Spine Dual X-ray Absorptiometry Research Articles

Development of an opportunistic diagnostic prediction algorithm for osteoporosis and fragility fracture risk estimates from forearm radiographs (The OFFER1 Study).

Osteoporosis and associated fractures are an increasingly prevalent concern with an ageing population. This study reports testing of IBEX Bone Health (IBEX BH) software, applied following acquisition of forearm radiographs. IBEX Bone Health analyses the radiograph to measure areal bone mineral density (aBMD) at the examination site. A non-randomized cross-sectional study design was performed involving 261 (254 after exclusions) participants (112/142m/f; mean age 70.8years (SD+/-9.0); 53 with osteoporosis). They underwent posterior-anterior distal forearm radiographs; dual X-ray absorptiometry (DXA) of the wrists, hips, and lumbar spine; and questionnaires exploring clinical risk factors. IBEX Bone Health automatically identifies regions of interest (ROI) at the ultra-distal (UD) and distal third (TD) regions of the radius. Analysis investigated area under the receiver operating characteristics curve performance of IBEX BH for prediction of (i) osteoporosis (based on clinical reporting of the hip and spine DXA) and (ii) treatment recommendations by Fracture Risk Assessment Tool (FRAX) inclusive of neck of femur (NoF) areal bone mineral density (aBMD) results following National Osteoporosis Guideline Group (NOGG) guidelines. Area under the receiver operating characteristics curve for osteoporosis prediction at the UD and TD ROIs were 0.86 (99% confidence interval (CI) [0.80, 0.91]) and 0.81 (99% CI [0.75, 0.88]), respectively. Area under the receiver operating characteristics curve for treatment recommendation using FRAX inclusive of NoF aBMD at the UD and TD ROIs were 0.95 (99% CI [0.91, 1.00]) and 0.97 (99% CI [0.93,1.00]), respectively. With a matched sensitivity to FRAX (without NoF aBMD) 0.93 (99% CI [0.78, 0.99]), IBEX BH predicted at the UD and TD ROIs recommended treatment outcomes by NOGG guidelines using FRAX (with NoF aBMD) with specificity 0.89 (99% CI 0.83, 0.94]) and 0.93 (99% CI [0.87, 0.97]), respectively. This is compared with 0.60 (99% CI [0.51, 0.69]) for FRAX (without NoF aBMD). Results demonstrate the potential clinical utility of IBEX BH as an opportunistic screening tool.

A243 BONE MINERAL DENSITY AND DIETARY BONE NUTRIENTS DIFFER IN PATIENTS WITH CROHN'S DISEASE STRICTURES

Abstract Background Crohn’s disease (CD) phenotypes include inflammatory (non-stricture) and stricture behaviours. Strictures are bowel narrowing’s that may lead to obstructions and subsequent dietary restrictions to prevent blockages. Bone mineral density (BMD) in CD is affected by many factors including corticosteroid use, CD itself, but also dietary changes. Clinical gold standard for measuring BMD is by dual x-ray absorptiometry (DXA) scans. High-resolution peripheral quantitative computed tomography (HR-pQCT), a more precise imaging modality assesses volumetric BMD, bone geometry and bone microarchitecture. We aim to compare dietary intake, and bone quality in both stricture and non-stricture CD. Aims To identify nutritional patterns, bone quality differences and deficiencies between two subtypes of CD; including energy intake, dietary components and/or micronutrients Methods Individuals (≥55 years old) with ileal CD strictures (fixed, angulated bowel or thickened bowel with pre-stenotic dilation on diagnostic imaging), or inflammatory CD were prospectively recruited. Patients with short gut, celiac disease, dysphagia history were excluded. All patients completed DXA hip and spine scans and HR-pQCT radius and tibia scans. Dietary assessment questionnaires (Automated Self-Administered 24-hour Dietary Assessment Tool (ASA24), and Diet History Questionnaire III for food frequency over the past year were completed. Results 56 (27 inflammatory (48% female, mean age 64.2, BMI 28.7, 16 years CD duration) and 29 strictures (45% female, mean age 65.9, BMI 27.3, 25 years CD duration, 15 (51.7%) prior bowel resection) were included. 31/56 (55.4%) patients were on biologics and 11 (19.5%) had past corticosteroid exposure. DXA-based BMD for stricture versus non-stricture CD patients was not significantly different at the hip or spine. However, HR-pQCT-based radial total BMD (p=0.03), cortical thickness (p=0.01) and cortical area (p=0.04) were lower in stricture than non-stricture patients.11 (7 stricture, 4 inflammatory) patients with past steroids consumed more dairy (p=0.01), vitamin D (p = 0.04), and calcium (p=0.03) than other CD patients. Stricture patients had significantly less consumption of vitamin K (p=0.001), vegetables (p=0.02), calcium (p=0.03), and dairy (p=0.03). Conclusions Patients with CD strictures have lower BMD and cortical bone quality at the radius than those without strictures. Patients with CD strictures also consume significantly less vitamin K, calcium, and dairy, all vital dietary components to prevent OP, compared to non-stricture patients. Overall, the skeletal fracture risk is likely much greater in CD patients with strictures than without, due to greater inherent bone fragility, and less consumption of key nutrition building blocks of bones. Funding Agencies Koopmans Memorial Research Fund

