Dual-energy X-ray Absorptiometry Measurements Research Articles

Body Composition by CT vs. DXA: Long-Term Prediction of Mortality in the Health Health ABC Cohort

Background: Early work in the Health ABC cohort found that strength, but not muscle size predicted mortality. Recent literature suggests that body composition by computerized tomography (CT) and magnetic resonance imaging (MRI) predicts adverse health outcomes in diverse populations, but has not been directly compared to dual-energy X-ray absorptiometry (DXA) for predicting mortality. Objective: With long term follow-up, we reexamined body composition and mortality in Health ABC, comparing DXA and CT measures of muscle and fat. Methods: The Health ABC study assessed body composition in 2911 older adults (age 73.6±2.9 years) in 1996-97. Mid-thigh CTs were read for muscle area, inter-muscular, subcutaneous-fat areas and muscle density (HU). DXAs were read for whole body fat mass and appendicular lean mass (ALM). Mortality was assessed every 6-months through 2014 (maximum 17.4 years). Cox proportional hazards models, adjusting for age, sex, race, height, weight, physical activity, smoking and comorbidities were used to assess mortality risk. Results: Strong correlations were observed between mid-thigh muscle and subcutaneous fat areas by CT and leg lean and fat mass by DXA (P<0.05). Lower mortality rates, per SD, were associated with higher CT muscle area (HR-men=0.76 [95%CI: 0.68-0.86]; HR-women=0.84 [0.75-0.94]), muscle density (HR-men=0.86 [0.79-0.93]; HR-women=0.89 [0.81-0.97]) and higher subcutaneous-fat (HR-men=0.90 [0.81-0.99]; HR-women=0.87 [0.77-0.98]), adjusting for covariates. Similarly for DXA, greater ALM (HR-men=0.56 [0.44-0.71]; HR-women=0.77 [0.59-1.01]) and higher total fat mass (HR-men=0.53 [0.40-0.72]; HR-women=0.58 [0.37-0.90]) were associated with lower risk of death. Conclusion: With long term follow-up, both CT and DXA assessments of body composition predicted all-cause mortality risk.

Lower Trabecular Bone Score and Spine Bone Mineral Density Are Associated With Bone Stress Injuries and Triad Risk Factors in Collegiate Athletes.

Determinants of bone health and injury are important to identify in athletes. Bone mineral density (BMD) is commonly measured in athletes with Female Athlete Triad (Triad) risk factors; the trabecular bone score (TBS) has been proposed to predict fracture risk independent of BMD. Evaluation of TBS and spine BMD in relation bone stress injury (BSI) risk has not been studied in female collegiate athletes. We hypothesized that spine BMD and TBS would each independently predict BSI and that the combined measures would improve injury prediction in female collegiate athletes. We also hypothesized that each measure would be correlated with Triad risk factors. Retrospective cohort. Academic Institution. Dual energy x-ray absorptiometry (DXA) of the lumbar spine was used to calculate BMD and TBS values. Chart review was used to identify BSI that occurred after the DXA measurement and to obtain Triad risk factors. We used logistic regression to examine the ability of TBS and BMD alone or in combination to predict prospective BSI. Within 321 athletes, 29 (9.0%) sustained a BSI after DXA. BMD and TBS were highly correlated (Pearson correlation r = 0.62, P < .0001). Spine BMD and TBS had similar ability to predict BSI; the C-statistic and 95% confidence intervals were 0.69 (0.58 to 0.81) for spine BMD versus 0.68 (0.57 to 0.79) for TBS. No improvement in discrimination was observed with combined BMD + TBS (C-statistic 0.70, 0.59 to 0.81). Both TBS and BMD predicted trabecular-rich BSI (defined as pelvis, femoral neck, and calcaneus) better than cortical-rich BSI. Both measures had similar correlations with Triad risk factors. Lower BMD and TBS values are associated with elevated risk for BSI and similar correlation to Triad risk factors. TBS does not improve prediction of BSI. Collectively, our findings suggest that BMD may be a sufficient measure of skeletal integrity from DXA in female collegiate athletes.

Age-related changes in appendicular lean mass in males with Duchenne muscular dystrophy: A retrospective review.

