Recalculation of the NHANES database SD improves T-score agreement and reduces osteoporosis prevalence

Physical activity attenuates the excess mortality risk from prolonged sitting time among adults with osteoporosis or osteopenia

PURPOSE

Osteoporosis is a common generalized skeletal disorder characterized by compromised bone strength predisposing a person to an increased risk of fracture. This study aims to crystallize associations of physical activity (PA) and sedentary behaviour with the survival of adults with osteoporosis or osteopenia.

METHODS

A total of 3103 participants aged 50 years or older from the National Health and Nutrition Examination Survey (NHANES) were included in the study. All participants were diagnosed with osteopenia or osteoporosis. Multivariable Cox proportional hazards regression models were used to assess the association of PA and sedentary behaviour with overall mortality, cancer-related mortality, and cardiovascular disease (CVD)-related mortality.

RESULTS

During 21349 person-years of follow-up, 675 deaths were documented. Highly active participants had a lower risk of all-cause (hazard ratios [HR] = 0.61; 95% confidence interval [CI], 0.42-0.87; P for trend = 0.004), cancer-specific (HR = 0.64; 95%CI, 0.35-1.17; P for trend = 0.132), CVD-specific (HR = 0.75; 95%CI, 0.45-1.25; P for trend = 0.452), and other (HR, 0.51; 95%CI, 0.29-0.88; P for trend = 0.005) mortality than inactive participants. And sitting time was not associated with mortality among physically active participants; while among those who were insufficiently active or inactive, longer sitting time was associated with increased risks of all-cause (HR per 1-h increase = 1.05; 95% CI, 1.01-1.09), cancer-specific (HR per 1 h increase = 0.98; 95% CI, 0.90-1.07), CVD-specific (HR per 1-h increase = 1.11; 95% CI = 1.04-1.18), and other (HR per 1-h increase = 1.05; 95% CI, 0.98-1.13) mortality in a dose-response manner.

CONCLUSIONS

PA can attenuate the excess mortality risk from prolonged sitting for individuals with osteoporosis and/or osteopenia. The combination of prolonged sedentary behaviour with inactive (participants without any PA during a week) PA was associated with an increased risk of mortality. The all-cause mortality risk of individuals who engage in less than 150 min/wk PA and sit more than 8 h/d is 2.02 (95% CI, 1.37-2.99) times higher than that of individuals who engage in more than 150 min/wk PA and sit less than 4 h/d.

A new FRAX model for Brazil

Fracture probabilities derived from the original FRAX model for Brazil were compared to those from an updated model based on more recent regional estimates of the incidence of hip fracture. Fracture probabilities were consistently lower in the updated FRAX model. Despite large differences between models, differences in the rank order of fracture probabilities were minimal.

OBJECTIVE

Recent epidemiological data indicate that the risk of hip fracture in Brazil is lower than that used to create the original FRAX model. This paper describes the epidemiology of hip fracture in Brazil and the synthesis of an updated FRAX model with the aim of comparing this new model with the original model.

METHODS

Hip fracture rates from three cities in three regions were combined, weighted by the population of each region. For other major fractures, incidence rates for Brazil were estimated using Swedish ratios for hip to other major osteoporotic fracture (humerus, forearm or clinical vertebral fractures). Mortality estimates were taken from the UN.

RESULTS

Compared to the original FRAX model, the updated model gave lower 10-year fracture probabilities in men and women at all ages. Notwithstanding, there was a very close correlation in fracture probabilities between the original and updated models (r > 0.99) so that the revisions had little impact on the rank order of risk.

CONCLUSION

The disparities between the original and updated FRAX models indicate the importance of updating country-specific FRAX models with the advent of significant changes in fracture epidemiology.

Oral health outcomes in an HIV cohort with comorbidities- implementation roadmap for a longitudinal prospective observational study

BACKGROUND

Long-term antiretroviral therapy (ART) perpetually suppresses HIV load and has dramatically altered the prognosis of HIV infection, such that HIV is now regarded as a chronic disease. Side effects of ART in Patients With HIV (PWH), has introduced new challenges including "metabolic" (systemic) and oral complications. Furthermore, inflammation persists despite great viral load suppression and normal levels of CD4+ cell count. The impact of ART on the spectrum of oral diseases among PWH is often overlooked relative to other systemic complications. There is paucity of data on oral complications associated with ART use in PWH. This is in part due to limited prospective longitudinal studies designed to better understand the range of oral abnormalities observed in PWH on ART.

METHODS

We describe here the study design, including processes associated with subject recruitment and retention, study visit planning, oral health assessments, bio-specimen collection and preprocessing procedures, and data management and statistical plan.

DISCUSSION

We present a procedural roadmap that could be modelled to assess the extent and progression of oral diseases associated with ART in PWH. We also highlight the rigors and challenges associated with our ongoing participant recruitment and retention. A rigorous prospective longitudinal study requires proper planning and execution. A great benefit is that large data sets are collected and biospecimen repository can be used to answer more questions in future studies including genetic, microbiome and metabolome-based studies.

TRIAL REGISTRATION

National Institute of Health Clinical Trials Registration (NCT) #: NCT04645693.

Oral Health Outcomes In An HIV Cohort With Comorbidities- Implementation Roadmap For A Longitudinal Prospective Observational Study

Long-term antiretroviral therapy (ART) perpetually suppresses HIV load and has dramatically altered the prognosis of HIV infection, such that HIV is now regarded as a chronic disease. Side effects of ART in Patients With HIV (PWH), has introduced new challenges including "metabolic" (systemic) and oral complications. Furthermore, inflammation persists despite great viral load suppression and normal levels of CD4+ cell count. The impact of ART on the spectrum of oral diseases among PWH is often overlooked relative to other systemic complications. There is paucity of data on oral complications associated with ART use in PWH. This is in part due to limited prospective longitudinal studies designed to better understand the range of oral abnormalities observed in PWH on ART. Our group designed and implemented a prospective observational longitudinal study to address this gap. We present a procedural roadmap that could be modelled to assess the extent and progression of oral diseases associated with ART in PWH. We described here the processes associated with subject recruitment and retention, study visit planning, oral health assessments, bio-specimen collection and preprocessing procedures, and data management. We also highlighted the rigors and challenges associated with participant recruitment and retention.

Efficacy of switching from teriparatide to zoledronic acid or denosumab on bone mineral density and biochemical markers of bone turnover in older patients with severe osteoporosis: a real-life study

PURPOSE

Osteoporosis is characterized by loss of bone mass and susceptibility to fracture. Skeletal effects of teriparatide (TPT) are not persistent after drug withdrawal and sequential therapy with bisphosphonates or denosumab (Dmab) after TPT discontinuation represents a valid option. Here, the two sequential strategies were evaluated in severe osteoporotic patients.

METHODS

The study retrospectively enrolled 56 severe osteoporotic patients who received TPT for 24 months followed by 24 months of zoledronic acid (ZOL) (TPT + ZOL) or Dmab (TPT+Dmab). Clinical features, incident fractures, bone mineral density (BMD) measurements, and bone marker profiles were collected. One-way ANOVA analyzed the difference between mean T-scores at baseline, after 24 months of TPT, and after 2 doses of ZOL or after at least 3 doses of Dmab.

RESULTS

Twenty-three patients received TPT + ZOL (19 females, 4 males; median [IR] age, 74.3 [66.9, 78.6] years) and 33 patients received TPT+Dmab (31 females, 2 males; mean [IR] age, 66.6 ± 11.3 years). Mean lumbar and hip T-scores were increased after both TPT + ZOL and TPT+Dmab (all p < 0.05 vs baseline). The size effects induced by TPT + ZOL on the lumbar and hip BMD T-scores were similar to those observed with TPT+Dmab with mean T-scores increases of about 1 and 0.4 SD, respectively. No significant between-group differences were identified. Incident fragility fractures occurred in 3 (13%) patients treated with TPT + ZOL and in 5 (15%) patients treated with TPT+Dmab.

CONCLUSIONS

Sequential TPT + ZOL therapy is likely to increase bone mineralization at the lumbar level and to stabilize it at the femoral level, similarly to what obtained with the sequential TPT+Dmab. Both ZOL and Dmab are suggested to be effective sequential treatments after TPT.

Update of the fracture risk prediction tool FRAX: a systematic review of potential cohorts and analysis plan

We describe the collection of cohorts together with the analysis plan for an update of the fracture risk prediction tool FRAX with respect to current and novel risk factors. The resource comprises 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures.

INTRODUCTION

The availability of the fracture risk assessment tool FRAX® has substantially enhanced the targeting of treatment to those at high risk of fracture with FRAX now incorporated into more than 100 clinical osteoporosis guidelines worldwide. The aim of this study is to determine whether the current algorithms can be further optimised with respect to current and novel risk factors.

METHODS

A computerised literature search was performed in PubMed from inception until May 17, 2019, to identify eligible cohorts for updating the FRAX coefficients. Additionally, we searched the abstracts of conference proceedings of the American Society for Bone and Mineral Research, European Calcified Tissue Society and World Congress of Osteoporosis. Prospective cohort studies with data on baseline clinical risk factors and incident fractures were eligible.

RESULTS

Of the 836 records retrieved, 53 were selected for full-text assessment after screening on title and abstract. Twelve cohorts were deemed eligible and of these, 4 novel cohorts were identified. These cohorts, together with 60 previously identified cohorts, will provide the resource for constructing an updated version of FRAX comprising 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures. For each known and candidate risk factor, multivariate hazard functions for hip fracture, major osteoporotic fracture and death will be tested using extended Poisson regression. Sex- and/or ethnicity-specific differences in the weights of the risk factors will be investigated. After meta-analyses of the cohort-specific beta coefficients for each risk factor, models comprising 10-year probability of hip and major osteoporotic fracture, with or without femoral neck bone mineral density, will be computed.

CONCLUSIONS

These assembled cohorts and described models will provide the framework for an updated FRAX tool enabling enhanced assessment of fracture risk (PROSPERO (CRD42021227266)).

Sarcopenia: Body Composition and Gait Analysis

Background

Age-induced sarcopenia negatively affects walking stability and increases the risk of falls, which is the leading cause of accidental death in the elderly.