A225 QUANTIFICATION OF BONE DENSITY AND DIETARY RISK FACTORS FOR BONE FRAGILITY IN INFLAMMATORY BOWEL DISEASE

Abstract Background Nutrition and bone fracture risk are intimately related in inflammatory bowel disease (IBD). Crohn’s disease (CD) patients are at increased risk of low bone mineral density (BMD) and fractures. This may be due to chronic inflammation, corticosteroid exposure, inadequate consumption of nutrients and minerals such as calcium (ie. lactose intolerance), food aversion, bowel symptoms, and/or possible altered absorption. Fibrostenotic CD is characterized by debilitating strictures where patients are known to alter food intake to avoid obstructive symptoms. However, relationships between food intake patterns and BMD have not been well delineated according to CD phenotypes. Purpose Our study evaluated 1) BMD as measured by dual X-ray absorptiometry (DXA), and 2) energy intake, dietary components and/or micronutrients in CD patients with strictures versus inflammatory (non-stricture) behaviour. Method In this prospective pilot study, patients > 55 years old with ileal CD strictures or inflammatory behavior were recruited from the University of Calgary IBD clinic. All patients completed hip and spine DXA scans and two dietary assessment questionnaires: 1) The Automated Self-Administered 24-hour Dietary Assessment Tool (ASA24) and 2) the Diet History Questionnaire III (DHQ III). Additional data collected included past fracture history, medication (glucocorticoid exposure), smoking, and surgical history. Standard of care laboratory investigations obtained included C-reactive protein, parathyroid hormone, calcium, albumin, and 25-hydroxyvitamin D. Patients with celiac disease, cirrhosis, heart failure, kidney disease, short gut, estrogen use, and dysphagia were excluded. Independent samples t-test and multi-variable regression analyses was conducted. Result(s) Seventeen patients had stricturing and twelve had non-stricturing CD (demographics Table 1). The mean BMD for non-stricturing CD patients was not significantly different from those with a stricturing CD phenotype (p =0.140). Non-stricture patients consumed significantly more dairy, calcium, and phosphate. For all CD patients, there was a positive correlation with BMD and intake of fat (p=0.03), carbohydrates (p=0.01), fiber (p=0.01), and alcohol (p=0.01). There was no statistically significant difference in corticosteroid exposure or smoking status. 74.7% (11/17) patients with stricturing CD had past bowel resection compared to only one patient with non-stricturing CD. Image Conclusion(s) In this pilot study, there was no difference in BMD between CD patients with and without small bowel strictures despite inflammatory behaviour patients having less surgical resections and consuming more calcium rich foods known to improve BMD. Further studies may delineate the dietary differences among CD phenotypes and provide information for interventions for nutrient supplementation, and a greater understanding of their relationships with BMD. Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; Koopmans Memorial Research Fund Disclosure of Interest None Declared

Bone Marrow Adipose Tissue Is Increased in Postmenopausal Women With Postsurgical Hypoparathyroidism.