Appendicular lean mass (ALM) trajectory in males with Duchenne muscular dystrophy (DMD) has potential applicability for treatment and research and has not been characterized. This chart review included longitudinal data on 499 males with DMD receiving glucocorticoids and 693 controls, ages 5 to 22.9 y. ALM (kg) was measured by dual energy x-ray absorptiometry (DXA). Appendicular lean mass index (ALMI, kg/m2 ) was calculated for height adjustment. Reference centiles were generated using data from healthy controls, and ALM and ALMI Z-scores were calculated for patients with DMD. Generalized linear models were used to estimate median Z-scores by age and functional mobility status (FMS) score. ALM velocity by age was modeled using superimposition, translation and rotation (SITAR). Compared to controls, males with DMD had lower ALM from an early age. ALMI Z-scores dropped below 0 at age 8 y or FMS of 2, and below -2.0 at age 13 y or FMS of 3 (P < .05). Age at peak ALM velocity was similar in both groups, but the magnitude was higher in controls (3.5 vs. 0.7 kg/y, P < .0001). Patients with DMD had a transient loss of ALM around age 12 y, an increase at age 14 y, then a further decline at age 16 y, remaining low thereafter. Males with DMD have progressive decline in lean mass with age and worsening functional mobility. DXA measurement of ALM may be useful for monitoring lean mass status in patients with DMD, providing valuable information for individual treatment plans and research endeavors.

Differentiation of Traumatic Osteoporotic and Non-Osteoporotic Vertebral AO A3 Fractures by Analyzing the Posterior Edge Morphology-A Retrospective Feasibility Study.

Background: Differentiation between traumatic osteoporotic and non-osteoporotic vertebral fractures is crucial for optimal therapy planning. We postulated that the morphology of the posterior edge of the cranial fragment of A3 vertebral fractures is different in these entities. Therefore, the purpose of this study is to develop and validate a simple method to differentiate between osteoporotic and non-osteoporotic A3 vertebral fractures by morphological analysis. Methods: A total of 86 computer tomography scans of AO Type A3 (cranial burst) vertebral body fractures (52 non-osteoporotic, 34 osteoporotic) were included in this retrospective study. Posterior edge morphology was analyzed using the sagittal paramedian slice with the most prominent shaped bulging. Later, the degree of bulging of the posterior edge fragment was quantified using a geometric approach. Additionally, the Hounsfield units of the broken vertebral body, the vertebra above, and the vertebra below the fracture were measured. Results: We found significant differences in the extent of bulging comparing osteoporotic and non-osteoporotic fractures in our cohort. Using the presented method, sensitivity was 100%, specificity was 96%. The positive predictive value (PPV) was 94%. In contrast, by evaluating the Hounsfield units, sensitivity was 94%, specificity 94% and the PPV was 91%. Conclusions: Our method of analysis of the bulging of the dorsal edge fragment in traumatic cranial burst fractures cases allows, in our cases, a simple and valid differentiation between osteoporotic and non-osteoporotic fractures. Further validation in a larger sample, including dual-energy X-ray absorptiometry (DXA) measurements, is necessary.

Differences in Femoral Neck and Trochanteric Structure in Elderly Women Prior to Hip Fracture: Role in Hip Fracture Prediction.

We examine the hypothesis that internal dual-energy X-ray absorptiometry (DXA) structural variables measured at the femoral neck and trochanter cross sections will improve prediction of fractures at these sites in addition to areal BMD (aBMD). We present an analysis of the internal distribution of bone at the site of these fractures using baseline hip DXA measurement of 1151 participants, mean age (SD) 75 (3) years, in the 14.5-year Perth Longitudinal Study of Aging in Women. Structural differences at the femoral neck (FN) and trochanter (TR) cross sections were compared in 69 participants who went on to sustain femoral neck fracture (FNF) and 59 participants who went on to sustain trochanter fracture (TRF), on average 10 years later, to those who did not fracture. The new structural variables, in addition to aBMD and bone width (W), were Sigma (distribution of bone within scanned area) and Delta (distance between center-of-mineral mass and geometric center), which can be assessed by current DXA programs. At baseline, compared with nonfracture cases, FNF cases had a FNaBMD 7% lower, a FNWidth 3% higher and a FNDelta 29% higher, associated with reduced bone in the superior segment. In FNF Cox proportional hazard analysis, age (hazard ratio [HR 1.39]), total hip aBMD (THaBMD; 0.79), and Delta (1.70) were significant. Addition of FN Delta to the base case of THaBMD and age improved the C statistic from 0.62 to 0.69, p = 0.01. At baseline, TRF cases had a 15% lower TRaBMD with minor differences in Sigma (1%) and Width (2%). In TRF Cox analysis, neither addition of Sigma nor Width improved the model that included age and THaBMD as predictors and did not alter the C-statistic of 0.81. In conclusion, adding measurement of FN Delta, an assessment of superior sector bone loss, to hip aBMD and age substantially improved clinical FNF prediction in older women. © 2023 American Society for Bone and Mineral Research (ASBMR).