Objective

This study aimed to analyze and contrast body composition and gait characteristics in those with sarcopenia in relation to healthy controls to shed some light on the prevention of falls in elderly patients with sarcopenia.

Materials and Methods

In this study, 68 community dwellers were scanned by the Hologic QDR-4500A Dual-energy X-ray absorptiometry (DXA). The appendicular lean mass index (ALMI) results were used to distinguish the normal participants from those with sarcopenia: 24 in the sarcopenia group, and 44 into the normal group. The participants were asked to undergo gait analysis on a plantar pressure measurement system. Statistical analysis was conducted to contrast both groups' gait and butterfly parameters from their gait test, and then a gait forward dynamics method was performed to quantify the analysis for both groups.

Results

The ALMI of the female was not related to their age (r = 0.06) while that of the male was weakly related (r = 0.17). Body mass index (BMI) from both groups was normal, although with a statistically greater BMI from the normal group compared with sarcopenia (p &lt; 0.001). Greater values and significant differences were found in step length and stride length from the normal elderly group (p &lt; 0.01), and so was the length of the gait line and single support line (p &lt; 0.05). Gait forward dynamics analysis results showed no motor neural or musculoskeletal disorders in their gait performance from the sarcopenia group.

Conclusion

For the elderly, age did not largely affect the ALMI, BMI, or T-score, but BMI and ALMI were strongly correlated. In this study, significant differences were found in certain gait parameters between the elderly with sarcopenia and the normal elderly, which were related to absolute muscle strength, suggesting that sarcopenia was a disease mainly caused by decreased muscle mass. In addition, when abnormities were identified in step length, stride length, length of gait line, or length of single support line, it is proposed to take a DXA scan to confirm whether the elderly suffer from sarcopenia.

Generation of a Reference Dataset to Permit the Calculation of T-scores at the Distal Femur and Proximal Tibia in Persons with Spinal Cord Injury

Persons with traumatic spinal cord injury (SCI) have severe bone loss below the level of lesion with the distal femur (DF) and proximal tibia (PT) being the skeletal regions having the highest risk of fracture. While a reference areal bone mineral density (aBMD) database is available at the total hip (TH) using the combined National Health and Nutrition Examination Survey (NHANES) III study and General Electric (GE) combined (GE/NHANES) to calculate T-score (T-score_GE/NHANES), no such reference database exists for aBMD of the DF, and PT. The primary objectives of this study were (1) to create a reference dataset of young-healthy able-bodied (YHAB) persons to calculate T-score (T-score_YHAB) values at the DF and PT, (2) to explore the impact of time since injury (TSI) on relative bone loss in the DF and PT regions using the two computation models to determine T-score values, and (3) to determine agreement between T-score values for a cohort of persons with SCI using the (T-score_YHAB) and (T-score_GE/NHANES) reference datasets. A cross-sectional prospective data collection study. A Department of Veterans Affairs Medical Center and a Private Rehabilitation Hospital. A normative reference aBMD database at the DF and PT was collected in 32 male and 32 female Caucasian YHAB participants (n=64) and then applied to calculate T-score values at the DF and PT in 105 SCI participants from a historical cohort. The SCI participants were then grouped based on TSI epochs (E-I: TSI < 1y, E-II: TSI 1-5y, E-III: TSI 6-10y, E-IV: TSI 11-20y, E-V: TSI > 20y). N/A. The knee and hip aBMD values were obtained by dual energy X-ray absorptiometry (GE Lunar iDXA) using standard clinical software for proximal femur orthopedic knee software applications. There were no significant differences in mean aBMD values across the four YHAB age subgroups (21-25, 26-30, 31-35, and 36-40 yr of age) at the TH, DF, and PT; mean aBMD values were higher in men compared to the women at all skeletal regions of interest. Using the mean YHAB aBMD values to calculate T-score values at each TSI epoch for persons with SCI, T-score values decreased as a function of TSI, and they continued to decline for 11-20 yr. Moderate kappa agreement was noted between the YHAB and the GE/NHANES reference datasets for the T-score cutoff criteria accepted to diagnose osteoporosis (i.e., SD <-2.5). A homogeneous reference dataset of YHAB aBMD values at the DF and PT was applied to calculate T-score values in persons with chronic SCI. There was a moderate level of agreement at the TH between the YHAB and GE/NHANES reference datasets when applying the conventional T-score cutoff value for the diagnosis of osteoporosis.

Urinary free cortisol excretion is associated with lumbar bone density in patients with adrenal Cushing's syndrome

Patients with adrenal Cushing's syndrome have a poor prognosis due to the autonomous hypersecretion of endogenous cortisol from the adrenal gland. Although several clinical examinations have been developed to manifest the autonomous hypersecretion of endogenous cortisol in this syndrome, it is unknown which parameter of cortisol overproduction is best associated with the adrenal cortisol content and bone and vascular complications of this syndrome. Therefore, the present study was undertaken to evaluate the parameter(s) associated with the adrenal cortisol content in patients with adrenal Cushing's syndrome, as well as to assess the associations between these parameters and the vascular and bone complications of this syndrome. Cardiovascular factors such as blood pressure and pulse rate, glucose metabolism, lipid metabolism, renal function, and indices of arteriosclerosis, except for diastolic blood pressure, failed to show an association with the adrenal cortisol content. Twenty-four-hour urinary free cortisol excretion (ρ = 0.893, P = 0.007) and plasma cortisol levels after the 1-mg (ρ = 0.857, P = 0.014) or 8-mg (ρ = 0.900, P = 0.037) overnight dexamethasone suppression test, but not plasma cortisol levels in the morning or late at night or indices of ¹³¹I-adosterol single-photon emission computed tomography-computed tomography, were significantly and positively associated with the adrenal cortisol content. Twenty-four-hour urinary free cortisol excretion, and not plasma cortisol levels after the 1- or 8-mg overnight dexamethasone suppression test, was significantly and negatively associated with lumbar spine bone density (lumbar spine bone mineral density, ρ = -0.786, P = 0.036; lumbar spine T score, ρ = -0.883, P = 0.009; and lumbar spine Z score, ρ = -0.883, P = 0.009). These results indicate that 24-h urinary free cortisol excretion is best associated with a decrease in bone density via increased adrenal cortisol overproduction and suggest that it could be used as a marker for osteoporosis in these patients.

The Influence of DXA Hardware, Software, Reference Population and Software Analysis Settings on the Bone Mineral Density and T-Score Relationship

Different dual-energy x-ray absorptiometry (DXA) hardware can affect bone mineral density (BMD) measurements and different reference populations can affect t-scores. Long-term analyses describing differences in the relationship between BMD and t-scores are lacking. BMD-values were plotted against t-scores for 241 Lunar DXA scans on females obtained over 18 years from several centers in Sweden and Norway. The result of the plot was compared to hardware/software versions, reference populations and different software analysis settings (Basic vs Enhanced analysis for total body and Single Photon Absorptiometry (SPA) vs Lunar calibration for forearm). For the forearm compartments, we found different BMD-t-score relationships depending on the use of SPA or Lunar calibration (p<0.001). With Lunar calibration, BMD-values were 24% higher, but there was no effect on t-scores. Total body measurements with iDXA scanners and Enhanced analysis for Prodigy scanners (software version 14.10) resulted in a different BMD-t-score relationship compared to the other hardware/software versions (p<0.001), with the largest discrepancy for lower BMD-values. Switching from Basic to Enhanced analysis generally decreased BMD-values and often changed t-scores (both increased and decreased). For the femoral neck, there were two different BMD-t-score relationships caused by different reference populations (p<0.001). In contrast to total body, the difference for femoral neck was more pronounced for higher values, with little impact in the clinical decision-making area. Hardware, software, reference populations and software analysis settings can affect the BMD-t-score relationship, but do so differently for different compartments. The BMD-t-score-plot is a simple and effective tool to discover systematic differences. Longitudinal analyses of DXA scans should be performed based on raw data analyzed in "one run" with the same software version and settings, in order to avoid systematic differences.

How does proximal femur BMD of healthy Irish adults compare to NHANES III? Results of the DXA-HIP Project

This study examines the distribution of proximal femur bone mineral density in a cohort of healthy Irish adults. These values are similar to those of the NHANES III Caucasian cohorts, supporting international recommendations to use this reference group for calculating DXA T-scores and Z-scores in Irish adults.

INTRODUCTION

Bone mineral density (BMD) is widely used in the assessment and monitoring of osteoporosis. International guidelines recommend referencing proximal femur BMD measurements to NHANES III values to calculate T-scores and Z-scores, but their validity for the Irish population has not been established. In this study, we compare BMD values of healthy Irish Caucasian adults to those of Caucasian men and women in the NHANES III cohort study.

METHODS

Men and women without bone disease and/or major risk factors for fracture, and/or not taking osteoporosis medication who had a screening DXA scan (GE Lunar, Madison, USA) at one of 3 centres in the West of Ireland were selected for this study. We calculated the mean and standard deviation (SD) used by GE for calculating white female NHANES III T-scores at the femoral neck and total hip sites, and used these values to calculate white female T-scores for men and women across each decade in our study sample. We calculated mean white female T-scores for each decade for both Caucasian men and women in the NHANES III cohort using the published data. Finally, we plotted these results against those of our study population.

RESULTS

In total, 6729 (18.5%) of 36,321 adults were included in our analyses, including 5923 (88%) women. The majority of the study population were aged between 40 and 89 years. Our results show that the proximal femur BMD of healthy Irish men and women is broadly similar to that of the NHANES III reference population, especially middle-aged adults. Results differ for very young and very old adults, likely reflecting the small sample size and a referral bias. Further studies of these populations and other manufacturers could help clarify these uncertainties.

CONCLUSIONS

Our results support using the NHANES III reference population to calculate proximal femur adult T-scores and Z-scores to establish the presence or prevalence of osteoporosis in Ireland.

