Spine Dual-energy X-ray Absorptiometry Research Articles

Cognitive function and skeletal size and mineral density at age 6–7 years: Findings from the Southampton Women's Survey

IntroductionPoor cognitive function and osteoporosis commonly co-exist in later life. In women, this is often attributed to post-menopausal estrogen loss. However, a common early life origin for these conditions and the associations between cognitive function and bone mineral density (BMD) in childhood have not previously been explored. We examined these relationships at age 6–7 years in the Southampton Women's Survey (SWS) mother-offspring cohort. MethodsChild occipitofrontal circumference (OFC), a proxy for brain volume, intelligence quotient (IQ) [Wechsler Abbreviated Scale of Intelligence] and visual recognition and working memory [CANTAB® Delayed Matching to Sample (DMS) and Spatial Span Length (SSP), respectively] were assessed. Whole-body-less-head (WBLH) and lumbar spine dual-energy X-ray absorptiometry [Hologic Discovery] (DXA) were performed to measure bone area (BA), bone mineral content (BMC), BMD and bone mineral apparent density (BMAD). Linear regression was used to examine associations between age and sex standardized variables (β represent standard deviation (SD) difference per SD of cognitive function). ResultsDXA was performed in 1331 children (mean (SD) age 6.8 (0.33) years, 51.5 % male), with OFC, IQ, DMS and SSP assessed in 1250, 551, 490 and 460, respectively. OFC (β = 0.25 SD/SD, 95%CI 0.20,0.30), IQ (β = 0.11 SD/SD, 95%CI 0.02,0.19), and DMS (β = 0.11, SD/SD, 95%CI 0.01,0.20) were positively associated with WBLH BA, with similar associations for lumbar spine BA. OFC and DMS were also positively associated with WBLH BMC, but only OFC was associated with BMD (WBLH: β = 0.38 SD/SD, 95%CI 0.33,0.43; LS: β = 0.19 SD/SD, 95%CI 0.13,0.24). ConclusionChildhood brain volume was positively associated with measures of skeletal size and BMD, whereas IQ and memory were associated only with skeletal size. These findings suggest that common early life determinants for skeletal growth and BMD and cognitive function should be explored to identify potential early-life approaches to preventing osteoporosis and cognitive decline.

Longitudinal Association between L1 Trabecular Attenuation from Chest Computed Tomography (CT) and Bone Mineral Density from Dualenergy X-ray Absorptiometry (DXA).

Many studies have shown that vertebral trabecular attenuation measured on CT scan corresponds well to DXA results for bone mineral density. These studies were based on crosssectional data. Hence, there were limitations in explaining the constantly changing vertebral trabecular attenuation from CT and T-score from DXA over time. This study aimed to determine the longitudinal association between the vertebral trabecular attenuation measured on computed tomography (CT) and the T-score measured by dual-energy X-ray absorptiometry (DXA). We performed a database search for 333 patients who underwent surgery for breast cancer, preoperative treatment, and at least one follow-up chest CT and DXA from January, 2013 through May, 2021. One musculoskeletal radiologist measured the mean vertebral trabecular attenuation of lumbar vertebra 1(L1) on axial unenhanced images at the pedicle level by manually placing the region of interest (ROI). DXA of the lumbar spine was performed, and the lowest T-score of the lumbar spine was used for the analysis. We evaluated the association between L1 trabecular attenuation from chest CT and T-score from DXA over time using the generalized estimating equations (GEE) model to analyze longitudinal corrected data. A total of 150 women (mean age, 52.4 ± 11.0 years) were included. There was a statistically significant association between L1 trabecular attenuation from chest CT and T-score from DXA in the unadjusted model (p < 0.001) and adjusted model (p < 0.001). T-score value increased by 0.172 (95% confidence interval (CI): 0.145-0.200, p < 0.001) per 10 unit (HU) of L1 trabecular attenuation at time = 0 in unadjusted model and by 0.173 (95% CI: 0.143-0.203, p < 0.001) in all adjusted model. We demonstrated that L1 attenuation from chest CT images was longitudinally associated with T-score from DXA, and the degree of association appeared to be decreased over time in breast cancer patients regardless of their medical condition.

Evaluating alternatives to dual-energy x-ray absorptiometry for assessing bone quality in patients undergoing spine surgery.