Suppression of bone turnover, greater trabecular volume, and normal-high normal all-site bone mineral density (BMD) are hallmarks of postsurgical hypoparathyroidism (HypoPT). Impairment in the trabecular microarchitecture with possible higher risk of vertebral fractures (VF) in women with postmenopausal HypoPT has also been described. Currently, no data on bone marrow adipose tissue (BMAT) are available in HypoPT. To assess BMAT by magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) in postmenopausal women with chronic postsurgical HypoPT. This cross-sectional pilot study, conducted at an ambulatory referral center, included 29 postmenopausal women (mean age 66 ± 8.4 years) with postsurgical HypoPT and 31 healthy postmenopausal women (mean age 63 ± 8.5). Lumbar spine MRI was performed and BMAT was measured by applying PRESS sequences on the L3 body. Lumbar spine, femoral neck, and total hip BMD were measured by dual x-ray absorptiometry (DXA); site-matched spine trabecular bone score (TBS) was calculated by TBS iNsight (Medimaps, Switzerland); VF assessment was performed with lateral thoracic and lumbar spine DXA. Fat content (FC) and saturation level (SL%) were higher (P <.0001 and P <.001), while water content (W) was lower in HypoPT compared to controls (P <.0001). FC significantly correlated with years since menopause and body weight (P <.05) in HypoPT, while TBS negatively correlated with FC and SL% (P <.05) and positively with residual lipids (RL) and W (P <.05). We demonstrate for the first time that BMAT is increased in postmenopausal women with postsurgical hypoparathyroidism and negatively associated with trabecular microarchitecture.

Bone health evaluation in primary hyperparathyroidism using dual-energy X-ray absorptiometry and trabecular bone score.

Bone involvement in primary hyperparathyroidism (PHPT) is characterized by reduced bone mineral density (BMD) using dual X-ray absorptiometry (DXA). A hallmark of PHPT is BMD loss at cortical sites while trabecular bone remains relatively preserved. PHPT is associated with increased fracture risk at both trabecular and cortical skeletal sites, which cannot be explained based on BMD values alone. The application of the trabecular bone score (TBS), an index of the lumbar spine DXA bone microarchitecture, showed lower TBS values and increased risk of fractures in PHPT patients, independent of BMD. Although further prospective studies are needed, promising data have been published with the use of TBS and some advanced DXA-based imaging modalities in patients with PHPT.

Changes in body composition in the year following critical illness: A case-control study.

To measure changes in dual x-ray absorptiometry (DXA) derived body composition in Intensive Care Unit (ICU) survivors in the year following discharge and compare to population controls. Using prospective observational data changes in hip and spine DXA estimated lean and fat mass between ICU discharge and 1-year follow-up were calculated and compared with age-sex-height matched controls from the Geelong Osteoporosis Study via multivariable linear regression. Sixty-four participants were included, with median age 68.8 yr [IQR 60.8, 74.6], ICU length of stay 6.5 d [IQR 4, 9] and duration of mechanical ventilation 87 h [IQR 47, 143]. ICU survivors demonstrated greater annual increases in lean (+0.92 kg; 95%CI 0.67 to 1.18, p < 0.01) and fat mass (+2.50 kg, 95%CI 1.94 to 3.05; p < 0.01) than controls. At 1-yr follow-up, the ICU group had lower lean mass (-0.96 kg, 95%CI -1.91 to -0.01; p = 0.047) and greater fat mass (6.79 kg, 95%CI 4.55 to 9.03; p < 0.001). Mechanically ventilated adult ICU patients gained lean mass in the year following critical illness but did not reach the level of matched population-based peers. Understanding the factors associated with, and effect of increasing muscle mass and reducing fat mass in the year after critical illness requires further investigation.

The Usefulness of Trabecular CT Attenuation Measurement at L4 Level to Predict Screw Loosening After Degenerative Lumbar Fusion Surgery: Consider Number of Fused Levels and Postoperative Sagittal Balance.

Retrospective study. To evaluate the absolute value of L4 trabecular region-of-interest (t-ROI) computed tomography (CT) attenuation, which can predict pedicle screw loosening, and determine the changes in value according to number of fused levels and sagittal balance in patients undergoing lumbar fusion surgery. Although osteoporosis was not diagnosed in spinal dual x-ray absorptiometry preoperatively, we encountered several cases of screw loosening within 1 year of lumbar fusion surgery. We enrolled 478 patients and analyzed factors related to screw loosening. We evaluated the association between L4 t-ROI CT attenuation and screw loosening and determined the best cutoff value of t L4 t-ROI CT attenuation for predicting screw loosening. The number of fused levels, postoperative C7-S1 sagittal vertical axis (SVA), and L4 t-ROI CT attenuation were independently correlated with screw loosening. According to number of fused level and postoperative C7-T1 SVA (≥36.9 mm or <36.9 mm), in patients with one-level fusion and C7-S1 SVA less than 36.9 mm, the optimal cutoff point of the L4 t-ROI CT attenuation predicting screw loosening was 106.5 Hounsfield unit (HU). L4 t-ROI attenuation did not change until two-level fusions. In patients with three-level fusions and C7-S1 SVA less than 36.9 mm, the optimal cutoff point of the L4 t-ROI CT attenuation predicting screw loosening was 159.0 HU. The optimal cutoff point of L4 t-ROI CT attenuation in patients with three-level fusions and C7-S1 SVA more than or equal to 36.9 mm was 191.0 HU. L4 t-ROI CT attenuation value considering number of fused levels and sagittal balance is an accurate measurement method to predict screw loosening. Spine surgeons should be aware of the L4 t-ROI attenuation before surgery to improve the fusion rate and reduce instrument-related complications of lumbar spine surgery in osteoporotic patients. 3.

