by the newly raised conceptual models, such as omnigenic model and natural selection. Finally, we introduce the clinical use of GWAS findings in the bone field, such as the identification of causal clinical risk factors, the development of drug targets and disease prediction. Despite the fruitful GWAS discoveries in the bone field, most of these GWAS participants were of European descent, and more genetic studies should be carried out in other ethnic populations to benefit disease prediction in the corresponding population.

Development of a polygenic risk score to improve screening for fracture risk: A genetic risk prediction study

BACKGROUND

Since screening programs identify only a small proportion of the population as eligible for an intervention, genomic prediction of heritable risk factors could decrease the number needing to be screened by removing individuals at low genetic risk. We therefore tested whether a polygenic risk score for heel quantitative ultrasound speed of sound (SOS)-a heritable risk factor for osteoporotic fracture-can identify low-risk individuals who can safely be excluded from a fracture risk screening program.

METHODS AND FINDINGS

A polygenic risk score for SOS was trained and selected in 2 separate subsets of UK Biobank (comprising 341,449 and 5,335 individuals). The top-performing prediction model was termed "gSOS", and its utility in fracture risk screening was tested in 5 validation cohorts using the National Osteoporosis Guideline Group clinical guidelines (N = 10,522 eligible participants). All individuals were genome-wide genotyped and had measured fracture risk factors. Across the 5 cohorts, the average age ranged from 57 to 75 years, and 54% of studied individuals were women. The main outcomes were the sensitivity and specificity to correctly identify individuals requiring treatment with and without genetic prescreening. The reference standard was a bone mineral density (BMD)-based Fracture Risk Assessment Tool (FRAX) score. The secondary outcomes were the proportions of the screened population requiring clinical-risk-factor-based FRAX (CRF-FRAX) screening and BMD-based FRAX (BMD-FRAX) screening. gSOS was strongly correlated with measured SOS (r2 = 23.2%, 95% CI 22.7% to 23.7%). Without genetic prescreening, guideline recommendations achieved a sensitivity and specificity for correct treatment assignment of 99.6% and 97.1%, respectively, in the validation cohorts. However, 81% of the population required CRF-FRAX tests, and 37% required BMD-FRAX tests to achieve this accuracy. Using gSOS in prescreening and limiting further assessment to those with a low gSOS resulted in small changes to the sensitivity and specificity (93.4% and 98.5%, respectively), but the proportions of individuals requiring CRF-FRAX tests and BMD-FRAX tests were reduced by 37% and 41%, respectively. Study limitations include a reliance on cohorts of predominantly European ethnicity and use of a proxy of fracture risk.

CONCLUSIONS

Our results suggest that the use of a polygenic risk score in fracture risk screening could decrease the number of individuals requiring screening tests, including BMD measurement, while maintaining a high sensitivity and specificity to identify individuals who should be recommended an intervention.

The Effect of Plasma Lipids and Lipid-Lowering Interventions on Bone Mineral Density: A Mendelian Randomization Study

Several epidemiological studies have reported a relationship between statin treatment and increased bone mineral density (BMD) and reduced fracture risk, but the mechanism underlying the purported relationship is unclear. We used Mendelian randomization (MR) to assess whether this relationship is explained by a specific effect in response to statin use or by a general effect of lipid lowering. We utilized 400 single-nucleotide polymorphisms (SNPs) robustly associated with plasma lipid levels as exposure. The outcome results were obtained from a heel estimated BMD (eBMD) genomewide association study (GWAS) from the UK Biobank and dual-energy X-ray absorptiometry (DXA) BMD at four body sites and fracture GWAS from the GEFOS consortium. We performed univariate and multivariable MR analyses of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride levels on BMD and fracture. Univariate MR analyses suggested a causal effect of LDL-C on eBMD (β = -0.06; standard deviation change in eBMD per standard deviation change in LDL-C, 95% confidence interval [CI] = -0.08 to -0.04; p = 4 × 10^-6 ), total body BMD (β = -0.05, 95% CI = -0.08 to -0.01, p = 6 × 10^-3 ) and potentially on lumbar spine BMD. Multivariable MR suggested that the effects of LDL-C on eBMD and total body BMD were independent of HDL-C and triglycerides. Sensitivity MR analyses suggested that the LDL-C results were robust to pleiotropy. MR analyses of LDL-C restricted to SNPs in the HMGCR region showed similar effects on eBMD (β = -0.083; -0.132 to -0.034; p = .001) to those excluding these SNPs (β = -0.063; -0.090 to -0.036; p = 8 × 10^-6 ). Bidirectional MR analyses provided some evidence for a causal effect of eBMD on plasma LDL-C levels. Our results suggest that effects of statins on eBMD and total body BMD are at least partly due to their LDL-C lowering effect. Further studies are required to examine the potential role of modifying plasma lipid levels in treating osteoporosis. © 2020 American Society for Bone and Mineral Research.

Calcaneal quantitative ultrasound has a role in out ruling low bone mineral density in axial spondyloarthropathy

OBJECTIVE

The aim of this study was to investigate the role of quantitative ultrasound (QUS) of the calcaneus in screening for osteoporosis in adults with axial spondyloarthropathy (axSpA).

METHOD

Postmenopausal women and men over 50 years with axSpA were recruited for this observational cross-sectional study. Dual-energy x-ray absorptiometry (DXA) assessed bone mineral density (BMD) of the spine and hip. QUS of the calcaneus produced broadband ultrasound attenuation (BUA), speed of sound (SOS), stiffness index (SI), and T-scores. Receiver-operating characteristics (ROC) curve analysis determined the ability of QUS to discriminate between low and normal BMD. Thresholds were identified to (1) out rule low BMD, (2) identify osteoporosis, and (3) identify low BMD. The number of DXAs which could be avoided using this approach was calculated.

RESULTS

56 participants were analyzed. BUA, SI, and T-score QUS parameters correlated with BMD by DXA; SOS did not. All QUS parameters had the ability to discriminate between low and normal BMD (area under the curve varied from 0.695 to 0.779). QUS identified individuals without low BMD with 90% confidence, with BUA performing best (sensitivity 93%, negative predictive value 86%). Using QUS as a triage tool, up to 27% of DXA assessments could have been avoided. QUS could not confidently identify individuals with osteoporosis.

CONCLUSIONS

QUS of the calcaneus confidently out ruled low BMD in individuals with axSpA, reducing the need for onward DXA referral by up to 27%. QUS is promising as a non-invasive triage tool in the assessment of osteoporosis in adults with axSpA.Key Points• Osteoporosis is common in axial spondyloarthropathy (SpA), but evaluation of bone health is suboptimal in this population.• Quantitative ultrasound (QUS) of the calcaneus can out rule low bone mineral density in individuals with axial SpA, reducing the need for DXA assessment.• QUS is a promising non-invasive triage tool in the assessment of bone health in axial SpA.