2+2 (+ 2)=4: A new approach for appendicular muscle mass assessment by ultrasound.

The aim of this study was to develop new appendicular lean mass (ALM) prediction models based on ultrasound and anthropometric measurements. This was a cross-sectional assessment of a subsample from a population-based study (COMO VAI?), conducted with community-dwelling individuals ≥60 y of age living in a southern Brazilian city. ALM was measured by dual-energy x-ray absorptiometry (DXA). Muscle thickness (MT) from supine participants was assessed by ultrasound on the anterior aspect of both upper and lower limbs. Such measures, along with anthropometric data, were used to develop prediction models (multivariable linear regression) through the backward stepwise method. The study included 190 participants composed mainly of women, white, and middle-class individuals. The best ALM predictive performance was achieved by a model based on two "lengths" (height and arm length), two circumferences (dominant arm and thigh), and two ultrasound-measured MTs (dominant arm and thigh): R2=0.90, limits of agreement: ±2.36 kg. Closely satisfactory results were also achieved by an "abbreviated" model composed by the two aforementioned "lengths" and MTs (R2=0.89, limits of agreement: ±2.51 kg). ALM estimates from both equations were unbiased and similar to DXA measurements (P = 0.13 and 0.09, respectively). Bootstrap analysis favorably suggested the validity of the models. Based on two ultrasound assessments and a few anthropometric measurements, the developed equations produced accurate and unbiased ALM estimates in the sample. Hence: 2 MTs+2 lengths (+ 2 circumferences)=4 limbs' muscle mass. Such models might represent promising alternatives for muscle assessment among older individuals.

Differences in sarcopenia prevalence between upper-body and lower-body based EWGSOP2 muscle strength criteria: the Troms\xf8 study 2015\u20132016

BackgroundThe European Working Group on Sarcopenia in Older People (EWGSOP2) recommends grip strength and chair stand tests to be used as primary defining measures. It is unclear how either test affects prevalence estimates.MethodsThis cross-sectional study involved 3498 community-dwelling participants (40–84 years) from the 7th Tromsø Study survey (2015–2016). We used grip strength, five-repetition chair stands, four-meter Walk Speed Test, Timed-Up-and-Go (TUG) and Dual-Energy X-ray Absorptiometry measurements. Data were analyzed using multiple linear regression models and ROC-curves.ResultsProbable and confirmed sarcopenia prevalence was 1.3 and 4.4% based on grip strength and chair stands, respectively. There was very low agreement between grip strength and chair stand cut-offs (κ = 0.07), with only 4.3% of participants defined as having probable sarcopenia overlapping in the two criteria. Participants with grip strength-based sarcopenia had lower mean height, weight, waist circumference, and appendicular lean mass relative to body height (ALMheight2) than non-sarcopenic participants (all p < 0.001), after adjusting for multiple covariates. Conversely, participants with chair stand-based sarcopenia had similar height, higher weight, waist circumference and body fat% compared to non-sarcopenic participants (all p < 0.05). Area-under-curves (AUCs) for TUG-time were significantly larger when using chair stand instead of grip strength cut-offs (0.86, 95% CI 0.84–0.89 vs. 0.75, 95% CI 0.69–0.83).ConclusionsUsing chair stands instead of grip strength more than doubled probable sarcopenia prevalence across all ages. The two measures defined individuals of contradictory anthropometrics, body composition, and dissimilar physical function to have probable sarcopenia. Researchers should further evaluate the consequences of using different strength measures in the EWGSOP2 definition to classify sarcopenia.

Opportunistic QCT Bone Mineral Density Measurements Predicting Osteoporotic Fractures: A Use Case in a Prospective Clinical Cohort.