Beyond bone mineral density: new developments in dual X-ray absorptiometry assessment of bone quality

Bone mineral density, bone texture, bone geometry and bone strength are all elements necessary for a proper osteoporotic fragility fracture prediction assessment. Data regarding bone quantity (density) and, in part, bone quality (structure and geometry) are obtained by the gold standard method of dual X-ray absorptiometry (DXA), while data about bone strength are obtained by means of a new DXA index called the bone strain index (BSI). The BSI evaluates bone resistance by means of average strain calculation, and it is based on finite element analysis applied to DXA spine and femoral scans. The BSI includes local information on bone density distribution, bone geometry and, unlike variables of bone mineral density and bone quality such as the trabecular bone score, it represents the status of the bone in a particular loading condition. This review illustrates the methodology for calculating the BSI and discusses findings on its reproducibility and data about its capability to predict fragility fractures and monitor pharmacological treatment for osteoporosis.

Estimation of Whole-Body and Appendicular Lean Mass from Spine and Hip Dual Energy X-ray Absorptiometry: A Cross-Sectional Study.

Whole-body dual X-ray absorptiometry (DXA) accurately measures lean mass but is not routinely used in clinical practice. Hip and spine DXA are used in the diagnosis of osteoporosis, and with the common co-occurrence of sarcopenia with osteoporosis, regional DXA scans provide an opportunity for assessment of lean mass. The aim of this study is to develop predictive equations for the estimation of whole-body lean mass (WBLM), appendicular lean mass (ALM) and whole-body fat mass (WBFM) from regional DXA scans. A total of 2427 participants (ages 20-96year; 57.7% men) from the Geelong Osteoporosis Study who underwent both regional and whole-body DXA were included in the analysis. Using forward stepwise multivariable linear regression, percentage fat (spine%fat, hip%fat) values from lumbar spine and femoral neck DXA were used in combination with clinical data to develop and validate equations for the estimation of WBLM, WBFM and ALM. Mean age was 53.5year (± 19.2), weight 78.2kg (± 15.4), height 169.6cm (± 9.4), WBLM 50.4kg (± 11.1), ALM 22.8kg (± 5.4) and WBFM 24.3kg (± 10.4). Spine%fat (r = 0.21) and hip%fat (r = - 0.34) were correlated with whole-body lean mass (p < 0.001). Final predictive equations included age, sex, weight, height, spine%fat, and hip%fat and possessed high predictive value (Adj R2 0.91-0.94, RMSE 1.60-2.84kg). K-fold cross-validation methods produced median root mean square error (RMSE) ranging from 1.59 to 2.81kg for the three models. Regional DXA scans of the spine and hip can be used to estimate whole-body and appendicular lean mass, to assist in the identification of low muscle mass.

Fracture Risk Assessment: An Update.

Our ability to accurately identify high fracture risk in individuals has improved as the volume of clinical data has expanded and fracture risk assessment tools have been developed. Given its accessibility, affordability, and low radiation exposure, dual x-ray absorptiometry (DXA) remains the standard for osteoporosis screening and monitoring response to treatment. The trabecular bone score (TBS) is a DXA software add-on that uses lumbar spine DXA imaging to produce an output that correlates with bone microarchitecture. It has been identified as an independent fracture risk factor and may prove useful in further stratifying fracture risk among those with a bone mineral density (BMD) in the osteopenic range (-1.0 to -2.4 standard deviations), in those with low-energy fractures but normal or only mildly low BMD, or in those with conditions known to impair bone microarchitecture. Fracture risk assessment tools, including the Fracture Risk Assessment Tool (FRAX), Garvan fracture risk calculator, and QFracture, evaluate the impact of multiple clinical factors on fracture risk, even in the absence of BMD data. Each produces an absolute fracture risk output over a defined interval of time. When used appropriately, these enhance our ability to identify high-risk patients and allow us to differentiate fracture risk among patients who present with similar BMDs. For challenging clinical cases, a combined approach is likely to improve accuracy in the identification of high-risk patients who would benefit from the available osteoporosis therapies.