Bone Health and Its Relationship with Impact Loading and the Continuity of Physical Activity throughout School Periods

Bone is influenced by physical activity (PA) throughout life, but childhood and adolescence provide a key opportunity to maximize peak bone mass. Thus, it is important to identify the relationship between PA practiced in childhood and young adulthood to design a promotion plan for bone health. The purpose of this study was to analyze the relationship between different impact-loading PAs (and their continuity throughout school periods from childhood to young adulthood) and bone stiffness index (SI). In this cross-sectional study, which was conducted on 145 university students aged 18-21 years, bone measurements were measured by quantitative ultrasonometry (QUS), and PA information was recalled using a self-administered questionnaire. Associations between the SI and the impact of PA performed during secondary school (p = 0.027), high school (p = 0.002), and university (p = 0.016) periods were observed. The continuity of PA over a longer period of time was related to a higher SI (p = 0.007). Those who practiced PA throughout all school periods had a higher SI than those who practiced during primary school only (p = 0.038) or through primary and secondary schools (p = 0.009). These results suggest that impact-loading PA practiced during different school periods is related to higher values of the SI. Therefore, continuous PA from an early age may be an important contributing factor to achieving and maintaining adequate bone health.

Meta-Analysis of Genome-Wide Association Studies Identifies Three Loci Associated With Stiffness Index of the Calcaneus

The stiffness index (SI) from quantitative ultrasound measurements is a good indicator of BMD and may be used to predict the risk of osteoporotic fracture. We conducted a genomewide association study (GWAS) for SI using 7742 individuals from the Taiwan Biobank, followed by a replication study in a Korean population (n = 2955). Approximately 6.1 million SNPs were subjected to association analysis, and SI-associated variants were identified. We further conducted a meta-analysis of Taiwan Biobank significant SNPs with a Korean population-based cohort. Candidate genes were prioritized according to epigenetic annotations, gene ontology, protein-protein interaction, GWAS catalog, and expression quantitative trait loci analyses. Our results revealed seven significant single-nucleotide polymorphisms (SNPs) within three loci: 7q31.31, 17p13.3, and 11q14.2. Conditional analysis showed that three SNPs, rs2536195 (CPED1/WNT16), rs1231207 (SMG6), and rs4944661 (LOC10050636/TMEM135), were the most important signals within these regions. The associations for the three SNPs were confirmed in a UK Biobank estimated BMD GWAS; these three cytobands were replicated successfully after a meta-analysis with a Korean population cohort as well. However, two SNPs were not replicated. After prioritization, we identified two novel genes, RAB15 and FNTB, as strong candidates for association with SI. Our study identified three SI-associated SNPs and two novel SI-related genes. Overall, these results provide further insight into the genetic architecture of osteoporosis. Further studies in larger East Asian populations are needed. © 2019 American Society for Bone and Mineral Research.

Calcaneal Broadband Ultrasound Attenuation and Speed of Sound Measurements in a Population of Nigerian Children: Reference Data and the Influence of Sociodemographic Variables

OBJECTIVES

The aim of our study was to establish a reference database of calcaneal broadband ultrasound attenuation (BUA) and the speed of sound (SOS) in a healthy Nigerian population of children aged 6 to 14 years and also to investigate the influence of sociodemographic and anthropometric variables on them.

METHODS

The BUA and SOS of 1016 healthy children were measured by quantitative ultrasound densitometry. Height and weight were measured with a stadiometer and weighing balance, respectively, whereas the sociodemographic parameters of the participants were collected on a semistructured questionnaire. A multiple regression model using stepwise selection and Pearson correlation coefficients were used to examine the relationship between the ultrasound parameters and sociodemographic and anthropometric parameters. Comparisons between various age groups were made by analysis of variance.

RESULTS

The mean BUA and SOS ± SD of the participants were 60.57 ± 16.21 dB/MHz and 1563.48 ± 21.74 m/s, respectively, for boys and 58.18 ± 15.16 dB/MHz and 1560.03 ± 22.32 m/s for girls. The BUA in both sexes was positively influenced by age and weight (P < .05), whereas only the father's educational status was its predictor (P < .05) in the boys. For the girls, the family size and mother's educational status were predictors of the BUA (P < .05). The SOS was marginally influenced by age and family size in the boys (P < .05), whereas the father's educational status was the predictor in the girls.

CONCLUSIONS

The established BUA and SOS values in this study are baseline values, and further study, which would also involve data from a large number of Nigerian children, would be needed to support their effectiveness as reference values.

Associations between radius low-frequency axial ultrasound velocity and bone fragility in elderly men and women

An exploratory study in elderly women and men from the Geneva Retirees Cohort indicates that low-frequency quantitative ultrasound measurement at the radius captures aBMD, bone size, and cortical tissue mineral density and might be used for screening purposes prior to DXA to evaluate fracture risk_. INTRODUCTION: The contribution of distal radius bone mineral density (BMD) and cortical microstructure to fracture risk has recently been demonstrated. In this exploratory study, we investigated whether low-frequency quantitative ultrasound measurement at the distal radius may capture the peripheral determinants of bone fragility assessed with dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT).

METHODS

Low-frequency velocity (V_LF) was measured at the radius using OsCare Sono®, a portable axial transmission ultrasonometer, in 271 community-dwelling postmenopausal women and men (age 71.5 ± 1.4 years) from the Geneva Retirees Cohort. Cortical (Ct) and trabecular (Tb) volumetric (v) BMD and microstructure at the distal radius were assessed by HR-pQCT, in addition to areal (a) BMD by DXA, at the same time point.

RESULTS

V_LF was highly correlated with aBMD at the distal third radius (r = 0.72, p < 0.001). For microstructure parameters, the highest correlation was observed with cortical area (r = 0.59, p < 0.001). V_LF also captured bone geometry (total area) and cortical tissue mineral density independently of aBMD. In models adjusted for age and sex, V_LF was significantly associated with prevalent low-trauma fractures [OR 95%CI for one SD decrease of V_LF 1.50 (1.05, 2.14), p = 0.024], with discrimination performance comparable to femoral neck or distal radius aBMD.

CONCLUSION

Measurement of V_LF at the radius captures aBMD, bone size, and cortical tissue mineral density and might be used for screening purposes prior to DXA to evaluate fracture risk_.