PurposeTo assess whether volumetric vertebral bone mineral density (BMD) measured with opportunistic quantitative computed tomography (QCT) (i.e., CT acquired for other reasons) can predict osteoporotic fracture occurrence in a prospective clinical cohort and how this performs in comparison to dual-energy X-ray absorptiometry (DXA) measurements.MethodsIn the database of our fracture liaison service, 58 patients (73 ± 11 years, 72% women) were identified that had at least one prevalent low-energy fracture and had undergone CT of the spine. BMD was determined by converting HU using scanner-specific conversion equations. Baseline DXA was available for 31 patients. During a 3-year follow-up, new fractures were diagnosed either by (i) recent in-house imaging or (ii) clinical follow-up with validated external reports. Associations were assessed using logistic regression models, and cut-off values were determined with ROC/Youden analyses.ResultsWithin 3 years, 20 of 58 patients presented new low-energy fractures (34%). Mean QCT BMD of patients with fractures was significantly lower (56 ± 20 vs. 91 ± 38 mg/cm3; p = 0.003) and age was higher (77 ± 10 vs. 71 ± 11 years; p = 0.037). QCT BMD was significantly associated with the occurrence of new fractures, and the OR for developing a new fracture during follow-up was 1.034 (95% CI, 1.010–1.058, p = 0.005), suggesting 3% higher odds for every unit of BMD decrease (1 mg/cm3). Age and sex showed no association. For the differentiation between patients with and without new fractures, ROC showed an AUC of 0.76 and a Youden’s Index of J = 0.48, suggesting an optimal cut-off value of 82 mg/cm3. DXA T-scores showed no significant association with fracture occurrence in analogous regression models.ConclusionIn this use case, opportunistic BMD measurements attained through QCT predicted fractures during a 3-year follow-up. This suggests that opportunistic measurements are useful to reduce the diagnostic gap and evaluate the fracture risk in osteoporotic patients.

Short-Term Precision Error of Bone Strain Index, a New DXA-Based Finite Element Analysis Software for Assessing Hip Strength

Bone Strain Index (BSI) is a new finite element analysis tool applied to hip dual energy X-ray absorptiometry scans. The aim of this study was to assess the short-term precision error of BSI on the proximal femur, both on a phantom and patients. The International Society for Clinical Densitometry guidelines were followed for short-term precision error assessment. Dual energy X-ray absorptiometry measurements were performed on an anthropomorphic femur phantom that was scanned twice for 30 times, for a total of 60 scans. For the in vivo part, 30 subjects were scanned twice. BSI precision error was compared to that of bone mineral density (BMD). Both for the phantom and the in vivo study BSI reproducibility was lower compared to that of BMD, as the precision error of BSI resulted 3 times higher compared to that BMD. For phantom measurements, the highest precision value was that of total femur (TF) BMD (coefficient of variation [CoV] = 0.63%, reproducibility = 98.24%), while the lowest precision was the femoral neck (FN) BSI (CoV = 3.08%, reproducibility = 91.48%). Similarly, for the in vivo study, the highest precision was found at TF BMD (CoV = 1.36%, reproducibility = 96.22%), while the lowest value of precision was found for FN BSI (CoV = 4.17%, reproducibility = 88.46%). Reproducibility at TF was always better compared to that of the FN. BSI precision error was about 3 times higher compared to BMD, confirming previous results of lumbar spine BSI. The main source of variability of this new software is related to patient positioning.

Routine serum biomarkers, but not dual-energy X-ray absorptiometry, correlate with cortical bone mineral density in children and young adults with chronic kidney disease.

Biomarkers and dual-energy X-ray absorptiometry (DXA) are thought to be poor predictors of bone mineral density (BMD). The Kidney Disease: Improving Global Outcomes guidelines suggest using DXA if the results will affect patient management, but this has not been studied in children or young adults in whom bone mineral accretion continues to 30 years of age. We studied the clinical utility of DXA and serum biomarkers against tibial cortical BMD (CortBMD) measured by peripheral quantitative computed tomography, expressed as Z-score CortBMD, which predicts fracture risk. This was a cross-sectional multicentre study in 26 patients with CKD4 and 5 and 77 on dialysis. Significant bone pain that hindered activities of daily living was present in 58%, and 10% had at least one low-trauma fracture. CortBMD and cortical mineral content Z-scores were lower in dialysis compared with CKD patients (P = 0.004 and P = 0.02). DXA BMD hip and lumbar spine Z-scores did not correlate with CortBMD or biomarkers. CortBMD was negatively associated with parathyroid hormone (PTH; r = -0.44, P < 0.0001) and alkaline phosphatase (ALP; r = -0.22, P = 0.03) and positively with calcium (Ca; r = 0.33, P = 0.001). At PTH <3 times upper limit of normal, none of the patients had a CortBMD below -2 SD (odds ratio 95% confidence interval 7.331 to infinity). On multivariable linear regression PTH (β = -0.43 , P < 0.0001), ALP (β = -0.36, P < 0.0001) and Ca (β = 0.21, P = 0.005) together predicted 57% of variability in CortBMD. DXA measures did not improve this model. Taken together, routinely used biomarkers, PTH, ALP and Ca, but not DXA, are moderate predictors of cortical BMD. DXA is not clinically useful and should not be routinely performed in children and young adults with CKD 4-5D.