Automated bone mineral density prediction and fracture risk assessment using plain radiographs via deep learning

Dual-energy X-ray absorptiometry (DXA) is underutilized to measure bone mineral density (BMD) and evaluate fracture risk. We present an automated tool to identify fractures, predict BMD, and evaluate fracture risk using plain radiographs. The tool performance is evaluated on 5164 and 18175 patients with pelvis/lumbar spine radiographs and Hologic DXA. The model is well calibrated with minimal bias in the hip (slope = 0.982, calibration-in-the-large = -0.003) and the lumbar spine BMD (slope = 0.978, calibration-in-the-large = 0.003). The area under the precision-recall curve and accuracy are 0.89 and 91.7% for hip osteoporosis, 0.89 and 86.2% for spine osteoporosis, 0.83 and 95.0% for high 10-year major fracture risk, and 0.96 and 90.0% for high hip fracture risk. The tool classifies 5206 (84.8%) patients with 95% positive or negative predictive value for osteoporosis, compared to 3008 DXA conducted at the same study period. This automated tool may help identify high-risk patients for osteoporosis.

Biomechanical Computed Tomography analysis (BCT) for clinical assessment of osteoporosis

The surgeon general of the USA defines osteoporosis as "a skeletal disorder characterized by compromised bone strength, predisposing to an increased risk of fracture." Measuring bone strength, Biomechanical Computed Tomography analysis (BCT), namely, finite element analysis of a patient's clinical-resolution computed tomography (CT) scan, is now available in the USA as a Medicare screening benefit for osteoporosis diagnostic testing. Helping to address under-diagnosis of osteoporosis, BCT can be applied "opportunistically" to most existing CT scans that include the spine or hip regions and were previously obtained for an unrelated medical indication. For the BCT test, no modifications are required to standard clinical CT imaging protocols. The analysis provides measurements of bone strength as well as a dual-energy X-ray absorptiometry (DXA)-equivalent bone mineral density (BMD) T-score at the hip and a volumetric BMD of trabecular bone at the spine. Based on both the bone strength and BMD measurements, a physician can identify osteoporosis and assess fracture risk (high, increased, not increased), without needing confirmation by DXA. To help introduce BCT to clinicians and health care professionals, we describe in this review the currently available clinical implementation of the test (VirtuOst), its application for managing patients, and the underlying supporting evidence; we also discuss its main limitations and how its results can be interpreted clinically. Together, this body of evidence supports BCT as an accurate and convenient diagnostic test for osteoporosis in both sexes, particularly when used opportunistically for patients already with CT. Biomechanical Computed Tomography analysis (BCT) uses a patient's CT scan to measure both bone strength and bone mineral density at the hip or spine. Performing at least as well as DXA for both diagnosing osteoporosis and assessing fracture risk, BCT is particularly well-suited to "opportunistic" use for the patient without a recent DXA who is undergoing or has previously undergone CT testing (including hip or spine regions) for an unrelated medical condition.

A surrogate FRAX model for the Kyrgyz Republic

The hip fracture rates from Kazakhstan were used to create a surrogate FRAX® model for the Kyrgyz Republic.

INTRODUCTION

The International Society for Clinical Densitometry and International Osteoporosis Foundation recommend utilizing a surrogate FRAX model, based on the country-specific risk of death, and fracture data based on a country where fracture rates are considered to be representative of the index country.

OBJECTIVE

This paper describes a surrogate FRAX model for the Kyrgyz Republic.

METHODS

The FRAX model used the incidence of hip fracture from the neighbouring country of Kazakhstan and the death risk for the Kyrgyz Republic.

RESULTS

Compared with the model for Kazakhstan, the surrogate model gave somewhat higher 10-year fracture probabilities for men between 60 and 80 years of age and lower probabilities for men above the age of 80. For women the probabilities were similar up to the age of 75-80 years and then lower. There were very close correlations in fracture probabilities between the surrogate and authentic models (1.00) so that the use of the Kyrgyz model had little impact on the rank order of risk. It was estimated that 2752 hip fractures arose in 2015 in individuals over the age of 50 years in the Kyrgyz Republic, with a predicted increase by 207% to 8435 in 2050.

CONCLUSION

The surrogate FRAX model for the Kyrgyz Republic provides the opportunity to determine fracture probability among the Kyrgyz population and help guide decisions about treatment.

Association between Trunk Muscle Strength, Lumbar Spine Bone Mineral Density, Lumbar Scoliosis Angle, and Skeletal Muscle Volume and Locomotive Syndrome in Elderly Individuals: A Dual-Energy X-ray Absorptiometry Study

Introduction

The present study aimed to investigate the association between trunk muscle strength, lumbar spine bone mineral density (BMD), lumbar scoliosis angle (LSA), and appendicular skeletal muscle mass index (ASMI) and the severity locomotive syndrome (LS) using dual-energy X-ray absorptiometry (DXA) technology in elderly individuals.

Methods

In this cross-sectional study, we enrolled 168 individuals aged >60 years. We measured their trunk muscle strength (flexion and extension) and BMD, LSA, and ASMI using DXA. We defined degenerative lumbar scoliosis (DLS) as LSA ≥ 10° by the Cobb method using the DXA image. The locomotor function was evaluated using the timed up-and-go (TUG) test and the 25-question Geriatric Locomotive Function Scale (GLFS-25) score. Normal locomotor function, LS-1, and LS-2 were defined as a GLFS-25 score of <7, ≥7 and <16, and ≥16, respectively. We compared the three groups, analyzing the associations between all variables and the locomotor function using univariate and multivariate analyses.

Results

Although there was no significant difference in sex ratio, BMD, ASMI, and trunk-flexor strength, significant differences were observed in age (p < 0.01), the prevalence of DLS (p = 0.02), trunk-extensor strength (p < 0.01), and trunk-extensor/flexor strength ratio (p < 0.01) among the three groups. In multiple regression analyses, the significant risk factors of the TUG test were age (β = 0.26), body mass index (β = 0.36), LSA (β = 0.15), ASMI (β = -0.30), and trunk-extensor strength (β = -0.19), whereas the significant factor of the GLFS-25 score was trunk-extensor strength (β = -0.31).

Conclusions

The results indicate that it is clinically important for LS to pay careful attention not only to BMD but also to lumbar scoliosis when DXA examination of the lumbar spine is routinely conducted. Moreover, it is essential to note that trunk-extensor strength is more important than trunk-flexor strength in maintaining locomotor function in elderly individuals.

Assessing the risk of osteoporotic fractures: the Ecuadorian FRAX model

The FRAX tool incorporates data on the incidence of fractures and mortality in each country. The epidemiology of fractures changes over time, this makes it necessary to update the specific FRAX model of each population. It is shown that there are differences between old and new FRAX models in older individuals.

PURPOSE

A new FRAX® model for Ecuador was released online in April 2019. This paper describes the data used to build the revised model, its characteristics, and how intervention and assessment thresholds were constructed.

METHODS

The national rates of hip fracture incidence standardized by age and sex from the age of 40 years for 2016 were used to synthesize a FRAX model for Ecuador. For other major fractures, Ecuadorian incidence rates were calculated using ratios obtained in Malmö, Sweden, for other major osteoporotic fractures. The new FRAX model was compared with the previous model released in 2012. Assessment and intervention thresholds were based on age-specific probabilities of a major osteoporotic fracture equivalent to women with a previous fracture.

RESULTS

Fracture incidence rates increase with age. The probability of hip or major fractures at 10 years increased in patients with a clinical risk factor, lower BMI, female sex, a higher age, and a lower BMD T-score. Compared to the previous model, the new FRAX model gave similar 10-year fracture probabilities in men and women age less than70 years but substantially higher above this age. Notwithstanding, there were very close correlations in fracture probabilities between the two models (> 0.99) so that the revision had little impact on the rank order of risk.

CONCLUSIONS

The FRAX tool provides a country-specific fracture prediction model for Ecuador. This update of the model is based on the original FRAX methodology, which has been validated externally in several independent cohorts. The FRAX model is an evolving tool that is being continuously refined, as the databases of each country are updated with more epidemiological information.

Comparison of Indian Council for Medical Research and Lunar Databases for Categorization of Male Bone Mineral Density

The mainstay of diagnosis of osteoporosis is dual-energy X-ray absorptiometry (DXA) scan measuring areal bone mineral density (BMD) (g/cm²). The aim of the present study was to compare the Indian Council of Medical Research database (ICMRD) and the Lunar ethnic reference database of DXA scans in the diagnosis of osteoporosis in male patients. In this retrospective study, all male patients who underwent a DXA scan were included. The areal BMD (g/cm²) was measured at either the lumbar spine (L1-L4) or the total hip using the Lunar DXA machine (software version 8.50) manufactured by GE Medical Systems (Shanghai, China). The Indian Council of Medical Research published a reference data for BMD in the Indian population derived from the population-based study conducted in healthy Indian individuals, which was used to analyze the BMD result by Lunar DXA scan. The 2 results were compared for various values using statistical software SPSS for Windows (version 16; SPSS Inc., Chicago, IL). A total 238 male patients with a mean age of 57.2 yr (standard deviation ±15.9) were included. Overall, 26.4% (66/250) and 2.8% (7/250) of the subjects were classified in the osteoporosis group according to the Lunar database and the ICMRD, respectively. Out of the 250 sites of the DXA scan, 28.8% (19/66) and 60.0% (40/66) of the cases classified as osteoporosis by the Lunar database were reclassified as normal and osteopenia by ICMRD, respectively. In conclusion, the Indian Council of Medical Research data underestimated the degree of osteoporosis in male subjects that might result in deferring of treatment. In view of the discrepancy, the decision on the treatment of osteoporosis should be based on the multiple fracture risk factors and less reliably on the BMD T-score.

Relationship between non-alcoholic steatohepatitis, PNPLA3 I148M genotype and bone mineral density in adolescents

BACKGROUND & AIMS

It is uncertain whether non-alcoholic steatohepatitis (NASH) is a risk factor for low bone mineral density (BMD). Our aim was to investigate: (a) associations between NASH and BMD values and (b) associations between PNPLA3 I148M genotypes and BMD, in children with histologically proven non-alcoholic fatty liver disease (NAFLD).

METHODS

BMD area (g/cm² ) was measured using dual-energy X-ray absorptiometry (DEXA). NASH was diagnosed by a Steatosis, Activity and Fibrosis (SAF) score and FLIP algorithm. Genotyping for patatin-like phospholipase domain containing-3 (PNPLA3) I148M genotype (rs738409) (CC, CG and GG) was undertaken using the TaqMan SNP genotyping allelic discrimination method. Logistic regression was used to test associations [OR (95% CIs)] between low BMD, and both NASH and PNPLA3 I148M genotypes.