Does Quantitative Ultrasound at the Calcaneus Predict an Osteoporosis Diagnosis in Postmenopausal Women from the Silesia Osteo Active Study?

The aims of the study were to assess the clinical conformity between quantitative ultrasound (QUS) and densitometry with use of the standard World Health Organization T-score thresholds to determine optimal diagnostic cutoff values for QUS T-scores in different age groups. Three hundred sixty-five postmenopausal Caucasian women were enrolled into the study and divided into two age groups (<65 y and ≥65 y). Skeletal status was assessed using QUS measurements at the calcaneus and bone densitometry at the spine and proximal femur (Hologic Explorer, Bedford, MA, USA). QUS measurement results expressed as the stiffness index (SI) correlated significantly with both femoral neck bone mineral density (r = 0.51, p < 0.0001) and lumbar spine bone mineral density (r = 0.52, p < 0.0001). On the basis of receiver operating characteristic curve analyses, the thresholds for correspondence between QUS T-score values and T-score –2.5SD in dual X-ray absorptiometry (DXA) were established. They ranged between –1.63SD and –1.70SD in relation to femoral neck DXA and between –1.22SD and –1.51SD in relation to lumbar spine DXA, depending on age category. In conclusion, the study described here confirmed that QUS measurements at the calcaneus may provide information comparable to DXA examinations at the femoral neck and lumbar spine in postmenopausal women.

Usefulness of Trabecular CT Attenuation Measurement of Lumbar Spine in Predicting Osteoporotic Compression Fracture: Is the L4 Trabecular Region of Interest Most Relevant?

Retrospective study. The aim of this study was to evaluate the usefulness of computed tomography (CT) attenuation in defining trabecular region-of-interest (t-ROI) at lumbar vertebral body in the assessment of osteoporotic compression fracture (OCF) compared to spinal dual x-ray absorptiometry (DXA). Even though osteoporosis was not diagnosed in the bone mineral density measurement using DXA, we often experienced cases where the screw was weakly inserted due to low bone quality during screw insertion. A total of 188 patients who met the inclusion criteria were enrolled. We determined best cutoff value of the simple t-ROI attenuation at the most relevant level for predicting OCF. We assessed correlations between the simple t-ROI attenuation at the most relevant level and OCF rate, and investigate the association between the number of compression fracture and simple t-ROI attenuation at the most relevant level. L4 ROI attenuation is the most accurate measurement for predicting osteoporotic compression fracture with an area under the curve of 0.798. The optimal cutoff point of L4 ROI attenuation was measured at 90.5 HU with 88.8% and 60.6% sensitivity and specificity, respectively. L4 ROI attenuation was significantly correlated with the osteoporotic compression fracture rate (r = -0.545, P < 0.001). The number of compression fracture (coefficient of determination R2 = 0.286; P < 0.001) was independently correlated with L4 ROI attenuation. Simple t-ROI computed tomography attenuation is an accurate measurement tool in predicting OCF compared to DXA T-score. The value of L4 t-ROI attenuation is the most relevant measurement for predicting osteoporotic compression fracture, is an alternative to DXA, and can predict the number and rate of compression fractures. Spine surgeons should be aware of L4 t-ROI attenuation to make successful fusion in spine surgery for elderly patients group.Level of Evidence: 3.