Predicting 3D body shape and body composition from conventional 2D photography.

Total and regional body composition are important indicators of health and mortality risk, but their measurement is usually restricted to controlled environments in clinical settings with expensive and specialized equipment. A method that approaches the accuracy of the current gold standard method, dual-energy x-ray absorptiometry (DXA), while only requiring input from widely available consumer grade equipment, would enable the measurement of these important biometrics in the wild, enabling data collection at a scale that would have previously been prohibitive in time and expense. We describe an algorithm for predicting three-dimensional (3D) body shape and composition from a single frontal 2-dimensional image acquired with a digital consumer camera. Duplicate 3D optical scans, two-dimensional (2D) optical images, and DXA whole-body scans were available for 183 men and 233 women from the Shape Up! Adults Study. A principal component analysis vector basis was fit to 3D point clouds of a training subset of 152 men and 194 women. The relationship between this vector space and DXA-derived body composition was modeled with linear regression. The principal component 3D shape was then fitted to match a silhouette extracted from a 2D photograph of a novel body. Body composition was predicted from the resulting 3D shape match using the linear mapping between the principal component parameters and the DXA metrics. Accuracy of body composition estimates from the silhouette method was evaluated against a simple model using height and weight as a baseline, and against DXA measurements as ground truth. Test-retest precision of the silhouette method was evaluated using the duplicate 2D optical images and compared against precision of the duplicate DXA scans. Paired t-tests were performed to detect significant differences between the sets. Results were reported on a held-out set. Body composition prediction achieved R2 s of 0.81 and 0.74 for percent fat prediction of males and females, respectively, on a held-out test set consisting of 31 males and 39 females. Precision estimates for fat mass were 2.31% and 2.06% for males and females, respectively, compared to 1.26% and 0.68% for DXA scans. The t-tests revealed no statistically significant differences between the silhouette method measurements and DXA measurements, or between retests. Total and regional body composition measures can be estimated from a single frontal photograph of a human body. Body composition prediction using consumer level photography can enable early screening and monitoring of possible physiological indicators of metabolic disease in regions where medical imagery or clinical assessment is inaccessible.

IGF-1R/β-catenin signaling axis is implicated in streptozotocin exacerbating bone impairment in ovariectomized rats

Objective The aim of this study was to investigate the role of the insulin-like growth factor-1 receptor (IGF-1R)/β-catenin signaling axis in bone impairment induced by hyperglycemia in ovariectomized rats. Methods Rats were divided into four groups. The sham group received sham operation and a single intraperitoneal administration of vehicle. The ovariectomy (OVX) group was subjected to bilateral OVX and vehicle injection. The streptozotocin (STZ) group received sham operation and a single STZ injection to induce hyperglycemia. The OVX + STZ group received bilateral OVX and a single STZ injection. Dual-energy X-ray absorptiometry measurement, bone biomechanics test, micro-computed tomography scan, and hematoxylin–eosin staining were performed to evaluate bone alteration in this model. The expression of relevant signals including IGF-1R, glycogen synthase kinase-3β (GSK-3β), and β-catenin were examined by quantitative real-time polymerase chain reaction and western blot. Results The OVX, STZ, and OVX + STZ groups induced bone loss, attenuated bone strength, and impaired microarchitecture compared with the sham group, respectively. Compared with OVX, more serious bone damage was found in the OVX + STZ group, which showed enhanced phosphorylation of IGF-1R, GSK-3β, and β-catenin. Conclusion OVX plus STZ induced more serious bone impairment than OVX alone, which involves the IGF-1R/β-catenin signaling axis in the pathogenesis. This may provide a potential target for treatment of postmenopausal diabetic osteoporosis.