RESULTS

Thirty-four adolescents (mean age 13.8 ± 1.1 years) with histologically confirmed NAFLD were studied. Subjects with NASH (n = 25) had a lower BMD (means (SDs) 0.87 ± 0.06 vs 0.97 ± 0.12, P = 0.005), compared to subjects without NASH. Subjects with PNPLA3 CG+GG genotypes had a lower BMD compared with subjects with PNPLA3-CC genotype (means (SDs) 0.79 ± 0.20 vs 0.92 ± 0.10, P = 0.009). PNPLA3 CG+GG genotypes were independently associated with NASH [OR (95% CIs 1.78, 1.24, 2.99)], and low BMD was associated with both PNPLA3 CG+GG (OR 3.62 (95% CIs 1.21, 5.53), P = 0.028) and with SAF score (OR 2.76 (95% CIs 1.12, 5.41), P = 0.045).

CONCLUSIONS

Taken together the independent associations between: (a) low BMD and PNPLA3 CG+GG genotype; (b) low BMD and NASH; and (c) PNPLA3 CG+GG genotype and NASH, provide support for a causal relationship between NASH and low BMD.

The Prevalence of Osteopenia and Osteoporosis Among Malaysian Type 2 Diabetic Patients Using Quantitative Ultrasound Densitometer

Background:

Type 2 Diabetes Mellitus (T2DM) and osteoporosis are both chronic conditions and the relationship between them is complex.

Objective:

The aims of this study were to assess the prevalence of Low Bone Mineral density (LBMD, i.e., osteopenia and osteoporosis), as well as, the difference and associations between Quantitative Ultrasound Scan (QUS) parameters with socio-demographic data and clinical related data among T2DM in Penang, Malaysia.

Method:

An observational, cross-sectional study with a convenient sample of 450 T2DM patients were recruited from the outpatient diabetes clinic at Hospital Pulau Pinang (HPP) to measure Bone Mineral Density (BMD) at the heel bone using QUS. In addition, a self-reported structured questionnaire about the socio-demographic data and osteoporosis risk factors were collected. Moreover, the study included the retrospective collection of clinical data from patients’ medical records.

Results:

The mean value of T-score for normal BMD, osteopenic and osteoporotic patients’ were (-0.41±0.44), (-1.65±0.39) and (-2.76±0.27), respectively. According to QUS measurements, more than three quarters of T2DM patients (82%) were at high risk of abnormal BMD. The results showed that QUS scores were significantly associated with age, gender, menopausal duration, educational level and diabetic related data. Moreover, the QUS parameters and T-scores demonstrated significant negative correlation with age, menopausal duration, diabetic duration and glycaemic control, as well as, a positive correlation with body mass index and waist to hip ratio. The current study revealed that none of the cardiovascular disease risk factors appear to influence the prevalence of low BMD among T2DM Malaysian patients.

Conclusion:

The study findings revealed that the assessment of T2DM patients’ bone health and related factor are essential and future educational programs are crucial to improve osteoporosis management.

Measuring improvement in fracture risk prediction for a new risk factor: a simulation

Objective

Improvements in clinical risk prediction models for osteoporosis-related fracture can be evaluated using area under the receiver operating characteristic (AUROC) curve and calibration, as well as reclassification statistics such as the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) statistics. Our objective was to compare the performance of these measures for assessing improvements to an existing fracture risk prediction model. We simulated the effect of a new, randomly-generated risk factor on prediction of major osteoporotic fracture (MOF) for the internationally-validated FRAX^® model in a cohort from the Manitoba Bone Mineral Density (BMD) Registry.

Results

The study cohort was comprised of 31,999 women 50+ years of age; 9.9% sustained at least one MOF in a mean follow-up of 8.4 years. The original prediction model had good discriminative performance, with AUROC = 0.706 and calibration (ratio of observed to predicted risk) of 0.990. The addition of the simulated risk factor resulted in improvements in NRI and IDI for most investigated conditions, while AUROC decreased and changes in calibration were negative. Reclassification measures may give different information than discrimination and calibration about the performance of new clinical risk factors.

Quality in dual-energy X-ray absorptiometry scans

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated.

Significant liver fibrosis assessed using liver transient elastography is independently associated with low bone mineral density in patients with non-alcoholic fatty liver disease

Background

Metabolic bone disorders frequently occur in patients with chronic liver disease; however, the association between liver fibrosis and bone mineral density in patients with non-alcoholic fatty liver disease (NAFLD) is unclear.

Methods

This is a cross-sectional analysis of 231 asymptomatic subjects (160 women, 61.6 years old) from a university hospital setting, between February 2012 and December 2014. Bone mineral density (BMD) was measured at the lumbar spine, femur neck, and total hip using dual-energy X-ray absorptiometry (DXA). Liver fibrosis and steatosis were assessed using transient elastography.

Results

Among a total of 231 individuals, 129 subjects (55.8%) had NAFLD. BMDs at lumbar spine, femur neck, and total hip were significantly lower in patients having NAFLD with significant fibrosis, compared with patients having NAFLD without significant fibrosis (Ps<0.005). In patients with NAFLD, significant liver fibrosis revealed marked negative correlations with BMD at the lumber spine (r = –0.19, P = 0.032), femur neck (r = –0.19, P = 0.034), and total hip (r = –0.21, P = 0.016). A multivariate linear regression analysis revealed that significant liver fibrosis was independently correlated with low BMD at the femur neck (β = –0.18, P = 0.039) and total hip (β = –0.21, P = 0.005) after adjustment for age, sex, BMI, fasting plasma glucose, alanine aminotransferase, high-density lipoprotein cholesterol, and liver steatosis among patients with NAFLD. Using multivariable logistic regression, significant liver fibrosis was independently associated with overall osteopenia and osteoporosis in subjects having NAFLD (OR = 4.10, 95% CI = 1.02–16.45).

Conclusion

The presence of significant liver fibrosis assessed via TE was independently associated with low BMD in NAFLD subjects.

Epidemiology of fractures in Armenia: development of a country-specific FRAX model and comparison to its surrogate

Fracture probabilities derived from the surrogate FRAX model for Armenia were compared to those from the model based on regional estimates of the incidence of hip fracture. Disparities between the surrogate and authentic FRAX models indicate the importance of developing country-specific FRAX models. Despite large differences between models, differences in the rank order of fracture probabilities were minimal.

OBJECTIVE

Armenia has relied on a surrogate FRAX model based on the fracture epidemiology of Romania. This paper describes the epidemiology of fragility fractures in Armenia used to create an Armenia-specific FRAX model with an aim of comparing this new model with the surrogate model.

METHODS

We carried out a population-based study in two regions of Armenia (Ararat and Vayots Dzor representing approximately 11% of the country's population). We aimed to identify all low-energy fractures: retrospectively from hospital registers in 2011-2012 and prospectively in 2013 with the inclusion of primary care sources.

RESULTS

The differences in incidence between the surveys with and without data from primary care suggested that 44% of patients sustaining a hip fracture did not receive specialized medical care. A similar proportion of forearm and humeral fractures did not come to hospital attention (48 and 49%, respectively). Only 57.7% of patients sustaining a hip fracture were hospitalized. In 2013, hip fracture incidence at the age of 50 years or more was 201/100,000 for women and 136/100,000 for men, and age- and sex-specific rates were incorporated into the new "authentic" FRAX model for Armenia. Compared to the surrogate model, the authentic model gave lower 10-year fracture probabilities in men and women aged less than 70 years but substantially higher above this age. Notwithstanding, there were very close correlations in fracture probabilities between the surrogate and authentic models (> 0.99) so that the revisions had little impact on the rank order of risk.

CONCLUSION

A substantial proportion of major osteoporotic fractures in Armenia do not come to hospital attention. The disparities between surrogate and authentic FRAX models indicate the importance of developing country-specific FRAX models. Despite large differences between models, differences in the rank order of fracture probabilities were minimal.

Epidemiology of hip fracture and the development of FRAX in Ukraine

A country-specific FRAX model has been developed for the Ukraine to replace the Austrian model hitherto used. Comparison of the Austrian and Ukrainian models indicated that the former markedly overestimated fracture probability whilst correctly stratifying risk.

INTRODUCTION

FRAX has been used to estimate osteoporotic fracture risk since 2009. Rather than using a surrogate model, the Austrian version of FRAX was adopted for clinical practice. Since then, data have become available on hip fracture incidence in the Ukraine.

METHODS

The incidence of hip fracture was computed from three regional estimates and used to construct a country-specific FRAX model for the Ukraine. The model characteristics were compared with those of the Austrian FRAX model, previously used in Ukraine by using all combinations of six risk factors and eight values of BMD (total number of combinations =512).

RESULTS

The relationship between the probabilities of a major fracture derived from the two versions of FRAX indicated a close correlation between the two estimates (r > 0.95). The Ukrainian version, however, gave markedly lower probabilities than the Austrian model at all ages. For a major osteoporotic fracture, the median probability was lower by 25% at age 50 years and the difference increased with age. At the age of 60, 70 and 80 years, the median value was lower by 30, 53 and 65%, respectively. Similar findings were observed for men and for hip fracture.

CONCLUSION

The Ukrainian FRAX model should enhance accuracy of determining fracture probability among the Ukrainian population and help to guide decisions about treatment. The study also indicates that the use of surrogate FRAX models or models from other countries, whilst correctly stratifying risk, may markedly over or underestimate the absolute fracture probability.