New Insights Into Monogenic Causes of Osteoporosis

Osteoporosis, characterized by deteriorated bone microarchitecture and low bone mineral density, is a chronic skeletal disease with high worldwide prevalence. Osteoporosis related to aging is the most common form and causes significant morbidity and mortality. Rare, monogenic forms of osteoporosis have their onset usually in childhood or young adulthood and have specific phenotypic features and clinical course depending on the underlying cause. The most common form is osteogenesis imperfecta linked to mutations in COL1A1 and COL1A2, the two genes encoding type I collagen. However, in the past years, remarkable advancements in bone research have expanded our understanding of the intricacies behind bone metabolism and identified novel molecular mechanisms contributing to skeletal health and disease. Especially high-throughput sequencing techniques have made family-based studies an efficient way to identify single genes causative of rare monogenic forms of osteoporosis and these have yielded several novel genes that encode proteins partaking in type I collagen modification or regulating bone cell function directly. New forms of monogenic osteoporosis, such as autosomal dominant osteoporosis caused by WNT1 mutations or X-linked osteoporosis due to PLS3 mutations, have revealed previously unidentified bone-regulating proteins and clarified specific roles of bone cells, expanded our understanding of possible inheritance mechanisms and paces of disease progression, and highlighted the potential of monogenic bone diseases to extend beyond the skeletal tissue. The novel gene discoveries have introduced new challenges to the classification and diagnosis of monogenic osteoporosis, but also provided promising new molecular targets for development of pharmacotherapies. In this article we give an overview of the recent discoveries in the area of monogenic forms of osteoporosis, describing the key cellular mechanisms leading to skeletal fragility, the major recent research findings and the essential challenges and avenues in future diagnostics and treatments.

Mouse Models and Online Resources for Functional Analysis of Osteoporosis Genome-Wide Association Studies

Osteoporosis is a complex genetic disease in which the number of loci associated with the bone mineral density, a clinical risk factor for fracture, has increased at an exponential rate in the last decade. The identification of the causative variants and candidate genes underlying these loci has not been able to keep pace with the rate of locus discovery. A large number of tools and data resources have been built around the use of the mouse as model of human genetic disease. Herein, we describe resources available for functional validation of human Genome Wide Association Study (GWAS) loci using mouse models. We specifically focus on large-scale phenotyping efforts focused on bone relevant phenotypes and repositories of genotype-phenotype data that exist for transgenic and mutant mice, which can be readily mined as a first step toward more targeted efforts designed to deeply characterize the role of a gene in bone biology.

Expression Quantitative Trait Locus Study of Bone Mineral Density GWAS Variants in Human Osteoclasts

Osteoporosis is a complex disease with a strong genetic component. Genomewide association studies (GWAS) have been very successful at identifying common genetic variants associated with bone parameters. A recently published study documented the results of the largest GWAS for bone mineral density (BMD) performed to date (n = 142,487), identifying 307 conditionally independent single-nucleotide polymorphisms (SNPs) as associated with estimated BMD (eBMD) at the genomewide significance level. The vast majority of these variants are non-coding SNPs. Expression quantitative trait locus (eQTL) studies using disease-specific cell types have increasingly been integrated with the results from GWAS to identify genes through which the observed GWAS associations are likely mediated. We generated a unique human osteoclast-specific eQTL data set using cells differentiated in vitro from 158 participants. We then used this resource to characterize the 307 recently identified BMD GWAS SNPs for association with nearby genes (±500 kb). After correction for multiple testing, 24 variants were found to be significantly associated with the expression of 32 genes in the osteoclast-like cells. Bioinformatics analysis suggested that these variants and those in strong linkage disequilibrium with them are enriched in regulatory regions. Several of the eQTL associations identified are relevant to genes that present strongly as having a role in bone, particularly IQGAP1, CYP19A1, CTNNB1, and COL6A3. Supporting evidence for many of the associations was obtained from publicly available eQTL data sets. We have also generated strong evidence for the presence of a regulatory region on chromosome 15q21.2 relevant to both the GLDN and CYP19A1 genes. In conclusion, we have generated a unique osteoclast-specific eQTL resource and have used this to identify 32 eQTL associations for recently identified BMD GWAS loci, which should inform functional studies of osteoclast biology. © 2018 American Society for Bone and Mineral Research.

Physical Activity, Physical Fitness, Body Composition, and Nutrition Are Associated with Bone Status in University Students

Understanding the modifiable factors that improve and maximize peak bone mass at an early age is necessary to design more effective intervention programs to prevent osteoporosis. To identify these modifiable factors, we analyzed the relationship of physical activity (PA), physical fitness, body composition, and dietary intake with bone stiffness index (SI), measured by quantitative ultrasonometry in young university students (18–21 years). Moderate-to-vigorous PA (MVPA) was the strongest predictor of SI (β = 0.184; p = 0.035). SI was most closely related with very vigorous PA in males (β = 0.288; p = 0.040) and with the number of steps/day in females (β = 0.319; p = 0.002). An association between thigh muscle and SI was consistent in both sexes (β = 0.328; p < 0.001). Additionally, extension maximal force was a bone SI predictor factor in females (β = 0.263; p = 0.016) independent of thigh muscle perimeter. Calcium intake was the only nutrition parameter that had a positive relationship with SI (R = 0.217; p = 0.022). However, it was not included as a predictor for SI in our regression models. This study identifies predictors of bone status in each sex and indicates that muscle and bone interrelate with PA and fitness in young adults.

Identification of 153 new loci associated with heel bone mineral density and functional involvement of GPC6 in osteoporosis

Osteoporosis is a common disease diagnosed primarily by measurement of bone mineral density (BMD). We undertook a genome-wide association study (GWAS) in 142,487 individuals from the UK Biobank to identify loci associated with BMD as estimated by quantitative ultrasound of the heel. We identified 307 conditionally independent single-nucleotide polymorphisms (SNPs) that attained genome-wide significance at 203 loci, explaining approximately 12% of the phenotypic variance. These included 153 previously unreported loci, and several rare variants with large effect sizes. To investigate the underlying mechanisms, we undertook (1) bioinformatic, functional genomic annotation and human osteoblast expression studies; (2) gene-function prediction; (3) skeletal phenotyping of 120 knockout mice with deletions of genes adjacent to lead independent SNPs; and (4) analysis of gene expression in mouse osteoblasts, osteocytes and osteoclasts. The results implicate GPC6 as a novel determinant of BMD, and also identify abnormal skeletal phenotypes in knockout mice associated with a further 100 prioritized genes.

Bone mineral density in people living with HIV: a narrative review of the literature

Bone health status is largely absent in South Africa, the main reasons being the absence and cost-effectiveness of specific screening equipment for assessing bone mineral density (BMD). Various risk factors seem to play a role, some of which can be modified to change bone health status. Urbanisation is also a public health concern. Changing nutritional, as well as social behaviour, play integral roles in the prevalence and incidence of decreased BMD. Furthermore, human immunodeficiency virus (HIV) specifically, has a negative impact on BMD and although highly active antiretroviral therapy increases the prognosis for HIV-infected individuals, BMD still seem to decrease further. Dual energy X-ray absorptiometry is considered the gold standard for BMD assessment; however, recent developments have provided more cost-effective screening methods, among which heel quantitative ultrasound appears to be the most widely used in resource limited countries such as South Africa.