Human Muscle Mass Measurement through passive Flexible UWB-Myogram Antenna sensor to diagnose Sarcopenia

Sarcopenia disease is due to low muscle mass in humans. Sarcopenia leads to osteoporosis, metabolic syndrome and difficulty in performing day-to-day activities. At present, Dual-energy X-ray Absorptiometry (DXA) measures muscle mass with few limitations. They are variations in measurements according to region under investigation, irregularities in hydration status, and low precision in tall and obese persons. These limitations are due to low dosage level of X-ray radiations in certain muscle regions of human body such as heart, head, lower and upper extremities. This paper presents a non-invasive passive flexible Ultra Wide Band (UWB) Myogram antenna sensor for the prediction of Sarcopenia through human muscle mass measurement. This antenna is adhesively fixed on ventral surface of forearm and biceps for the measurement of skeletal and lean mass respectively. The proposed antenna sensor performs electromagnetic energy absorption from muscle tissues under radiating near-field condition. The muscle tissue signal from antenna is applied to blind source filtering-Non-negative Matrix Factorization (NMF), then subjected to Multi-Synchro Squeezing Transform (MSST), and finally correlated using linear regression machine learning algorithm to diagnose Sarcopenia. Furthermore, the proposed methodology is developed as a product through the MATLAB Mobile App compatible with Android devices. The proposed method of diagnosing Sarcopenia achieves an accuracy of 85% in fifty samples.

A rapid point-of-care ultrasound marker for muscle mass and muscle strength in older adults.

Background/ObjectivesSarcopenia is defined as the gradual age-associated loss of both muscle quantity and strength in older adults, and is associated with increased mortality, falls, fractures and hospitalisations. Current sarcopenia criteria use dual-energy X-ray absorptiometry (DXA) measures of muscle mass, a test that cannot be performed at the bedside, unlike point-of-care ultrasound (PoCUS). We examined the association between ultrasonic measures of muscle thickness (MT, vastus medialis muscle thickness) and measures of muscle quantity and strength in older adults.MethodsA total of 150 older adults (age ≥ 65; mean age 80.0 ± 0.5 years, 66 women, 84 men) were recruited sequentially from geriatric medicine clinics. Each subject had lean body mass (LBM, by bioimpedance assay), grip strength, mid-arm biceps circumference (MABC), gait speed and MT measured. All initial models were adjusted for biological sex.ResultsIn our final parsimonious models, MT showed a strong significant correlation with all measures of muscle mass, including LBM (Standardised β = 0.204 ± 0.058, R2 = 0.577, P < 0.001) and MABC (Standardised β = 0.141 ± 0.067, R2 = 0.417, P = 0.038). With respect to measures of muscle quality, there was a strong significant correlation with grip strength (Standardised β = 0.118 ± 0.115, R2 = 0.511, P < 0.001) but not with subject performance (gait speed).ConclusionsMT showed strong correlations with both measures of muscle mass (LBM and MABC) and with muscle strength (grip strength). Although more work needs to be done, PoCUS shows potential as a screening tool for sarcopenia in older adults.

Translation, cultural adaptation, and validation of the 10-year Fracture Risk Assessment Tool into Filipino

Introduction: Screening tools for osteoporosis are relatively expensive and inaccessible to the general Filipino population. This study aims to develop a Filipino version of a validated measure, the Fracture Risk Assessment Tool (FRAX), in order to facilitate improvement of fracture prevention care in the country. Methods: The FRAX was translated and culturally adapted into a Filipino version using established forward and backward translation methods and was succeedingly tested for equivalence to the original. The final version was administered to 120 outpatients and was tested for reliability using peripheral dual-energy x-ray absorptiometry (DXA) measurements of the distal radius. Results: To be better understood and reliably answered by the Filipino population, several qualifiers were added to items such as previous fracture and rheumatoid arthritis. This was to account for the high incidence of high-energy trauma in the country and the use of the same Filipino term for rheumatoid arthritis (RA) as with other arthritides, respectively. Conclusion: The Filipino version of the FRAX appears to be an acceptable and reliable instrument, serving as a low-cost alternative to bone mineral density (BMD) and DXA scans which are generally inaccessible and unaffordable by majority of the populations.