Adjusting Hip Fracture Probability in Men and Women Using Hip Axis Length: the Manitoba Bone Density Database

Most studies report that longer hip axis length (HAL) is associated with increased hip fracture risk in women, but comparable data in men are sparse. Using a registry of all dual-energy X-ray absorptiometry (DXA) results for Manitoba, Canada, we identified 4738 men and 50,420 women aged 40 yr and older with baseline hip DXA results, HAL measurements, and Fracture Risk Assessment Tool (FRAX) hip fracture probability computed with femoral neck bone mineral density (BMD). Population-based health service records were assessed for a subsequent hospitalization with a primary diagnosis of hip fracture. During mean 6.2 yr of follow-up, 70 men and 1020 women developed incident hip fractures. Mean HAL was significantly greater in those with vs without incident hip fractures (men 123.0 ± 7.6 vs 121.3 ± 7.4 mm, p = 0.050; women 106.9 ± 6.2 vs 104.6 ± 6.2 mm, p < 0.001). When adjusted for age and femoral neck BMD, each millimeter increase in HAL increased hip fracture risk by 3.6% in men (p = 0.022) and 4.6% in women (p < 0.001); this association was unaffected by sex (p value for interaction = 0.477). When adjusted for log-transformed FRAX hip fracture probability, each millimeter increase in HAL increased hip fracture risk by 3.4% in men (p = 0.031) and 4.8% in women (p < 0.001); this association was again unaffected by sex (p interaction = 0.409). A bilinear adjustment applicable to both men and women was developed: relative increase in hip fracture probability 4.7% for every millimeter that HAL is above the sex-specific average, relative decrease in hip fracture probability 3.8% for every millimeter that HAL is below the sex-specific average. We concluded that greater DXA-derived HAL is associated with increased incident hip fracture risk in both men and women, and this risk is independent of BMD and FRAX probability.

Atividade física na vida diária e densidade mineral óssea em mulheres idosas

INTRODUÇÃO: o rápido envelhecimento da população contemporânea tem influenciado no desenvolvimento de estratégias para a prevenção da osteoporose em idosos. A atividade física diária é vista como uma possível estratégia para aumentar a massa óssea e ajudar a prevenir a perda óssea em pessoas idosas. No entanto, é essencial saber a quantidade mínima ou a intensidade adequada de atividade física que produza o aumento da massa óssea em mulheres idosas.OBJETIVO: analisar, durante uma semana, a relação entre a quantidade e a intensidade da atividade física diária com a densidade mineral óssea (DMO) da mão, por meio da quantificação de atividade física diária em idosas.MÉTODOS: a amostra do estudo foi composta por 24 mulheres (idade 66-78 anos), que realizaram atividade física, durante 7 dias, com um gravador da aceleração dos movimentos do corpo em seu pulso, para uma quantificação individual da atividade física. Para medir a densidade mineral óssea da mão direita foi utilizada a técnica de dupla absorção de raios-X (DXA).RESULTADOS: uma relação significativa entre a prática semanal e o T-score (r = 0,99) e a prática semanal horizontal e o T-score (r = 0,99) foi encontrada no osso normal e no grupo ósseo com osteoporose, respectivamente. A relação entre T-score e a quantidade de atividade física não era clara em ambos os grupos.CONCLUSÃO: na amostra analisada, foi encontrada uma associação positiva entre a maior qualidade do osso da mão e a intensidade mais elevada de atividade física. A combinação de absorciometria acelerometria e de raios-X na mão obteve resultados semelhantes ao encontrados com outros métodos menos acessíveis.

Comparison of femoral neck BMD evaluation obtained using Lunar DXA and QCT with asynchronous calibration from CT colonography

For patients undergoing screening computed tomography colonography (CTC), an opportunity exists for bone mineral density (BMD) screening without additional radiation exposure using quantitative computed tomography (QCT). This study investigated the use of dual-energy X-ray absorptiometry (DXA)-equivalent QCT Computed Tomography X-Ray Absorptiometry (CTXA) analysis at the hip obtained using CTC examinations using a retrospective asynchronous calibration of patient scans. A cohort of 33 women, age 61.3 (10.6) yr (mean [standard deviation]), had routine CTC using various GE LightSpeed CT scanner models followed after 0-9 mo by a DXA hip BMD examination using a GE Lunar Prodigy machine. Areal bone mineral density (aBMD) and T-scores of the proximal femur were measured from either prone or supine CTC examinations using Mindways QCT Pro software following standard workflow except that the CT scanners were asynchronously calibrated by phantoms scanned retrospectively of the CTC examination without the subject present. CTXA and DXA aBMD were highly correlated (R2=0.907) with a linear relationship of DXA_BMD=1.297*CTXA_BMD+0.048. The standard error of estimate (SEE) on the linear fit was 0.053 g/cm2. CTXA and DXA T-scores showed a linear relationship of DXA_T-score=1.034*CTXA_T-score+0.3 and an SEE of 0.379 T-scores. CTXA and DXA aBMD and T-score measurements showed good correlation despite asynchronous scan acquisition and retrospective QCT calibration. The SEE of 0.053 g/cm2 is on par with the literature comparing Hologic and Lunar DXA devices. The observed relationship between CTXA and Lunar DXA aBMD matches predictions from published cross-calibrations relating CTXA to DXA aBMD measurement. Thus, opportunistic use of CTXA T-scores obtained at the time of CTC could enhance osteoporosis screening.

Evaluation of the FRAX model for hip fracture predictions in the population-based Kuopio Osteoporosis Risk Factor and Prevention Study (OSTPRE)

Calibration of the Finnish FRAX model was evaluated using a locally derived population-based cohort of postmenopausal women (n = 13,917). Hip fractures were observed from national register-based data and verified from radiological records. For a subpopulation of 11,182 women, there were enough data to calculate the fracture probabilities using the Finnish FRAX tool (without bone mineral density). A 10-year period prevalence of hip fractures to this subpopulation was 0.66 %. The expected numbers of hip fractures were significantly higher than the self reported ones (O/E ratio 0.46; 95 % CI 0.33-0.63), had a tendency to be greater than the observed ones (O/E ratio 0.83; 95 % CI 0.65-1.04), and calibration in terms of goodness-of-fit of absolute probabilities was questionable (P = 0.015). Strikingly, the 10-year period prevalence of hip fractures to the whole cohort was higher (0.84 %) than for the women with FRAX measurements (0.66 %). This was mainly the result of difference between people who had and who had not responded to postal enquiries (0.71 vs. 1.77 %, P < 0.0001). Self-reports missed to capture 38 % of all hip fractures in those who responded and about 45 % of hip fractures in women who had a FRAX estimate. The Finnish FRAX tool seems to provide appropriate discrimination for hip fracture risk, but caution is required in the interpretation of absolute risk, especially if used for population that may not be representing general population per se. Our study also showed that patients with no response had significantly higher hip fracture risk and that the use of purely self-reported hip fractures in calculations results in biased incidence and period prevalence estimates. Such important biases may remain unnoticed if there are no data from other sources available.

Definition of osteoporosis by bone density criteria in men: effect of using female instead of male young reference data depends on skeletal site and densitometer manufacturer

Whether to use young male or young female reference data to calculate bone mineral density (BMD) T-scores in men remains controversial. The third National Health and Nutrition Examination and Survey (NHANES III) data show that the mean and standard deviation of femoral neck and total hip BMD is greater in young men than young women, and therefore differences in T-scores at these sites using NHANES III female vs male norms becomes less as BMD decreases. In contrast, manufacturer-specific reference databases generally assume similar standard deviations of BMD in men and women. Using NHANES III reference data for the femoral neck and total hip, respectively we found that men with T-scores of -2.5 when young male norms are used have T-scores of -2.4 and -2.3 when young female norms are used. Using manufacturer-specific reference data, we found that men with T-scores of -2.5 when young male norms are used at the femoral neck, total hip, lumbar spine, or one-third of the forearm would have T-scores ranging from -2.4 to -0.4 when young female norms are used, depending on skeletal site and densitometer manufacturer. The change of proportions of men diagnosed with osteoporosis when young female norms are used instead of young male reference data differs substantially according to skeletal site and densitometer manufacturer.

CTXA hip--an extension of classical DXA measurements using quantitative CT

Bone mineral density (BMD) estimates for the proximal femur using Dual Energy X-ray Absorptiometry (DXA) are currently considered the standard for making a diagnosis of osteoporosis in an individual patient using BMD alone. We have compared BMD results from a commercial Quantitative CT (QCT) BMD analysis system, "CTXA Hip", which provides clinical data for the proximal femur, to results from DXA. We have also used CTXA Hip to determine cortical and trabecular contributions to total BMD. Sixty-nine patients were scanned using 3D QCT and DXA. CTXA Hip BMD measurements for Total Hip and Femoral Neck were compared to DXA results. Twenty-two women were scanned at 0, 1, 2 years and CTXA Hip and DXA results analyzed for long-term reproducibility. Long-term reproducibility calculated as root-mean-square averages of SDs in vivo was 0.012 g/cm2 (CV = 1.8%) for CTXA Total Hip and 0.011 g/cm2 (CV = 2.0%) for CTXA Femoral Neck compared to 0.014 g/cm2 (CV = 2.0%) and 0.016 g/cm2 (CV = 2.7%), respectively, for DXA. The correlation of Total Hip BMD CTXA vs. DXA was R = 0.97 and for Femoral Neck was R = 0.95 (SEE 0.044 g/cm2 in both cases). Cortical bone comprised 62±5% (mean ± SD) of total hipbone mass in osteoporotic women. CTXA Hip provides substantially the same clinical information as conventional DXA and in addition provides estimates of BMD in separate cortical and trabecular bone compartments, which may be useful in evaluation of bone strength.

Country-specific young adult dual-energy X-ray absorptiometry reference data are warranted for T-score calculations in women: data from the peak-25 cohort

The aims of this study were to provide normative data for dual-energy X-ray absorptiometry (DXA) in 25-yr-old women and evaluate whether young adult Swedish women have bone mineral density (BMD) comparable with DXA manufacturer reference values and other equivalent populations. BMD at all sites was measured in the population-based Peak-25 cohort (n = 1061 women; age, 25.5 ± 0.2yr). BMD values were standardized (sBMD) and compared against the Third National Health and Nutrition Examination Survey (NHANES III) and other cohorts. Based on the DXA manufacturer-supplied reference values, Z-scores were 0.54 ± 0.98 (femoral neck [FN]), 0.47 ± 0.96 (total hip [TH]), and 0.32 ± 1.03 (lumbar spine [LS]). In comparison with other studies, sBMD was higher in the Peak-25 cohort (FN, 1.5%-8.3%; TH, 3.9%-9.2%; and LS, 2.4%-6.5%) with the exception of trochanter-sBMD which was 2.5% lower compared with NHANES III. The concordance in identifying those in the lowest or highest quartile of BMD was highest between hip measurements (low, 71%-78% and high, 70%-84%), corresponding discordance of 0%-1%. At this age, the correlation between DXA sites was strong (r = 0.62-0.94). BMD in Swedish young adult women is generally higher than has been reported in other equivalently aged European and North American cohorts and suggests that the high fracture incidence in Sweden is not explained by lower peak bone mass. The use of nonregional-specific DXA reference data could contribute to misdiagnosed osteoporosis in elderly women.