Quantitative Ultrasound (QUS) in the Management of Osteoporosis and Assessment of Fracture Risk

The use of quantitative ultrasound (QUS) for a variety of skeletal sites, associated with the absence of technology-specific guidelines, has created uncertainty with respect to the application of QUS results to the management of individual patients in clinical practice. However, when prospectively validated (this is not the case for all QUS devices and skeletal sites), QUS is a proven, low-cost, and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurements of bone mineral density (BMD) for the assessment of fracture risk. Indeed, the clinical use of QUS to identify subjects at low or high risk of osteoporotic fracture should be considered when central DXA is unavailable. Furthermore, the use of QUS in conjunction with clinical risk factors (CRF),allows for the identification of subjects who have a low and high probability of osteoporotic fracture. Device- and parameter-specific thresholds should be developed and cross-validated to confirm the concurrent use of QUS and CRF for the institution of pharmacological therapy and monitoring therapy.

Discriminative ability of calcaneal quantitative ultrasound compared with dual-energy X-ray absorptiometry in men with hip or distal forearm fractures

Objectives

The aim of this case–control study was to compare the discriminatory ability of bone mineral density (BMD) measurements and calcaneal quantitative ultrasound (QUS) parameters for fractures and to determine fracture thresholds for each variable in men with hip or distal forearm fractures.

Patients and methods

A total of 20 men with hip and 18 men with distal forearm fractures and 38 age-matched controls were included in this study. Dual-energy X-ray absorptiometry (DXA) BMD (spine and hip) and calcaneal QUS measurements were made. Area under the curves (AUCs) were calculated to assess fracture discriminatory power of DXA and QUS variables.

Results

Quantitative Ultrasound Index (QUI) T-score and Speed of Sound (SOS) were found to be the best parameters for the identification of hip and distal forearm fractures, respectively, with AUCs greater than those of DXA BMD and other QUS parameters. While a QUI T-score of ≤−1.18 could identify and rule out hip fracture cases with approximately 80% sensitivity and specificity, a SOS value of ≤1529.75 reached to almost 90% for ruling in and out distal forearm fractures.

Conclusion

The discriminatory performance of calcaneal QUS variables between fractured and non-fractured men was as good as those of the DXA BMD and even better. Since men appear to sustain fractures at closer QUS variable levels than those of the DXA BMD regardless of the fracture type, it may be speculated that calcaneal QUS may be more helpful in predicting the risk of fractures when BMD alone does not demonstrate impaired bones.

Level of Evidence: Level III, Study of Diagnostic Test

Prevalence of osteoporosis in the Italian population and main risk factors: results of BoneTour Campaign

BACKGROUND

BoneTour is a campaign conducted throughout the Italian territory for the assessment of Italian people bone status and for the prevention of osteoporosis.

METHODS

A total of 7305 sequential subjects of both sexes were screened, collecting clinical data through the FRAX™ questionnaire, and measuring heel bone stiffness by Quantitative Ultrasonography (QUS). The 10-year risk for hip and major osteoporotic fractures was calculated taking into account personal or family history of fragility fracture, smoking, alcohol abuse, rheumatoid arthritis, prolonged steroids assumption. Additional risk factors were evaluated, including early menopause, poor sunlight exposure, low dietary calcium intake, physical inactivity, number of pregnancies, months of lactation, tobacco cigarettes smoked per year, specific causes of secondary osteoporosis. Through a correlation study, the influence of each factor on the development of osteoporosis was analyzed.

RESULTS

As many as 18 % of women suffer from osteoporosis, as defined by QUS T-score. The calculation of FRAX™ confirmed the weight of the already known risk factors. The correlation study revealed the significance of some additional factors, such as hyperthyroidism, nephrolithiasis, Crohn disease, ulcerative colitis, celiac disease, poor sun exposure, and oophorectomy before age 50.

CONCLUSIONS

The high prevalence of secondary osteoporosis in the Italian population clearly indicates the importance of additional risk factors not yet included in the FRAX™ algorithm, for which preventive measures should be considered. Screening campaigns may allow both early diagnosis and access to treatment.

Positive Association Between Adipose Tissue and Bone Stiffness

Obesity is often considered to have a protective effect against osteoporosis. On the other hand, several recent studies suggest that adipose tissue may have detrimental effects on bone quality. We therefore aimed to investigate the associations between body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) or abdominal subcutaneous adipose tissue (SAT), and bone stiffness. The study involved 2685 German adults aged 20-79 years, who participated in either the second follow-up of the population-based Study of Health in Pomerania (SHIP-2) or the baseline examination of the SHIP-Trend cohort. VAT and abdominal SAT were quantified by magnetic resonance imaging. Bone stiffness was assessed by quantitative ultrasound (QUS) at the heel (Achilles InSight, GE Healthcare). The individual risk for osteoporotic fractures was determined based on the QUS-derived stiffness index and classified in low, medium, and high risk. Linear regression models, adjusted for sex, age, physical activity, smoking status, risky alcohol consumption, diabetes, and height (in models with VAT or abdominal SAT as exposure), revealed positive associations between BMI, WC, VAT or abdominal SAT, and the QUS variables broadband-ultrasound attenuation or stiffness index. Moreover, BMI was positively associated with speed of sound. Our study shows that all anthropometric measures including BMI and, WC as well as abdominal fat volume are positively associated with bone stiffness in the general population. As potential predictors of bone stiffness, VAT and abdominal SAT are not superior to easily available measures like BMI or WC.

The prevention of fragility fractures in diabetic patients

Patients with diabetes mellitus (DM) are at greater risk of fractures mostly due to not only extraskeletal factors, such as propensity to falls, but also to bone quality alteration, which reduces bone strength. In people with DM, insulin deficit and hyperglycemia seem to play a role in determining bone formation alteration by AGE accumulation which directly influences osteoblast activity. Although there are conflicting data in the literature, adequate glycemic control with hypoglycemic treatment may be an important element in preventing bone tissue alterations in both type 1 and type 2 DM. Diabetes status is a predictive of future hip and major osteoporosis fractures independently of BMD and FRAX probability. Attention should be paid to the use of thiazolidinediones, especially in older women, because the direct negative effect on bone could exceed the positive effect of glycemic control. Systematic screening for complications and fall prevention efforts, along with calcium and vitamin D repletion and adequate physical activity, represents the mainstay of fracture prevention in DM patients. All anticatabolic drugs (raloxifene, bisphosphonates, denosumab) seem to be effective in DM patients. On the basis of pathophysiological evidence that suggests low bone formation in DM patients, osteoanabolic therapies such as teriparatide might represent an important therapeutic option for DM patients with severe osteoporosis and/or multiple fractures. The search for better methods for the identification of fragility fracture risk in the growing population of adult and elderly subjects with DM might be considered a clinical priority which could improve the prevention of fracture in DM patients.

Quantitative ultrasound measurements of the calcaneus and hand phalanges in elderly Spanish men: relationship with peripheral bone mineral density of the hand phalanges

OBJECTIVES

The aims of this pilot study were to describe quantitative ultrasound (US) measurements and peripheral bone mineral density (BMD) of the hand phalanges on dual-energy x-ray absorptiometry and to examine the correlations between them in elderly Spanish men.