Bone mineral density and fracture risk in adult patients with hypophosphatasia

SummaryIn adult hypophosphatasia (HPP) patients, elevated lumbar spine dual X-ray absorptiometry (DXA) values are associated with markers of disease severity and disease-specific fracture risk while femoral bone mineral density (BMD), being largely unaffected by the disease severity, may still be useful to monitor other causes of increased fracture risk due to low BMD.IntroductionHypophosphatasia (HPP) is a rare inherited metabolic disorder due to deficient activity of the tissue-nonspecific alkaline phosphatase (TNAP). Clinical manifestation in adult HPP patients is manifold including an increased risk for fractures, but data regarding clinical significance of DXA measurement and associations with fracture risk and disease severity is scarce.MethodsRetrospective single-center analysis of DXA scans in patients with confirmed HPP (documented mutation, clinical symptoms, low alkaline phosphatase activity). Further data evaluation included disease-related fractures, laboratory results (alkaline phosphatase, pyridoxalphosphate, phosphoethanolamine), and medical history.ResultsAnalysis included 110 patients (84 female, mean age of 46.2 years) of whom 37.3% (n = 41) were harboring two mutations. Average T-Score level at the lumbar spine was − 0.1 (SD 1.9), and mean total hip T-Score was − 1.07 (SD 0.15). Both lower ALP activity and higher substrate levels (pyridoxalphosphate and phosphoethanolamine) were significantly correlated with increased lumbar spine T-Score levels (p < 0.001) while BMD at the hip was not affected by indicators of disease severity. Increased lumbar spine BMD was significantly associated with an increased risk for HPP-related fractures, prevalent in 22 (20%) patients (p < 0.001) with 21 of them having biallelic mutations.ConclusionBMD in adult HPP patients is not systematically reduced. Conversely, increased lumbar spine BMD appears to be associated with severely compromised mineralization and increased risk for HPP-related fractures while BMD at the hip appears unaffected by indicators of disease severity, suggesting suitability of this anatomic location for assessing and discerning disorders with increased fracture risk owing to reduced BMD like osteoporosis.Trial registration numberGerman register for clinical studies (DRKS00014022)Date of registration02/10/2018 – retrospectively registered

Trabecular Bone Score (TBS) Predicts Fracture in Ankylosing Spondylitis: The Manitoba BMD Registry

Introduction: Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine characterized among other features by spinal boney proliferation, back pain, loss of flexibility, and increased fracture risk. Overlying bone limits the utility of bone mineral density (BMD) by dual X-ray absorptiometry (DXA) in the spine. Trabecular bone score (TBS) is a bone texture measurement derived from the spine DXA image that indicates bone quality and fracture risk independent of BMD. Methodology: Using the Manitoba Bone Density Program database, patients with diagnosis codes for ankylosing spondylitis, baseline DXA and lumbar spine TBS were identified. Incident nontraumatic fractures (major osteoporotic [MOF], clinical spine, hip, and all fracture) were identified from population based databases. Cox-proportional hazard models are presented. Results: We identified 188 patients with diagnosed AS. TBS was lower in those with incident MOF (1.278 ± 0.126, compared to 1.178 ± 0.136, p < 0.001). Unadjusted TBS and FRAX-MOF-BMD adjusted predicted major osteoporotic fracture (N = 19) (hazard ratio [HR] 2.04, 95% confidence interval [CI]: 1.28–2.26, p = 0.003; HR 1.81, 95% CI: 1.11–2.96, p = 0.018). TBS unadjusted and FRAX-MOF-BMD adjusted also predicted clinical spine fracture (N = 7) (HR 2.50, 95% CI: 1.17–5.37; p = 0.019; HR 2.40 95% CI: 1.1–5.25; p = 0.028). Higher HRs were observed for prediction of hip fracture (N = 6), but these did not achieve statistical significance (FRAX-adjusted HR 1.74, 95% 0.73–4.17; p = 0.211). Unadjusted models show TBS was predictive of all fracture (N = 27) (HR 1.60, 95% CI: 1.08–2.39; p = 0.020), which was borderline significant after adjustment for FRAX-MOF-BMD (HR 1.51, 95% CI: 1.00–2.29; p = 0.052). Conclusion: We report the first analysis of TBS for fracture prediction as an incident event in AS. TBS independently predicted major osteoporotic and clinical spine fracture in AS independent of FRAX.

Pathophysiology of growth hormone secretion disorders and their impact on bone microstructure as measured by trabecular bone score.

This article is focused on endocrine-mediated osteoporosis caused by growth hormone (GH) disorders; adult GH deficiency and acromegaly. GH and insulin like growth factor-1 (IGF-1) stimulate linear bone growth through complex hormonal interactions and activates epiphyseal prechondrocytes. GH, via receptor activator of nuclear factor-kappaB (RANK), its ligand (RANK-L), and the osteoprotegerin system, stimulates production of osteoprotegerin and its accumulation in bone matrix. Malfunction of this mechanism, could lead to specific bone impairment. However, the primary problem of bone disease in GH secretion disorders is the primary prevention of osteoporotic fractures, so it is important to determine bone quality that better reflects the patient's actual predisposition to fracture. A method estimating bone quality from lumbar spine dual X-ray absorptiometry (DXA) scans is trabecular bone score (TBS). TBS in addition to bone mineral density (BMD) is a promising predictor of the osteoporotic fracture risk in women with postmenopausal osteopenia. In acromegaly TBS better defines risk of fracture because BMD is normal or even increased. TBS helps to monitor the effect of growth hormone therapy. Despite these findings, TBS should not be used alone, but a comprehensive consideration of all fracture risk factors, BMD and bone turnover markers is necessary.