2013 International Society for Clinical Densitometry Position Development Conference: Task Force on Normative Databases

Following the standard protocol for development of Official Positions for the International Society for Clinical Densitometry, the Expert Panel heard the report and recommendations from the Task Force on Normative Databases; using the RAND methodology, agreement was reached on the following statements: 1. Manufacturers should continue to use their own databases for the lumbar spine as the reference standard for T-scores. 2. Manufacturers should continue to use National Health and Nutrition Examination Survey III data as the reference standard for femoral neck and total hip T-scores. 3. If local reference data are available, they should be used to calculate only Z-scores but not T-scores. 4. A uniform Caucasian (non-race adjusted) female reference database should be used to calculate T-scores for men of all ethnic groups.

Direct comparison of eight national FRAX® tools for fracture prediction and treatment qualification in Canadian women

SUMMARY

We compared the calibration of FRAX tools from Canada, the US (white), UK, Sweden, France, Australia, New Zealand, and China when used to assess fracture risk in 36,730 Canadian women. Our data underscores the importance of applying country-specific FRAX tools that are based upon high-quality national fracture epidemiology.

PURPOSE

A FRAX® model for Canada was constructed for prediction of hip fracture and major osteoporotic fracture (MOF) using national hip fracture and mortality data. We examined the calibration of this model in Canadian women and compared it with seven other FRAX tools.

METHODS

In women aged ≥50 years with baseline bone mineral density (BMD) measures identified from the Manitoba Bone Density Program, Canada (n = 36,730), 10-year fracture probabilities were calculated with and without BMD using selected country-specific FRAX tools. FRAX risk estimates were compared with observed fractures ≤10 years (506 hip, 2,380 MOF). Ten-year fracture risk was compared with predicted probabilities, and proportions exceeding specific treatment thresholds contrasted.

RESULTS

For hip fracture prediction, good calibration was observed for FRAX Canada and most other country-specific FRAX tools, excepting Sweden (risk overestimated) and China (risk underestimated). For MOF prediction, greater between-country differences were seen; FRAX Sweden and FRAX China showed the largest over- and underestimation in this Canadian population. Relative to treatment qualification based upon FRAX Canada, treatment of high-hip fracture probability (≥3%) was greater by FRAX Sweden (ratio 1.41 without and 1.55 with BMD), and markedly less by FRAX China (ratio 0.09 without and 0.11 with BMD). Greater between-country differences were observed for treatment of high MOF (≥20%); FRAX Sweden again greatly increased (ratio 1.76 without and 1.83 with BMD), and FRAX China severely reduced treatment qualification (ratio 0.00 without and 0.01 with BMD).

CONCLUSIONS

The use of country-specific FRAX tools, accurately calibrated to the target population, is essential. Relatively small calibration differences can have large effects on high-risk categorization and treatment qualification.

Fibroblast growth factor 23, bone mineral density, and risk of hip fracture among older adults: the cardiovascular health study

CONTEXT

Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that also inhibits calcitriol synthesis.

OBJECTIVE

Our objective was to evaluate the relationships of plasma FGF23 concentrations with bone mineral density (BMD) and hip fracture in community-dwelling older adults.

DESIGN AND SETTING

Linear regression and Cox proportional hazard models were used to examine the associations of plasma FGF23 concentrations with BMD and incident hip fracture, respectively. Analyses were also stratified by chronic kidney disease.

PARTICIPANTS

Participants included 2008 women and 1329 men ≥65 years from the 1996 to 1997 Cardiovascular Health Study visit.

MAIN OUTCOME MEASURES

Dual x-ray absorptiometry measured total hip (TH) and lumbar spine (LS) BMD in 1291 participants. Hip fracture incidence was assessed prospectively through June 30, 2008 by hospitalization records in all participants.

RESULTS

Women had higher plasma FGF23 concentrations than men (75 [56-107] vs 66 [interquartile range = 52-92] relative units/mL; P < .001). After adjustment, higher FGF23 concentrations were associated with greater total hip and lumbar spine BMD in men only (β per doubling of FGF23 = 0.02, with 95% confidence interval [CI] = 0.001-0.04 g/cm(2), and 0.03 with 95% CI = 0.01-0.06 g/cm(2)). During 9.6 ± 5.1-11.0 years of follow-up, 328 hip fractures occurred. Higher FGF23 concentrations were not associated with hip fracture risk in women or men (adjusted hazard ratio = 0.95, with 95% CI = 0.78-1.15, and 1.09 with 95% CI = 0.82-1.46 per doubling of FGF23). Results did not differ by chronic kidney disease status (P > .4 for interactions).

CONCLUSIONS

In this large prospective cohort of community-dwelling older adults, higher FGF23 concentrations were weakly associated with greater lumbar spine and total hip BMD but not with hip fracture risk.

Bone loss in chronic hemiplegia: a longitudinal cohort study

The purpose of this study was to evaluate hemiplegic stroke patients in terms of long-term changes in bone mineral density and related factors. We conducted a longitudinal cohort study, involving 57 first-stroke patients (40 males) with chronic hemiplegia (for more than 12mo), at a university rehabilitation center in the city of São Paulo, Brazil. Bone loss, body composition, lean mass, and fat mass were evaluated at 2 time points (mean interval, 16mo). Bone loss was significantly greater in paretic forearms than in nonparetic forearms (p=0.001) and in patients having suffered strokes more recently (p=0.015). We found no difference between paretic and nonparetic femurs. Femoral bone loss was significantly greater in patients using anticoagulants or anticonvulsants (p=0.025) and in those with greater spasticity (p=0.040), regardless of the time since stroke. Our results provide additional evidence that hemiplegic stroke patients have progressive bone loss and that such bone loss is more common in the arms than in the legs. Patients with poststroke hemiplegia should be densitometric monitored mainly in paretic arm and treated for bone loss, with attention to the determinants identified in this study.

Effects of anti-resorptive agents on trabecular bone score (TBS) in older women

We evaluated the longitudinal effects of anti-resorptive agents (534 treated women vs. 1,150 untreated) on lumbar spine bone mineral density (BMD) and trabecular bone score (TBS). TBS was responsive to treatment in women over age 50. The treatment-related increase in TBS was less than the increase in BMD, which is consistent with bone texture preservation.

INTRODUCTION

In addition to inducing an increase in BMD, anti-resorptive agents also help to preserve bone architecture. TBS, a new gray-level texture measurement, correlates with 3D parameters of bone micro-architecture independent of BMD. Our objective was to evaluate the longitudinal effects of anti-resorptive agents on lumbar spine BMD and TBS.

METHODS

Women (≥ 50 years), from the BMD program database for the province of Manitoba, Canada, who had not received any anti-resorptive drug prior to their initial dual X-ray absorptiometry (DXA) exam were divided into two groups: untreated, those without any anti-resorptive drug over the course of follow-up, and treated, those with a non-estrogen anti-resorptive drug (86 % bisphosphonates, 10 % raloxifene, and 4 % calcitonin). Lumbar spine TBS was calculated for each lumbar spine DXA examination. Changes in TBS and BMD between baseline and follow-up (mean follow-up 3.7 years), expressed in percentage per year, were compared between the two groups.

RESULTS

A total of 1,150 untreated women and 534 treated women met the inclusion criteria. Only a weak correlation was seen between BMD and TBS in either group. Significant intergroup differences in BMD change and TBS change were observed over the course of follow-up (p < 0.001). Similar mean decreases in BMD and TBS (-0.36 %/year and -0.31 %/year, respectively) were seen for untreated subjects (both p < 0.001). Conversely, treated subjects exhibited a significant mean increase in BMD (+1.86 %/year, p < 0.002) and TBS (+0.20 %/year, p < 0.001).

CONCLUSION

TBS is responsive to treatment with non-estrogen anti-resorptive drug therapy in women over age 50. The treatment-related increase in TBS is less than the increase in BMD, which is consistent with bone texture preservation.

The osseointegration behavior of titanium-zirconium implants in ovariectomized rabbits

OBJECTIVE

The aim of this study is to compare the osseointegration behavior of titanium (Ti) and titanium-zirconium (TiZr) implants in ovariectomized (OVX) rabbits.

MATERIALS AND METHODS

Twelve ovariectomized New Zealand rabbits submitted to a hypocalcic diet and 12 sham-aged rabbits were used. After the bone mass loss induction period, TiZr or Ti implants both benefiting from a SLActive surface treatment were randomly inserted in the tibia and femur of each animal. The total of 24 rabbits were divided in four groups (n = 6): SHAM + Ti, OVX + Ti, SHAM + TiZr,OVX + TiZr. The animals were respectively sacrificed 3 and 6 weeks after dental implant placement. Six implants in each group at each time point were subjected to removal torque testing, and the remaining implants were prepared for histomorphometric analysis.

RESULTS

At the end of the healing period, all implants were osseointegrated. The removal torque value of the SHAM-TiZr group was significantly higher than those of the SHAM-Ti group (P < 0.001). The removal torque of the OVX-Ti group was significantly lower than those of the OVX-TiZr group. All groups demonstrated an increase in the peak torque value after 6 weeks: 46.0 and 50.8 Ncm for the OVX and the SHAM animals, respectively, in the case where Ti implants were used. When TiZr implants were inserted, the values reached 60.7 and 76.2 Ncm with a similar group configuration. The BIC and the BA/TA analysis showed an increase between week 3 and 6 in the case of nonovariectomized animals. From week 3 to 6, the BIC went from 37.1 ± 14.3 to 47.7 ± 8.7 for the SHAM + Ti group and from 37.6 ± 10.9 to 50.4 ± 11 for the SHAM + TiZr group. The BIC values were not significantly different between groups.