METHODS

We studied 199 healthy men (mean age ± SD, 73.31 ± 5.10 years). The participants were not taking any medications, and they reported no diseases, including diseases that are associated with abnormalities in mineral metabolism. Phalangeal and calcaneal quantitative US measurements and phalangeal BMD measurements were performed in all participants.

RESULTS

A bivariate correlation analysis showed no association between quantitative US assessments at the phalanges or the calcaneus (P = .409). After adjustment for potential confounders, the correlation between phalangeal BMD and phalangeal quantitative US measurements was r = 0.417 (P < .0001), and the correlation for calcaneal quantitative US was r = 0.26 (P = .001). Further adjustment by percentage of body fat increased quantitative US correlations with phalangeal BMD: r = 0.450 (P < .0001) at the phalanges; r = 0.291 (P = .001) at the calcaneus.

CONCLUSIONS

There is a small correlation between quantitative US measurements at the calcaneus and phalangeal BMD that increases to a moderate level with quantitative US measurements at the phalanges in elderly Spanish men.

Low Testosterone Levels Are Associated With Poor Peripheral Bone Mineral Density and Quantitative Bone Ultrasound at Phalanges and Calcaneus in Healthy Elderly Men

Variations in sex hormones influence bone health in men. Aging in men is associated with a decrease in testosterone (T) levels. We examined the relationship between T levels and changes in bone health status as measured by quantitative ultrasound (QUS) at the phalanges and the os calcis and by peripheral bone mineral density (pBMD) at the phalanges in healthy elderly Spanish men. We examined 162 men aged 65–88 years and assessed total serum T concentrations. Total serum T < 300 ng/dL was used as the threshold for biochemical T deficiency. The sample was divided into low ( n = 66) or normal ( n = 96) T levels; both groups were matched for age, weight, height, and body mass index ( p > .05 for all the comparisons). All measured bone parameters were higher in the normal serum T group ( p < .05). Multiple regression analysis revealed that serum T was an independent predictor of both QUS at the calcaneus and phalangeal pBMD. Our data indicate that T is an independent determinant of QUS at the os calcis and pBMD at the phalanges in elderly Spanish men.

Genetic determinants of heel bone properties: genome-wide association meta-analysis and replication in the GEFOS/GENOMOS consortium

Quantitative ultrasound of the heel captures heel bone properties that independently predict fracture risk and, with bone mineral density (BMD) assessed by X-ray (DXA), may be convenient alternatives for evaluating osteoporosis and fracture risk. We performed a meta-analysis of genome-wide association (GWA) studies to assess the genetic determinants of heel broadband ultrasound attenuation (BUA; n = 14 260), velocity of sound (VOS; n = 15 514) and BMD (n = 4566) in 13 discovery cohorts. Independent replication involved seven cohorts with GWA data (in silico n = 11 452) and new genotyping in 15 cohorts (de novo n = 24 902). In combined random effects, meta-analysis of the discovery and replication cohorts, nine single nucleotide polymorphisms (SNPs) had genome-wide significant (P < 5 × 10(-8)) associations with heel bone properties. Alongside SNPs within or near previously identified osteoporosis susceptibility genes including ESR1 (6q25.1: rs4869739, rs3020331, rs2982552), SPTBN1 (2p16.2: rs11898505), RSPO3 (6q22.33: rs7741021), WNT16 (7q31.31: rs2908007), DKK1 (10q21.1: rs7902708) and GPATCH1 (19q13.11: rs10416265), we identified a new locus on chromosome 11q14.2 (rs597319 close to TMEM135, a gene recently linked to osteoblastogenesis and longevity) significantly associated with both BUA and VOS (P < 8.23 × 10(-14)). In meta-analyses involving 25 cohorts with up to 14 985 fracture cases, six of 10 SNPs associated with heel bone properties at P < 5 × 10(-6) also had the expected direction of association with any fracture (P < 0.05), including three SNPs with P < 0.005: 6q22.33 (rs7741021), 7q31.31 (rs2908007) and 10q21.1 (rs7902708). In conclusion, this GWA study reveals the effect of several genes common to central DXA-derived BMD and heel ultrasound/DXA measures and points to a new genetic locus with potential implications for better understanding of osteoporosis pathophysiology.

Relationship between quantitative ultrasound parameters at the calcaneus and health-related quality of life in postmenopausal Italian women: the FEDRO study

Reduced bone mineral density has been reported to adversely affect health-related quality of life (HRQoL) in postmenopausal women without vertebral fracture. To date, no data exist in the literature about any possible influences of quantitative ultrasonographic (QUS) parameters on HRQoL. This study aimed to assess whether QUS parameters at the calcaneus may be associated with HRQoL. In 1,812 ambulatory postmenopausal women aged 60 years or over, we measured HRQoL by the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-41) and stiffness index using QUS at the calcaneus. By grouping the 1,812 women on the basis of stiffness index, a highly significant (p < 0.001) difference was found for both total QUALEFFO and five domains of the QUALEFFO, whereas for the Pain and Mental Function domains the significance was modest. Stiffness was inversely associated (p < 0.01) with total QUALEFFO and with all QUALEFFO domains. In stepwise multiple logistic regression analysis stiffness values were negatively associated with both QUALEFFO total score and all domains of the QUALEFFO-41. The presence of concomitant diseases was associated with a worsening of HRQoL in all domains of the QUALEFFO, whereas age was associated with the three domains of physical function but not with the Pain and Mental Function domains. Our study suggests that in postmenopausal women there is a close relationship between bone status measured by QUS at the calcaneus and quality of life assessed by the QUALEFFO. Therefore, QUS at the calcaneus may have a role in early strategies to prevent HRQoL impairment and osteoporosis exacerbation.

Calcaneal quantitative ultrasound as a determinant of bone health status: what properties of bone does it reflect?

Quantitative ultrasound (QUS) has emerged as a convenient and popular screening tool for osteoporosis. This review aimed to provide basic information on the principle of QUS measurement and discuss the properties of bone reflected by QUS indices. QUS employed high frequency sound waves generated by the device to determine bone health status in humans. In vitro studies showed that QUS indices were significantly associated with bone mineral density (BMD), bone microarchitecture and mechanical parameters. In humans, QUS indices were found to be associated with BMD as well. In addition, QUS could discriminate subjects with and without fracture history and predict risk for future fracture. In conclusion, QUS is able to reflect bone quality and should be used in the screening of osteoporosis, especially in developing countries where dual-X-ray absorptiometry devices are less accessible to the general population.