Trabecular bone quality is lower in adults with type 1 diabetes and is negatively associated with insulin resistance.

We evaluated TBS, a non-invasive method to evaluate trabecular bone quality at the lumbar spine, in adults with T1D compared to age-, sex-, and BMI-matched adults without diabetes. We calculated TBS from adults with T1D (n = 47) and controls (n = 47) who had a lumbar spine dual x-ray absorptiometry (DXA) at their third visit (2006-2009) of the ongoing "Coronary Artery Calcification in Type 1 Diabetes (CACTI) Study." The linear relationships of TBS and bone mineral density (BMD) with hemoglobin A1c, blood pressure, lipids, and insulin resistance were evaluated using Pearson's correlation coefficient. Multiple linear regression was used to test the association of TBS with sex and diabetes while adjusting for other potential confounders. TBS was significantly lower in adults with T1D compared to controls (1.42 ± 0.12 vs 1.44 ± 0.08, p = 0.02) after adjusting for age, sex, current smoking status, and lumbar spine BMD, despite no difference in lumbar spine BMD between the groups. Components of the metabolic syndrome, including diastolic blood pressure, BMI, triglycerides, and insulin resistance were negatively correlated with TBS among patients with T1D. Trabecular bone score, an indirect measurement of trabecular bone quality, was lower in adults with T1D compared to controls. Components of metabolic syndrome and insulin resistance were associated with lower TBS in adults with T1D.

Is Trabecular Bone Score Valuable in Bone Microstructure Assessment after Gastric Bypass in Women with Morbid Obesity?

Introduction: The effects of bariatric surgery on skeletal health raise many concerns. Trabecular bone score (TBS) is obtained through the analysis of lumbar spine dual X-ray absorptiometry (DXA) images and allows an indirect assessment of skeletal microarchitecture (MA). The aim of our study was to evaluate the changes in bone mineral density (BMD) and alterations in bone microarchitecture assessed by TBS in morbidly obese women undergoing Roux-en-Y gastric bypass (RYGB), over a three-year follow-up. Material/Methods: A prospective study of 38 morbidly obese white women, aged 46.3 ± 8.2 years, undergoing RYGB was conducted. Biochemical analyses and DXA scans with TBS evaluation were performed before and at one year and three years after surgery. Results: Patients showed normal calcium and phosphorus plasma concentrations throughout the study. However, 25-hydroxyvitamin D (25(OH)D3) decreased, and 71% of patients had a vitamin D deficiency at three years. BMD at femoral neck and lumbar spine (LSBMD) significantly decreased 13.53 ± 5.42% and 6.03 ± 6.79%, respectively, during the three-year follow-up; however Z-score values remained above those for women of the same age. TBS was within normal ranges at one and three years (1.431 ± 106 and 1.413 ± 85, respectively), and at the end of the study, 73.7% of patients had normal bone MA. TBS at three years correlated inversely with age (r = −0.41, p = 0.010), body fat (r = −0.465, p = 0.004) and greater body fat deposited in trunk (r = −0.48, p = 0.004), and positively with LSBMD (r = 0.433, p = 0.007), fat mass loss (r = 0.438, p = 0.007) and lean mass loss (r = 0.432, p = 0.008). In the regression analysis, TBS remained associated with body fat (β = −0.625, p = 0.031; R2 = 0.47). The fracture risk, calculated by FRAX® (University of Sheffield, Sheffield, UK), with and without adjustment by TBS, was low. Conclusion: Women undergoing RYGB in the mid-term have a preserved bone MA, assessed by TBS.

Abaloparatide-SC improves trabecular microarchitecture as assessed by trabecular bone score (TBS): a 24-week randomized clinical trial