CONCLUSION

The parameters intended to be representative of the bone morphology (BIC & BATA) did not help to discriminate between Ti and TiZr which appeared to behave similarly in this experimental model. However, the removal torque values for the TiZr group were statistically higher than those of the Ti group in both the SHAM and the ovariectomized animals. That likely reflected an increased quality of bone around the TiZr implants.

Competing mortality and fracture risk assessment

SUMMARY

Failure to account for competing mortality gave higher estimates of 10-year fracture probability than if appropriate adjustment is made for competing mortality, particularly among subgroups with higher mortality. A modified Kaplan-Meier method is easy to implement and provides an alternative approach to existing methods for competing mortality risk adjustment.

INTRODUCTION

A unique feature of FRAX(®) is that 10-year fracture probability accounts for mortality as a competing risk. We compared the effect of competing mortality adjustment on nonparametric and parametric methods of fracture probability estimation.

METHODS

The Manitoba Bone Mineral Density (BMD) database was used to identify men and women age ≥50 years with FRAX probabilities calculated using femoral neck BMD (N = 39,063). Fractures were assessed from administrative data (N = 2,543 with a major osteoporotic fracture, N = 549 with a hip fracture during mean 5.3 years follow-up).

RESULTS

The following subgroups with higher mortality were identified: men, age >80 years, high fracture probability, and presence of diabetes. Failure to account for competing mortality in these subgroups overestimated fracture probability by 16-56 % with the standard nonparametric (Kaplan-Meier) method and 15-29 % with the standard parametric (Cox) model. When the outcome was hip fractures, failure to account for competing mortality overestimated hip fracture probability by 18-36 % and 17-35 %, respectively. A simple modified Kaplan-Meier method showed very close agreement with methods that adjusted for competing mortality (within 2 %).

CONCLUSIONS

Failure to account for competing mortality risk gives considerably higher estimates of 10-year fracture probability than if adjustment is made for this competing risk.

Does osteoporosis therapy invalidate FRAX for fracture prediction?

Ten-year fracture risk assessment with the fracture risk assessment system (FRAX) is increasingly used to guide treatment decisions. Osteoporosis pharmacotherapy reduces fracture risk, but the effect is greater than can be explained from the increase in bone mineral density (BMD). Whether this invalidates fracture predictions with FRAX is uncertain. A total of 35,764 women (age ≥50 years) and baseline BMD testing (1996–2007) had FRAX probabilities retroactively calculated. A provincial pharmacy database was used to identify osteoporosis medication use. Women were categorized as untreated, current high adherence users [medication possession ratio (MPR) ≥0.80 in the year after BMD testing], current low adherence users (MPR <0.80), and past users. Fractures outcomes to 10 years were established form a population-based health data repository. FRAX and femoral neck BMD alone stratified major osteoporotic and hip fracture risk within untreated and each treated subgroup (all p-values <0.001) with similar area under the receiver operating characteristic curve. In untreated and each treated subgroup, a stepwise gradient in observed 10-year major osteoporotic and hip fracture incidence was found as a function of the predicted probability tertile (all p-values <0.001 for linear trend). Concordance (calibration) plots for major osteoporotic fractures and hip fractures showed good agreement between the predicted and observed 10-year fracture incidence in untreated women and each treated subgroup. Only in the highest risk tertile of women highly adherent to at least 5 years of bisphosphonate use was observed hip fracture risk significantly less than predicted, though major osteoporotic fracture risk was similar to predicted. In summary, this work suggests that the FRAX tool can be used to predict fracture probability in women currently or previously treated for osteoporosis. Although FRAX should not be used to assess the reduction in fracture risk in individuals on treatment, it may still have value for guiding the need for continued treatment or treatment withdrawal

A comparative study of using non-hip bone density inputs with FRAX®

Use of lumbar spine T-score or minimum T-score as a bone mineral density (BMD) input to the FRAX® algorithm led to miscalibration compared with the recommended femoral neck input. Use of a weighted mean between the lumbar spine and femoral neck T-scores was found to provide an arithmetically equivalent result to a previously described offset adjustment.

INTRODUCTION

FRAX assumes that the BMD input, when used in the calculation, is from the femoral neck. Use of other BMD inputs is not recommended, but there are no studies describing how this affects the performance of FRAX.

METHODS

Ten-year probabilities of a major osteoporotic fracture were calculated with different BMD inputs for 20,477 women and men aged 50 years and older from Manitoba, Canada. FRAX probability calculated with femoral neck BMD was designated the reference method. We also derived FRAX probabilities where the BMD input was based upon the lumbar spine T-score, minimum T-score (lumbar spine or femoral neck), weighted mean T-score (lumbar spine or femoral neck), or used an adjustment for the spine-hip T-score difference (offset). Fracture outcomes were assessed using a population-based administrative data repository.

RESULTS

All FRAX models showed good risk stratification with minimal differences. There was no consistent improvement in FRAX performance when lumbar spine or minimum T-score were used as inputs, but calibration was adversely affected due to higher mean fracture probabilities compared with the femoral neck. The weighted mean T-score was found to be equivalent to the spine-hip T-score offset adjustment, and both slightly improved risk classification without a change in calibration.

CONCLUSIONS

The choice of BMD input to the FRAX model has a large effect on performance. The lumbar spine T-score or minimum T-score should not be used as inputs to the FRAX algorithm. Use of a weighted mean between the lumbar spine and femoral neck T-scores slightly improves risk classification.

High fracture probability with FRAX usually indicates densitometric osteoporosis: implications for clinical practice

Most patients designated as high risk of fracture using fracture risk assessment tool (FRAX) with femoral neck bone mineral density (BMD) (i.e., 10-year major osteoporotic fracture probability exceeding 20% or hip fracture exceeding 3%) have one or more T-scores in the osteoporotic range; conversely, almost no high risk patients have normal T-scores at all bone mineral density measurement sites.

INTRODUCTION

We determined the agreement between a FRAX designation of high risk of fracture [defined as 10-year major osteoporotic fracture probability (≥ 20%) or hip fracture probability (≥ 3%)] and the WHO categorizations of bone mineral density according to T-score.

METHODS

Ten-year FRAX probabilities calculated with femoral neck BMD were derived using both Canadian and US white tools for a large clinical cohort of 36,730 women and 2,873 men age 50 years and older from Manitoba, Canada. Individuals were classified according to FRAX fracture probability and BMD T-scores alone.

RESULTS

Most individuals designated by FRAX as high risk of major osteoporotic fracture had a T-score in the osteoporotic range at one or more BMD measurement sites (85% with Canadian tool and 83% with US white tool). The majority of individuals deemed at high risk of hip fracture had one or more T-scores in the osteoporotic range (66% with Canadian tool and 64% with US white tool). Conversely, there were extremely few individuals (<1%) who were at high risk of major osteoporotic or hip fracture with normal T-scores at all BMD measurement sites.

CONCLUSIONS

A FRAX designation of high risk of fracture is usually associated with a densitometric diagnosis of osteoporosis.

Bone microarchitecture assessed by TBS predicts osteoporotic fractures independent of bone density: the Manitoba study

The measurement of BMD by dual-energy X-ray absorptiometry (DXA) is the "gold standard" for diagnosing osteoporosis but does not directly reflect deterioration in bone microarchitecture. The trabecular bone score (TBS), a novel gray-level texture measurement that can be extracted from DXA images, correlates with 3D parameters of bone microarchitecture. Our aim was to evaluate the ability of lumbar spine TBS to predict future clinical osteoporotic fractures. A total of 29,407 women 50 years of age or older at the time of baseline hip and spine DXA were identified from a database containing all clinical results for the Province of Manitoba, Canada. Health service records were assessed for the incidence of nontraumatic osteoporotic fracture codes subsequent to BMD testing (mean follow-up 4.7 years). Lumbar spine TBS was derived for each spine DXA examination blinded to clinical parameters and outcomes. Osteoporotic fractures were identified in 1668 (5.7%) women, including 439 (1.5%) spine and 293 (1.0%) hip fractures. Significantly lower spine TBS and BMD were identified in women with major osteoporotic, spine, and hip fractures (all p < 0.0001). Spine TBS and BMD predicted fractures equally well, and the combination was superior to either measurement alone (p < 0.001). Spine TBS predicts osteoporotic fractures and provides information that is independent of spine and hip BMD. Combining the TBS trabecular texture index with BMD incrementally improves fracture prediction in postmenopausal women.

Longitudinal evaluation of bone mineral density and body composition in patients with positive celiac serology

Untreated celiac disease is associated with lower bone mineral density (BMD), body weight and fat mass compared with controls. There are few longitudinal studies examining changes in body composition after celiac disease diagnosis. The aim of this study was to compare changes in BMD and body composition in celiac seropositive cases who had undergone baseline and follow-up dual energy x-ray absorptiometry (DXA) with seronegative controls. Celiac serologic and BMD databases for the Province of Manitoba, Canada, were linked. Endomysial antibody (EMA) seropositive cases and EMA seronegative controls over age 40 who had serologic testing within 6 months of DXA testing and a follow-up DXA were extracted from the databases. Changes in BMD, BMI and body composition were compared in the 2 groups. The 43 EMA seropositive cases had lower baseline spine and hip BMD, BMI and fat measurements compared with 233 EMA seronegative controls. For seropositive versus seronegative individuals there were greater increases in mean spine BMD (4.6%/year vs 0.7% spine, p < 0.0001), hip BMD (3.0 %/year vs 0.2%/year hip, p < 0.0001), and body weight (2.8%/year vs 0.3%/year, p < 0.0001). Increases in mean abdominal fat (2.4%/year vs 0.4%/year, p < 0.0001) were also greater in seropositive versus seronegative individuals, while increases in hip fat were less marked (0.9%/year vs 0.3%/year, p = 0.0071). This longitudinal database study documents significant improvements in BMD in seropositive cases. BMI and fat measures also increased, with the abdominal fat compartment demonstrating the greatest increase. Further studies are needed to determine the clinical significance of this regional increase in abdominal fat.

Characterization of osteopenia/osteoporosis in adult scoliosis: does bone density affect surgical outcome?