A screening model for low bone mass in elderly Japanese men using quantitative ultrasound measurements: Fujiwara-Kyo Study

Screening for low bone mass is important to prevent fragility fractures in men as well as women, although men show a much lower prevalence of osteoporosis than women. The purpose of this study was to establish a screening model for low bone mineral density (BMD) using a quantitative ultrasound parameter and easily obtained objective indices for elderly Japanese men. We examined 1633 men (65-84 yr old) who were subjects of the Fujiwara-Kyo Study. Speed of sound (SOS) at the calcaneus was determined, and BMD was measured by dual-energy X-ray absorptiometry at the lumbar spine (LS), total hip (TH), and femoral neck (FN). Low BMD was defined as >1 standard deviation below the young adult mean, in accordance with World Health Organization criteria. We performed receiver operating characteristic (ROC) analysis to identify a better screening model incorporating SOS and determined the optimal cutoff value using Youden index. Prevalences of low BMD at the 3 skeletal sites were 27.8% (LS), 33.5% (TH), 48.6% (FN), and 43.3% at either LS or TH. The greatest area under the ROC curve (0.806, 95% confidence interval: 0.785-0.828) and smallest Akaike's information criterion were obtained in the multivariate model incorporating SOS, age, height, and weight for predicting low BMD at all skeletal sites. This model predicted low BMD at TH with the sensitivity of 0.726 and specificity of 0.739, whereas a similar model predicted low BMD at LS with much lower validity. We conclude that the multivariate model for TH could be used to screen for low BMD in elderly Japanese men.

The association of body composition and sex hormones with quantitative ultrasound parameters at the calcaneus and phalanxes in elderly women

We investigated the associations of body composition and sex hormones with quantitative ultrasound (QUS) parameters carried out at different skeletal sites. In 897 postmenopausal women (64.1 ± 6.6 years) we measured QUS at the calcaneus (stiffness) by Achilles-GE and at phalanxes (amplitude-dependent speed of sound [AD-SOS], bone transmission time [BTT], and ultrasound bone profile index [UBPI]) by Bone Profiler-IGEA. In all subjects we measured fat mass (FM), lean mass (LM), android fat, and gynoid fat by DXA. In all subjects we also assessed serum testosterone (T), estradiol (E(2)), sex-hormone binding globulin, free estrogen index (FEI), free androgen index, 25-hydroxyvitamin D (25OHD), bone alkaline phosphatase (B-ALP), and type I collagen β carboxy telopeptide. Both E(2) and FEI showed weak but significant correlations with stiffness and QUS parameters at phalanxes. No significant relationships were found between T and QUS. BMI and LM were positively correlated with stiffness (r = 0.14 and r = 0.17, respectively), whereas BMI and FM showed negative correlations with AD-SOS, BTT, and UBPI. 25OHD showed positive relationships with stiffness and QUS at phalanxes. In multivariate models LM and age were associated with stiffness whereas E(2) and age were significant predictors of BTT. AD-SOS was negatively associated with FM, B-ALP, and age but positively with E(2) and 25OHD. In postmenopausal women QUS parameters at the calcaneus and at phalanxes are significantly, but diversely, associated with body composition, sex hormones, 25OHD, and bone turnover markers.

Influence of bone remodelling rate on quantitative ultrasound parameters at the calcaneus and DXA BMDa of the hip and spine in middle-aged and elderly European men: the European Male Ageing Study (EMAS)

OBJECTIVE

To assess the influence of sex hormones on markers of bone turnover and to explore the association between these markers and bone health in middle-aged and elderly European men.

DESIGN

A cross-sectional population-based survey.

METHODS

Men aged 40-79 years were recruited from population registers in eight European centres. Subjects completed a postal questionnaire which included questions concerning lifestyle and were invited to undergo quantitative ultrasound (QUS) of the calcaneus and to provide a fasting blood sample from which the bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β C-terminal cross-linked telopeptide (β-cTX)), total testosterone, total oestradiol (E(2)), sex hormone-binding globulin (SHBG) and insulin-like growth factor 1 (IGF1) were measured. Dual-energy X-ray absorptiometry (DXA) of the hip and lumbar spine was performed in two centres.

RESULTS

A total of 3120, mean age 59.9 years (s.d.=11.0) were included. After adjustment for centre, age, height, weight, lifestyle factors, season and other hormones, total and free E(2) were negatively associated with β-cTX but not P1NP while SHBG, IGF1 and parathyroid hormone (PTH) were positively associated with both β-cTX and P1NP. Total or free testosterone was not independently associated with either bone marker. After the same adjustments, higher levels of both bone markers were significantly associated with lower QUS parameters and lower DXA-assessed bone density at the total hip and lumbar spine.

CONCLUSIONS

E(2), SHBG, IGF1 and PTH contribute significantly to the regulation/rate of bone turnover in middle-aged and older European men. Higher rates of bone remodelling are negatively associated with male bone health.

Assessment of bone status in inhaled corticosteroid user asthmatic patients with an ultrasound measurement method

BACKGROUND

The effect of inhaled corticosteroid (ICS) on the bone status of asthmatic patients is still uncertain, because it can differ by race and because there have been few cases in Japan. In this study, the bone status of ICS users with asthma was evaluated in an actual clinical setting in Japan.

METHODS

In 7 participating hospitals, ICS users with asthma and control subjects were age- and gender-matched and recruited into this study. To assess bone status, ultrasound measurements of each individual's calcaneus were made using an AOS-100. The ratio of the osteo sono-assessment index (OSI) to the average OSI corrected for age and gender was denoted as %OSI and used for quantitative assessment. The second %OSI measurement was performed 6 months after the first %OSI one. During the study period, individual treatment remained unchanged.

RESULTS

There were no significant differences in the 1st and 2nd %OSI between the ICS users and control subjects. However, the 2nd %OSI significantly decreased compared with 1st %OSI in female ICS users, although there were no significant changes in the male and female control subjects and male ICS users.

CONCLUSIONS

The 6 month management of asthma in the actual clinical setting, including regular ICS use, might have a harmful influence on the bone status of female asthmatic patients. It may be necessary to manage and treat female patients for potent corticosteroid-induced osteoporosis, although further analyses of bone status in asthma patient ICS users will be required.

Fracture status in men assessed by quantitative ultrasound measurements at the calcaneus

OBJECTIVES

The aim of the study was to assess fracture status in men by quantitative ultrasound measurements at the calcaneus. The diagnostic accuracy of quantitative ultrasound measurements was evaluated at baseline and follow-up.

METHODS

We observed 165 men (baseline age ± SD, 59.84 ± 10.6 years) recruited from an outpatient osteoporosis clinic. The mean follow-up duration was approximately 101.3 ± 35 months. There was no difference in either age or body mass index at baseline between the patients with a fracture history (n = 30) and the others (n = 135). The following fractures were identified at baseline: ankle, 15; wrist, 10; rib, 9; foot, 5; and hip, 1. The speed of sound (meters per second), broadband ultrasound attenuation (decibels per megahertz), and stiffness index (percent) were measured with a quantitative ultrasound device. The date of fracture occurrence at follow-up was defined as the final point.