SummaryIn a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to one of three different doses of abaloparatide-SC, subcutaneous teriparatide, or placebo for 24 weeks, abaloparatide-SC resulted in improvements in skeletal microarchitecture as measured by the trabecular bone score.IntroductionSubcutaneous abaloparatide (abaloparatide-SC) increases total hip and lumbar spine bone mineral density and reduces vertebral and non-vertebral fractures. In this study, we analyzed the extent to which abaloparatide-SC improves skeletal microarchitecture, assessed indirectly by trabecular bone score (TBS).MethodsThis is a post hoc analysis of a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to abaloparatide-SC (20, 40, or 80 μg), subcutaneous teriparatide (20 μg), or placebo for 24 weeks. TBS was measured from lumbar spine dual X-ray absorptiometry (DXA) images in 138 women for whom the DXA device was TBS software compatible. Assessments were made at baseline, 12 and 24 weeks. Between-group differences were assessed by generalized estimating equations adjusted for relevant baseline characteristics, and a pre-determined least significant change analysis was performed.ResultsAfter 24 weeks, TBS increased significantly by 2.27, 3.14, and 4.21% versus baseline in participants on 20, 40, and 80 μg abaloparatide-SC daily, respectively, and by 2.21% in those on teriparatide (p < 0.05 for each). The TBS in the placebo group declined by 1.08%. The TBS increase in each treatment group was significantly higher than placebo at 24 weeks (p < 0.0001 for each) after adjustment for age, BMI, and baseline TBS. A dose-response was observed at 24 weeks across the three doses of abaloparatide-SC and placebo (p = 0.02). The increase in TBS in the abaloparatide-SC 80 μg group was significantly greater than TPTD (p < 0.03).ConclusionsThese results are consistent with an effect of abaloparatide-SC to improve lumbar spine skeletal microarchitecture, as assessed by TBS.

Habitual levels of higher, but not medium or low, impact physical activity are positively related to lower limb bone strength in older women: findings from a population-based study using accelerometers to classify impact magnitude

SummaryThis study assessed the effect of accelerometry-measured higher impacts resulting from habitual weight-bearing activity on lower limb bone strength in older women. Despite higher impacts being experienced rarely in this population-based cohort, positive associations were observed between higher vertical impacts and lower limb bone size and strength.IntroductionWe investigated whether the benefit of habitual weight-bearing physical activity (PA) for lower limb bone strength in older women is explained by exposure to higher impacts, as previously suggested by observations in younger individuals.MethodsFour hundred and eight women from the Cohort for Skeletal Health in Bristol and Avon (COSHIBA), mean 76.8 years, wore tri-axial accelerometers at the waist for a mean of 5.4 days. Y-axis peaks were categorised, using previously identified cutoffs, as low (0.5–1.0 g), medium (1.0–1.5 g), and higher (≥1.5 g) impacts. Mid and distal peripheral quantitative computed tomography scans of the tibia and radius were performed, as were hip and lumbar spine Dual X-ray Absorptiometry (DXA) scans. Regressions between (log transformed) number of low, medium and high impacts, and bone outcomes were adjusted for artefact error grade, age, height, fat and lean mass and impacts in other bands.ResultsEight thousand eight hundred and nine (4047, 16,882) low impacts were observed during the measurement week, 345 (99, 764) medium impacts and 42 (17, 106) higher impacts (median with 25th and 75th quartiles). Higher vertical impacts were positively associated with lower limb bone strength as reflected by cross-sectional moment of inertia (CSMI) of the tibia [0.042 (0.012, 0.072) p = 0.01] and hip [0.067 (0.001, 0.133) p = 0.045] (beta coefficients show standard deviations change per doubling in impacts, with 95 % confidence interval). Higher impacts were positively associated with tibial periosteal circumference (PC) [0.015 (0.003, 0.027) p = 0.02], but unrelated to hip BMD. Equivalent positive associations were not seen for low or medium impacts.ConclusionsDespite their rarity, habitual levels of higher impacts were positively associated with lower limb bone size and strength, whereas equivalent relationships were not seen for low or medium impacts.

A quantitative ultrasound approach to estimate bone fragility: A first comparison with dual X-ray absorptiometry

Abstract Aim of this paper was to assess the discrimination power of a novel ultrasound (US) parameter, called the Fragility Score (F.S.), in the early identification of subjects prone to osteoporotic fractures. A total of 102 female patients were recruited: 49 with a recent osteoporotic fracture (“frail” subjects), 53 were controls without fracture history (“non-frail” subjects). All the patients underwent a spinal DXA (dual X-ray absorptiometry) and an abdominal US scan of lumbar vertebrae. Acquired US data were analyzed by a novel algorithm, which calculated the F.S. through spectral and statistical analyses involving both echographic images and corresponding “raw” signals. F.S. showed a good performance in discriminating “frail” from “non-frail” subjects (sensitivity = 76%, specificity = 68%), resulting even slightly more effective than DXA-measured BMD (sensitivity = 73%, specificity = 66%). This methodology has a potential to become an effective tool for the early identification, and timely treatment, of “frail” subjects.