207. Postmenopausal women presenting for spinal fusion surgery have abnormal microarchitecture despite normal DXA

BACKGROUND CONTEXT More than 400,000 spinal fusion surgeries are performed annually in the US, with related health care costs exceeding $287 billion. As spinal fusion involves extensive instrumentation of the vertebrae, patients with skeletal abnormalities may be at increased risk for complications. However, preoperative identification of high-risk patients remains a challenge. Due to skeletal effects of aging and estrogen deficiency, postmenopausal (PM) women may be at particular risk. Dual energy x-ray absorptiometry (DXA) measurements of areal BMD are subject to artifact in patients with spinal pathology, and may be limited as screening tests. PURPOSE This prospective study investigated skeletal health in postmenopausal women having lumbar spine fusion and matched controls using DXA and high resolution peripheral QCT (HRpQCT) measurements of volumetric BMD (vBMD) and microarchitecture. We aimed to determine if HRpQCT would reveal additional abnormalities in vBMD and microarchitecture in fusion patients compared to DXA. STUDY DESIGN/SETTING Prospective, single center study. PATIENT SAMPLE A total of 60 patients were included in this study. PM women undergoing lumbar fusion were prospectively enrolled and compared to PM controls. OUTCOME MEASURES HRpQCT measurements of cortical and trabecular vBMD and microarchitecture, DXA, age and BMI. METHODS PM women undergoing lumbar fusion (n=20) were matched 1:2 by age with PM controls (n=40) who had no history of spine surgery or secondary osteoporosis. Subjects had assessments by standard DXA and high resolution peripheral QCT (HRpQCT) to measure cortical (Ct) and trabecular (Tb) vBMD and microarchitecture of the distal radius and tibia. RESULTS Mean age of subjects was 66+/-6 years, BMI (28+/-6 kg/m2) without any significant differences between groups. By DXA, T-scores in fusion patients were normal at the lumbar spine (mean 0.0) and osteopenic at the total hip (-1.2), femoral neck (-1.5) and 1/3 radius (-1.5). T- Scores did not differ significantly from controls at any site. In contrast, HRpQCT revealed low vBMD (total, Ct, Tb) in fusion patients compared to controls at both radius and tibia, with total vBMD 21-30% lower, Ct density ∼7% and Tb density ∼25% lower. Fusion patients had microarchitectural abnormalities, significantly fewer, thinner and more widely spaced trabeculae. Specifically, Tb number was 9% lower, Tb thickness 6% lower, and Tb separation 23% greater at the radius with similar differences at the tibia. CONCLUSIONS In summary, PM women presenting for spine fusion surgery had low volumetric BMD and abnormal trabecular microarchitecture, despite DXA values that were normal or slightly low. Our results suggest that additional techniques may be necessary for detection of bone quality deficits in patients presenting for spinal fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The Physical Characteristics of Elite Female Rugby Union Players

This study explored the anthropometric and body composition characteristics of elite female rugby union players, comparing between and within different playing positions. Thirty elite female rugby union players (25.6 ± 4.3 y, 171.3 ± 7.7 cm, 83.5 ± 13.9 kg) from New Zealand participated in this study. Physical characteristics were assessed using anthropometric (height, body mass, skinfolds) and body composition (dual-energy X-ray absorptiometry) measures. Forwards were significantly taller (p < 0.01; d = 1.34), heavier (p < 0.01; d = 2.19), and possessed greater skinfolds (p < 0.01; d = 1.02) than backs. Forwards also possessed significantly greater total (p < 0.01; d = 1.83–2.25) and regional (p < 0.01; d = 1.50–2.50) body composition measures compared to backs. Healthy bone mineral density values were observed in both forwards and backs, with significantly greater values observed at the arm (p < 0.01; d = 0.92) and femoral neck (p = 0.04; d = 0.77) sites for forwards. Tight-five players were significantly heavier (p = 0.02; d = 1.41) and possessed significantly greater skinfolds (p < 0.01; d = 0.97) than loose-forwards. Tight-five also possessed significantly greater total body composition measures (p < 0.05; d = 0.97–1.77) and significantly greater trunk lean mass (p = 0.04; d = 1.14), trunk fat mass (p < 0.01; d = 1.84), and arm fat mass (p = 0.02; d = 1.35) compared to loose-forwards. Specific programming and monitoring for forwards and backs, particularly within forward positional groups, appear important due to such physical characteristic differences.

Pediatric Dual-Energy X-Ray Absorptiometry in Japan: A Proposal for Shared Access to Equipment