RESULTS

In the patients with a fracture history, the ultrasound variables were significantly lower than those in the rest of the group (P < .05). During the follow-up period, fractures occurred in 21 patients (wrist, 11; ankle, 5; rib, 3; hip, 1; and humerus, 1), and the ultrasound outcomes were nonsignificantly lower in the fractured men. The risk of fracture was estimated by the Cox regression analysis. A prior fracture was the only factor that significantly (4 times) increased the risk of a subsequent fracture (hazard ratio, 4.21; 95% confidence interval, 1.81-9.86; P < .001).

CONCLUSIONS

Calcaneus ultrasound measurements can distinguish between patients with fractures and those without. In follow-up, ultrasound measurements did not indicate an increased fracture risk; a prior osteoporotic fracture was the major prognostic factor.

Development of a parametric finite element model of the proximal femur using statistical shape and density modelling

Skeletal fractures associated with bone mass loss are a major clinical problem and economic burden, and lead to significant morbidity and mortality in the ageing population. Clinical image-based measures of bone mass show only moderate correlative strength with bone strength. However, engineering models derived from clinical image data predict bone strength with significantly greater accuracy. Currently, image-based finite element (FE) models are time consuming to construct and are non-parametric. The goal of this study was to develop a parametric proximal femur FE model based on a statistical shape and density model (SSDM) derived from clinical image data. A small number of independent SSDM parameters described the shape and bone density distribution of a set of cadaver femurs and captured the variability affecting proximal femur FE strength predictions. Finally, a three-dimensional FE model of an 'unknown' femur was reconstructed from the SSDM with an average spatial error of 0.016 mm and an average bone density error of 0.037 g/cm(3).

Association between alcohol consumption and bone strength in Korean adults: the Korean Genomic Rural Cohort Study

Previous studies have reported an inconsistent relationship between alcohol consumption and bone health. A growing body of research has shown that chronic alcoholism leads to osteopenia and increased incidence of skeletal fractures, but some studies have concluded that alcohol consumption may be associated with higher bone mineral density in elderly populations. However, most studies showing a significant relationship between alcohol consumption and bone status have been in Western countries; and subjects have usually been postmenopausal women. The purpose of the present study was to investigate the association of alcohol consumption with bone strength in Korean adults. Data were from the Korean Genomic Rural Cohort Study, which is an ongoing population-based study of adults aged 40 to 70 years from 5 regions. A total of 7713 participants (3368 men, 4345 women) were surveyed about their annual consumption of alcohol such as soju, beer, makkolli, wine, and whisky. Bone strength was measured by stiffness index using the calcaneal quantitative ultrasound method. Overall, the annual age-specific decrease rate in the stiffness index of women was 2.7 times higher than that of men (0.463% for women, 0.169% for men).After adjustment for eligible covariates, the association between alcohol consumption and risk of reduced bone strength showed a J-shaped curve for both men and women. Compared with nondrinkers, the relative risk of reduced bone strength was 0.52 (95% confidence interval, 0.33-0.83) in men who drank 4 to 5 cups of soju for an amount of 29.626 to 49.375 g of alcohol per day and 0.61 (95% confidence interval, 0.38-0.86) in men who drank 6 to 7 cups of soju for an amount of 49.376 to 69.125 g of alcohol per day. We found no significant relationship between alcohol consumption and bone strength in any other group of men. For women, results suggested that the risk of reduced bone strength was lower in the moderate-consumption group; but no significant relationship was found between alcohol consumption at any level and bone strength. Among Korean adults, alcohol consumption has a J-shaped relationship with risk of reduced bone strength.

Physical activity is the strongest predictor of calcaneal peak bone mass in young Swedish men

SUMMARY

In a highly representative sample of young adult Swedish men (n = 2,384), we demonstrate that physical activity during childhood and adolescence was the strongest predictor of calcaneal bone mineral density (BMD), and that peak bone mass was reached at this site at the age of 18 years.

INTRODUCTION

The purpose of the present study was to determine if physical activity during growth is associated with peak calcaneal BMD in a large, highly representative cohort of young Swedish men.

METHODS

In this study, 2,384 men, 18.3 +/- 0.3 (mean +/- SD) years old, were included from a population attending the mandatory tests for selection to compulsory military service in Sweden. BMD (g/cm(2)) of the calcaneus was measured using dual-energy X-ray absorptiometry. Training habits were investigated using a standardized questionnaire.

RESULTS

Regression analysis (with age, height, weight, smoking, and calcium intake as covariates) demonstrated that history of regular physical activity was the strongest predictor and could explain 10.1% of the variation in BMD (standardized beta = 0.31, p < 0.001). A regression model with quadratic age effect revealed maximum BMD at 18.4 years.

CONCLUSIONS

We found that history of physical activity during growth was the strongest predictor of peak calcaneal BMD in young men.

Sex steroids and bone turnover markers in men with symptomatic vertebral fractures

Sex steroids play an important role in the maintenance of bone density in men and women, but the circulating, biologically active unbound fraction is influenced by the concentration of sex hormone binding globulin (SHBG). SHBG increases with advancing age in men and leads to a reduction in serum free testosterone and oestradiol, which may then affect bone turnover, bone mineral density (BMD) and the risk of fractures. We have therefore measured total and unbound sex steroids, SHBG, bone turnover markers and BMD in 57 men with symptomatic low trauma vertebral fractures and 57 age-matched male control subjects. Fasting blood and urine samples were collected from all subjects, who also underwent BMD measurement of the lumbar spine and hip. Serum testosterone, oestradiol, SHBG, bone specific alkaline phosphatase (bone ALP) and urine free deoxypyridinoline/creatinine ratio (fDPD/Cr) were measured. Free sex steroid concentrations were calculated using their ratio with SHBG and albumin and bioavailable testosterone was measured using radioimmunoassay. The two groups were then compared and regression models developed to determine the best predictors of BMD and fracture. Men with vertebral fractures had significantly lower weight and BMD at all sites than control subjects (p<0.0001). Serum total testosterone and oestradiol did not differ between the two groups, but calculated free androgen and free oestradiol indices were lower in the fracture group than the control subjects (p=0.04), due to higher SHBG (46.6 versus 36.1 nmol/L: p=0.005). The men with vertebral fractures had significantly higher mean bone ALP (15.8 versus 11.8 microg/L: p=0.002) and fDPD/Cr (5.5 versus 4.0 nmol/mmol: p=0.03). Stepwise multiple regression analysis in both fracture and control groups found body weight to be the best predictor of BMD. In the fracture group weight predicted between 19.7 and 30.7% of the variance in BMD and in control subjects this was between 12.3 and 13.2%. SHBG contributed to the model for hip BMD in the fracture group alone, so that weight and SHBG together accounted for 32 to 42.9% of the variance. A model combining BMD at the spine, total femur and femoral neck with height loss best predicted fracture. In conclusion, men with symptomatic vertebral fractures have higher SHBG and lower calculated free sex steroid indices, increased bone turnover and lower BMD. Whilst body weight was the best predictor of BMD, symptomatic vertebral fracture was best predicted by BMD and height loss.