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study is to validate the prevalence of low bone mineral density (BMD) in woman patients with adult scoliosis and to relate that to surgical treatment outcome. Despite reports of the high prevalence of low BMD among female with adolescent idiopathic, these findings have not been substantiated in any comprehensive review of adult scoliosis patients undergoing surgical treatment.

SUMMARY OF BACKGROUND DATA

It has been suggested that scoliosis may predispose to osteoporosis and that degenerative scoliosis could falsely elevate spinal BMD measurements with dual energy radiograph absorptiometry (DXA). The discordance between hip and spine BMD measurement using DXA has also been shown in previous cross-sectional study for adult population.

METHODS

A retrospective review of 176 women treated surgically for scoliosis. BMD of the lumbar spine and femoral neck were determined by DXA. Patients were categorized as follows: concordance (osteoporosis, osteopenia, or normal BMD on both sites), minor discordance (osteoporosis in one site and osteopenia in the other site), and major discordance (osteoporosis in one site and normal the other site). Body mass index (BMI), preoperative Cobb angle, fusion ratio, and complication were recorded. Statistical analysis included the Student t test, χ(2) test, regression coefficient test, and simple linear regression. P value was set at P < 0.05.

RESULTS

The mean age was 51 ± 12 years (26-82 years). The mean T score of the hip was -1.23 ± 0.89 and of the spine was -0.52 ± 1.57. Major discordance in BMD 7 (4%) points, minor discordance 68 (39%) points, and concordance was 101 (57%) points. There was moderate correlation between T score of hip and spine (R = 0.55P < 0.01). T score of the hip and of the spine showed 10.8% and 10.2% of the patients were osteoporotic. The mean Z score of the hip and of the spine showed comparable age and sex matched values. No correlation was observed between BMD and Cobb angle (R = 0.05, P = 0.464). The fusion rate was 93% and surgical complication rate was 14.9%. No significant correlation was observed between BMD and fusion (P = 0.80) complication (P = 0.13).

CONCLUSION

Comparable bone density exists among adult scoliosis patients with no correlation between BMD and curve magnitude, fusion and complication rates. The difference in BMD of the hip and of spine cannot be fully explained in the review. These results will guide in surgical planning, patient selection on the treatment options.

Evaluation of FRAX to characterise fracture risk in Poland

The UK FRAX model was evaluated retrospectively in Polish women assessed 11 years previously for fracture risk. Results were compared with fracture risk observed during follow-up. The UK model can be used to stratify risk, but caution is required in interpretation of absolute fracture risk.

INTRODUCTION

In the absence of a FRAX® model for Poland, the UK FRAX tool has been widely used. The aim of this study was to evaluate the validity of the surrogate model in a Polish setting.

METHODS

We studied a convenience sample of 501 women who had been referred for the assessment of bone mineral density and clinical risk factors 9-12 years previously. Incident fractures in the intervening period were self-reported by telephone interview. Fracture probabilities, calculated using the UK FRAX tool, were compared to the incidence of new fractures during follow-up.

RESULTS

Incident fractures were reported in 106 women. Incident fractures of the major osteoporotic fractures were reported in 89 women. The observed incidence of fractures rose progressively in women according to percentile of fracture probability. Between the 10th and 90th percentiles, hip fracture probability computed with bone mineral density (BMD) differed 49-fold. The range was fivefold in the case of a major osteoporotic fracture. The observed/expected ratio for fracture was significantly greater than unity when the expected number was calculated without BMD (1.79; 95% confidence interval = 1.44-2.21) and when BMD was included in the FRAX calculation (1.94; 95% confidence interval = 1.45-2.54).

CONCLUSION

The UK FRAX tool categorised fracture risk well in this Polish cohort but significantly overestimated fracture risk. The UK model can be used to stratify risk in the population, but caution is required in interpretation of absolute risk.

Epidemiology of osteoporosis in an isolated Sardinian population by using quantitative ultrasound

This study aimed at estimating the prevalence of osteoporosis and osteopenia in a Sardinian isolated population using hand quantitative ultrasound and at investigating the associated factors. The authors utilized a subset of data from a large population-based epidemiologic survey carried out in the Ogliastra region of Sardinia between 2003 and 2008. The sample consists of 6,326 men and women aged ≥30 years, who underwent quantitative ultrasound at the phalanges, bioelectrical impedance, anthropometric measurements, blood tests, and a standardized epidemiologic questionnaire collecting sociodemographic, lifestyle, medical, physiologic, and pharmacologic data. The T-score thresholds for amplitude-dependent speed of sound of -3.2 standard deviations and between -3.2 and -1 standard deviations were used to diagnose osteoporosis and osteopenia, respectively. Prevalence of osteoporosis was 17.0% in women and 5.2% in men. Logistic regression analysis revealed that factors associated with osteoporosis were age, anthropometric and bioimpedance measures, alkaline phosphatase levels, and menopause in women. High education, exercise, and beer consumption seem to be protective factors, whereas a family history of osteoporosis is a risk factor. Results show that osteoporosis in this population is comparable with that found in different countries, suggesting that quantitative ultrasound could be used more widely to detect high-risk individuals for preventing osteoporotic fractures.

Effects of FRAX(®) model calibration on intervention rates: a simulation study

The WHO fracture risk assessment tool (FRAX(®)) estimates an individual's 10-yr major osteoporotic and hip fracture probabilities using a tool customized to the fracture epidemiology of a specific population. Incorrect model calibration could therefore affect performance of the model in clinical practice. The current analysis was undertaken to explore how simulated miscalibration in the FRAX(®) tool would affect the numbers of individuals meeting specific intervention criteria (10-yr major osteoporotic fracture probability ≥20%, 10-yr hip fracture probability ≥3%). The study cohort included 36,730 women and 2873 men aged 50yr and older with FRAX(®) probability estimates using femoral neck bone mineral density. We simulated relative miscalibration error in 10% increments from -50% to +50% relative to a correctly calibrated FRAX(®) model. We found that small changes in model calibration (even on the order of 10%) had large effects on the number of individuals qualifying for treatment. There was a steep gradient in the relationship between relative change in calibration and relative change in intervention rates: for every 1% change in calibration, there was a 2.5% change in intervention rates for women and 4.1% for men. For hip fracture probability, the gradient of the relationship was closer to unity. These results highlight the importance of FRAX(®) model calibration, and speak to the importance of using high-quality fracture epidemiology in constructing FRAX(®) tools.

Absolute fracture risk assessment using lumbar spine and femoral neck bone density measurements: derivation and validation of a hybrid system

The World Health Organization (WHO) Fracture Risk Assessment Tool (FRAX) computes 10-year probability of major osteoporotic fracture from multiple risk factors, including femoral neck (FN) T-scores. Lumbar spine (LS) measurements are not currently part of the FRAX formulation but are used widely in clinical practice, and this creates confusion when there is spine-hip discordance. Our objective was to develop a hybrid 10-year absolute fracture risk assessment system in which nonvertebral (NV) fracture risk was assessed from the FN and clinical vertebral (V) fracture risk was assessed from the LS. We identified 37,032 women age 45 years and older undergoing baseline FN and LS dual-energy X-ray absorptiometry (DXA; 1990-2005) from a population database that contains all clinical DXA results for the Province of Manitoba, Canada. Results were linked to longitudinal health service records for physician billings and hospitalizations to identify nontrauma vertebral and nonvertebral fracture codes after bone mineral density (BMD) testing. The population was randomly divided into equal-sized derivation and validation cohorts. Using the derivation cohort, three fracture risk prediction systems were created from Cox proportional hazards models (adjusted for age and multiple FRAX risk factors): FN to predict combined all fractures, FN to predict nonvertebral fractures, and LS to predict vertebral (without nonvertebral) fractures. The hybrid system was the sum of nonvertebral risk from the FN model and vertebral risk from the LS model. The FN and hybrid systems were both strongly predictive of overall fracture risk (p < .001). In the validation cohort, ROC analysis showed marginally better performance of the hybrid system versus the FN system for overall fracture prediction (p = .24) and significantly better performance for vertebral fracture prediction (p < .001). In a discordance subgroup with FN and LS T-score differences greater than 1 SD, there was a significant improvement in overall fracture prediction with the hybrid method (p = .025). Risk reclassification under the hybrid system showed better alignment with observed fracture risk, with 6.4% of the women reclassified to a different risk category. In conclusion, a hybrid 10-year absolute fracture risk assessment system based on combining FN and LS information is feasible. The improvement in fracture risk prediction is small but supports clinical interest in a system that integrates LS in fracture risk assessment.

Spine-hip discordance and fracture risk assessment: a physician-friendly FRAX enhancement

The FRAX® tool estimates a 10-year probability of fracture based upon multiple clinical risk factors and an optional bone mineral density (BMD) measurement obtained from the femoral neck. We describe a simple procedure for using lumbar spine BMD to enhance fracture risk assessment under the FRAX system.

INTRODUCTION

Discordance between lumbar spine (LS) and femoral neck (FN) T-scores is common and a source of clinical confusion since the LS measurement is not an input variable for the FRAX algorithm. The purpose of this study is to develop a procedure for adjusting FRAX probability based upon the T-score difference between the LS and FN (termed offset).

METHODS

The Manitoba BMD database was used to identify baseline LS and FN dual-energy X-ray absorptiometry examinations (33,850 women and 2,518 men age 50 and older) with FRAX estimates for a major osteoporotic fracture categorized as low (<10%), moderate (10-20%), and high (>20%). Fracture outcomes were assessed from population-based administrative data. An approach was developed and internally validated using a split-cohort design.

RESULTS

The offset was found to significantly affect fracture risk [HR, 1.12 (95% CI, 1.06-1.18) per SD LS below FN] independent of the FRAX probability. The following rule was formulated: "Increase/decrease FRAX estimate for a major fracture by one tenth for each rounded T-score difference between LS and FN." In the validation subgroup, there was a significant improvement in the fracture prediction using FRAX with the proposed offset adjustment for major osteoporotic (P = 0.007) and vertebral fracture prediction (P < 0.001). For those at moderate risk under FRAX, 12.6% showed reclassification using the offset to a risk level that more accurately reflected their observed risk (25.2% reclassification for moderate risk discordant cases).

CONCLUSION

A simple procedure that incorporates the offset between the LS and FN T-scores can enhance fracture risk prediction under the FRAX system.