Regular assessment of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is essential for detecting glucocorticoid-induced osteoporosis in juvenile-onset autoimmune diseases. Z-score is used to standardize osteoporosis assessment in children and is evaluated with only one of three devices in Japan. The purpose of this study was to determine how many Japanese medical facilities for pediatric rheumatic diseases were unable to use Z-scores to evaluate osteoporosis. Electronic questionnaires were distributed between 2017 and 2019 to hospitals belonging to the Pediatric Rheumatology Association of Japan and to university hospitals and public children's hospitals that provide medical care for pediatric rheumatic diseases. The questionnaire inquired about the location of DXA measurement, manufacturer (Hologic, GE healthcare, Hitachi), and measurement site, and the answers were collected using Google Forms. Statcel 4 was used for analysis. Overall, 120 facilities responded to the survey, of which 117 had DXA. In the remaining three facilities, DXA was not installed in two and was out of order in one. Bone loss in childhood was evaluated using a Z-score calculated from age-based reference values; however, 30% of hospitals without HOLOGIC DXA could not evaluate osteoporosis by Z-score in Japanese childhood. The characteristics of the hospitals enrolled in this study did not bias the selection of Hologic DXA. Neighboring institutions should consider sharing access to Hologic DXA equipment, to ensure use of uniform reference values. GE BMD reference values should be established for Japanese children.

Intermachine differences in DXA measurements vary by skeletal site, and impact the assessment of low bone density in children.

Bone mineral content (BMC) and areal-bone mineral density (aBMD) measurements of the lumbar spine (LS) and whole body less head (WBLH) by dual energy X-ray absorptiometry (DXA) are recommended for bone health assessment in children. Intermachine differences were not considered previously in formulating these recommendations. DXA measurements of the LS, WBLH, total hip, femoral neck and distal 1/3 radius from the Bone Mineral Density in Childhood Study were examined. Healthy children, ages 6 to 16years, from five clinical centers participated. The same spine, whole body, and femur phantoms were measured on each Center's DXA machine. Percentage of individuals with low BMC or aBMD (Z-score<-1.5) was determined. Clinical center differences were evaluated by analysis of covariance adjusting for height and BMI Z-score, calcium intake, physical activity, Tanner stage and bone age. Logistic regression assessed odds of low BMC or aBMD across clinical centers. Significant differences among Clinical Centers (p<0.05) were evident in adjusted mean BMC and aBMD Z-scores (n=1503) for all skeletal sites. WBLH BMC and aBMD Z-scores had the greatest range across centers (-0.13 to 0.24, and -0.17 to 0.56, respectively). The percentage of children with Z-scores less than -1.5 varied among Clinical Centers from 1.9 [95%CI 0.8, 4.5] to 8.1 [95%CI 5.7, 11.3] for WBLH BMC, 1.1 [95%CI 0.4, 3.5] to 6.3 [95%CI 3.8, 10.1] for WBLH aBMD, and from 4.4 [95%CI 2.8, 7.0] to 12.6 [95%CI 9.3, 16.9] for distal 1/3 radius aBMD. For each skeletal site except total hip aBMD and femoral neck BMC, at least one center had significantly lower odds of low bone density. By design, our reference ranges capture intermachine variability. Most clinical centers don't know where their machine falls within the range of intermachine variability, and this may affect diagnosis of children evaluated for conditions that threaten bone health. Total hip scans showed the least, and whole body scans showed the most intermachine variability. Pediatric bone health assessment recommendations should recognize intermachine differences and address this important issue.

Impaired Bone Health in Children With Biliary Atresia.

The aim of the study was to examine the frequency of rickets and bone fractures and to assess areal bone mineral density (aBMD) in childhood among patients with biliary atresia (BA). We gathered data on all patients diagnosed with BA in Finland that survived to ≥1 year of age between 1 January 2000 to 30 June 2018. Data on gestational age, birth weight, postsurgical medications, and history of rickets and bone fractures were collected retrospectively. Serum levels of 25-hydroxyvitamin D [25(OH)D] postportoenterostomy (PE) were collected. Plain radiographs and dual energy X-ray absorptiometry (DXA) measurements of study subjects were reviewed. Out of 49 patients, 7 (14%) were diagnosed with rickets during infancy. Clearance of jaundice [odds ratio 0.055, 95% confidence interval [CI] 0.00266-0.393; P < 0.01] was a protective factor against rickets. Sufficient 25(OH)D levels were reached 3 months post-PE. Eleven (22%) patients suffered at least one bone fracture (range 1-9) during childhood and adolescence. In DXA measurements, median lumbar spine aBMD anthropometrically adjusted z-scores were as follows: in native liver survivors 0.8 (interquartile range [IQR] -1.9 to 1.4) at 5 and -0.3 (IQR -1.3 to 0.8) at 10 years and for liver transplanted patients 0.4 (IQR -0.2 to 1.1) at 5 and 0.6 (IQR -0.1 to 1.3) at 10 years. BA patients have an increased risk for rickets and bone fractures compared with the normal population. Most BA patients have aBMD within normal range between 5 and 10 years of age irrespective of liver transplantation status.