Bone stiffness in men with type 2 diabetes mellitus

Osteoporosis in elderly men as well as women is increasingly recognized, and patients with type 2 diabetes mellitus have higher risk of fracture than nondiabetic subjects. The aim of the present study was to investigate the relationship between bone stiffness and serum testosterone concentration as well as other variables in men with type 2 diabetes mellitus. The relationships between bone stiffness and serum bioavailable testosterone concentrations as well as other variables including age, duration of diabetes, glycemic control (hemoglobin A(1c)), or body mass index were evaluated in 294 men with type 2 diabetes mellitus. An inverse correlation was found between stiffness index and age. A positive correlation was found between stiffness index and serum bioavailable testosterone concentration (r = 0.231, P = .0005). Stiffness index was significantly less in current smokers (81.6 +/- 17.7) than in past smokers (86.6 +/- 17.8, P = .0396) or nonsmokers (87.7 +/- 15.2, P = .0426). Multiple regression analysis demonstrated that serum bioavailable testosterone concentration (beta = .271, P = .0006) and smoking status (beta = -0.147, P = .0408) were independent determinants of stiffness index. In conclusion, bone stiffness was associated with serum bioavailable testosterone concentration but not associated with hemoglobin A(1c) or duration of diabetes in men with type 2 diabetes mellitus.

Osteoporosis risk in frail older adults in assisted living

OBJECTIVES

To compare osteoporosis risk in residents of assisted living (AL) with that of age- and sex-matched community-dwelling adults.

DESIGN

Cross-sectional.

SETTING

Community and AL facilities in Connecticut.

PARTICIPANTS

One hundred seven individuals (77 control, 37 AL).

ASSESSMENTS

Fracture and osteoporosis evaluation history, qualitative heel ultrasound (QUS), 25-hydroxyvitamin D (25OHD), parathyroid hormone (PTH), and physical function measures, including walking speed, chair rise time, 6-minute walk, Berg Balance Scale, Get Up and Go, and handgrip strength.

RESULTS

Participants' mean age was 82.7+/-5.7. There were no group differences in reported fracture, diagnosis of osteoporosis, or previous bone mineral density (BMD) assessment. QUS T-scores were -1.0+/-1.5 for community living and -1.9+/-1.3 for AL (P=.002), 25OHD levels were 113.0+/-40.1 nnmol/L for community living and 81.8+/-36.9 for AL (P<.001), and PTH levels were 50.8+/-29.8 pg/mL for community living and 58.8+/-32.8 pg/mL for AL (P=.22). Physical performance was more impaired in AL (P<.05), except for single leg stance (P=.16). In linear regression analysis, age, sex, and site of residence were significant predictors of heel T-score, explaining 53.7% of the variance.

CONCLUSION

Residents of AL did not report less fracture or osteoporosis than those from the community, but risk factors measured directly were significantly different, including lower BMD and 25OHD and more impairment in measures of physical function. These data suggest that residents of AL are at greater risk for osteoporotic fracture and that measures to diminish risk (optimizing vitamin D status, implementing fall prevention strategies, incorporating exercise to improve physical performance) should be considered and studied for benefit.

Bone mass and architecture determination: state of the art

Bone fracture occurs when the bone strength (i.e. the ability of the bone to resist a force) is less than the force applied to the bone. In the elderly, falls represent the more severe forces applied to bone. Bone density is a good marker of bone strength, and has been used widely in this respect. Nevertheless, many aspects of bone strength cannot be explained by bone density alone. For this reason there has been increasing interest in studying architectural parameters of bone, beyond bone density, which may affect bone strength. Macro-architectural parameters include e.g. bone size and geometry assessed with techniques such as radiography, dual-energy x-ray absorptiometry (DXA), peripheral quantitative computed tomography (QCT), computed tomography (CT) and magnetic resonance imaging (MRI). Micro-architectural parameters include fine cortical and trabecular structural detail which can be evaluated using high-resolution imaging techniques such as multidetector CT, MRI, and high-resolution peripheral QCT. These techniques are providing a great deal of new information on the physiological architectural responses of bone to aging, weightlessness, and treatment. This will ultimately lead to the prediction of fracture risk being improved through a combined assessment of bone density and architectural parameters.

Nutrient intake and bone health status of Korean male college students as related to smoking situations

The purpose of this study was to compare the dietary habits, nutrient intake, bone mineral density (BMD) and bone metabolism in Korean male collegians as related to smoking situation. One hundred sixty one young adult males at the age of 20-26 participated in this study. The subjects were divided into four groups: non smoker (n=42), light smoker (n=34), moderate smoker (n=49) and heavy smoker (n=36). The anthropometric characteristics, smoking situations, dietary habits and nutrient intakes were observed. Bone status of the calcaneus was measured by using quantitative ultrasound (QUS). Bone metabolism markers including serum alkaline phosphatase activity (ALP) and N-mid osteocalcin (OC) were analyzed. There were no significant differences in height, weight, BMI, energy and calcium intake among the four groups. Iron intake of moderate and heavy smoker was significantly lower than that of light smoker. Heavy smokers consumed significantly lower vitamin C than moderate smokers, and their coffee consumption and lifetime alcohol consumption were significantly highest among the 4 groups. QUS parameters and serum ALP were not significantly different among the four groups. Serum OC levels were significantly lower in heavy and non smoker group compared to the moderate smoker group. In conclusion, heavy smokers in young male collegians had undesirable lifestyle and dietary habits, like as high consumption of coffee and alcohol, and low intake of Fe and vitamin C. Although, there was no significant difference in their current bone status from the other groups, these undesirable factors with heavy smoking may affect their bone health in the long term.

Quantitative ultrasound in the management of osteoporosis: the 2007 ISCD Official Positions

Dual-energy X-ray absorptiometry (DXA) is commonly used in the care of patients for diagnostic classification of osteoporosis, low bone mass (osteopenia), or normal bone density; assessment of fracture risk; and monitoring changes in bone density over time. The development of other technologies for the evaluation of skeletal health has been associated with uncertainties regarding their applications in clinical practice. Quantitative ultrasound (QUS), a technology for measuring properties of bone at peripheral skeletal sites, is more portable and less expensive than DXA, without the use of ionizing radiation. The proliferation of QUS devices that are technologically diverse, measuring and reporting variable bone parameters in different ways, examining different skeletal sites, and having differing levels of validating data for association with DXA-measured bone density and fracture risk, has created many challenges in applying QUS for use in clinical practice. The International Society for Clinical Densitometry (ISCD) 2007 Position Development Conference (PDC) addressed clinical applications of QUS for fracture risk assessment, diagnosis of osteoporosis, treatment initiation, monitoring of treatment, and quality assurance/quality control. The ISCD Official Positions on QUS resulting from this PDC, the rationale for their establishment, and recommendations for further study are presented here.