The purpose of this study was to compare and contrast lumbar bone quality and osteoporosis/osteopenia screening results via dual-energy x-ray absorptiometry (DEXA), CT, and MRI. A consecutive series of 426 candidates screened for lumbar disc replacement over a 5-year period beginning in 2018 was reviewed. Patients with a preoperative lumbar spine DEXA scan and a CT and/or MRI scan were included. The primary outcome measures included the bone mineral density (BMD) and osteoporosis or osteopenia classification from DEXA scans, Hounsfield units (HUs) for CT, and vertebral bone quality (VBQ) assessment for MRI. Patients were included if they had a DEXA scan within 1 year of an MRI or CT scan. DEXA BMD scores from composite or level-by-level reports were recorded. Asynchronous MRI and CT measurements were conducted using PACS. Interrater and intrarater reliability scores were generated for both CT and MRI measurements and ranged from 1.000 for MRI L1-4 scans to 0.683 for MRI VBQ. All 3 types of scans were statistically significantly correlated with one another; however, CT was more strongly correlated with the lumbar DEXA value (r = 0.439, p < 0.001). The correlation between MRI VBQ and DEXA was -0.103, (p < 0.045). The CT level-by-level measurements correlate with the corresponding level-by-level DEXA BMD values (correlation ranging from 0.531 to 0.289, p < 0.001 to p = 0.007). CT HU values were more strongly related to osteoporosis/osteopenia classification based on DEXA T-scores than were MRI VBQ values. Receiver operating characteristic analyses found that the area under the curve was 0.817 for CT and 0.539 for MRI. These results demonstrate that CT HUs more closely correlate to DEXA scores than MRI VBQ in this population of patients undergoing surgery for symptomatic disc degeneration. Thus, CT may be an alternative to DEXA for assessing VBQ in this population.

Trabecular structural difference between the superior and inferior regions of the vertebral body: a cadaveric and clinical study.

Osteoporotic vertebral compression fractures commonly involve the superior vertebral body; however, their associated causes have not yet been clearly established. This study aimed to determine the trabecular structural differences between the superior and inferior regions of the vertebral body using cadaveric and clinical studies. First, five vertebrae were collected from three human cadavers. The trabecular structures of the superior and inferior regions of each vertebral body were analyzed using micro-computed tomography (micro-CT), finite element analysis (FEA), and biomechanical test. Based on the results of the ex vivo study, we conducted a clinical study. Second, spine CT images were retrospectively collected. Bone volume and Hounsfield unit were analyzed for 192 vertebral bodies. Finally, after sample size calculation based on the pilot study, prospectively, 200 participants underwent dual-energy X-ray absorptiometry (DXA) of the lateral spine. The bone mineral densities (BMDs) of the superior and inferior regions of each lumbar vertebral body were measured. The paired t-test and Wilcoxon signed-rank test were used for the statistical analyses, and p-value < 0.05 was considered significant. Cadaver studies revealed differences between the superior and inferior trabecular bone structures. The bone volume ratio, BMD, and various other trabecular parameters advocated for decreased strength of the superior region. Throughout the biomechanical study, the limitations of the compression force were 3.44 and 4.63 N/m2 for the superior and inferior regions, respectively. In the FEA study, the inferior region had a lower average displacement and higher von Mises stress than the superior region. In the clinical spine CT-based bone volume and BMD study, the bone volume was significantly higher in the inferior region than in the superior region. In the lateral spine DXA, the mean BMD of the superior region of vertebral bodies was significantly lower compared with that of the inferior region. The superior trabecular structure of the lumbar vertebral bodies possesses more biomechanical susceptibility compared with the inferior trabecular structure, confirming its dominant role in causing osteoporotic vertebral fractures. Physicians should also focus on the BMD values of the superior region of the vertebral body using lateral spine DXA to evaluate osteoporosis.

Trabecular Bone Score as a More Sensitive Tool to Evaluate Bone Involvement in MEN1-related Primary Hyperparathyroidism.

The skeletal involvement of multiple endocrine neoplasia type 1-related primary hyperparathyroidism (MHPT) is not exactly the same as that of sporadic primary hyperparathyroidism (SHPT). Trabecular bone score (TBS) as a texture parameter has been reported to reflect trabecular bone damage. This study aimed to compare the clinical characteristics, especially the skeletal involvement, between patients with MHPT and SHPT. The clinical characteristics were retrospectively collected in 120 patients with MHPT and compared with 360 patients with SHPT in the same period. Dual-energy X-ray absorptiometry were conducted in some patients with MHPT, in whom bone mineral density (BMD) and calculated TBS derived from lumbar spine dual-energy X-ray absorptiometry images were compared with those of patients with SHPT. Although the duration of disease in the MHPT group was longer, the age at hospital visit was significantly lower than that in the SHPT group (43.5 [interquartile range, 31.5-52.0] vs 52.0 [interquartile range, 40.5-61.0], P < .001). The proportion of skeletal involvement in the MHPT group was significantly lower. However, in the subgroup of MHPT cases (n = 86) with data of BMD, there was no significant difference in skeletal involvement from SHPT cases matched for gender and age. Although the BMD and TBS in the lumbar spines of patients with MHPT were lower than those of patients with SHPT (BMD: 0.91 ± 0.18 g/cm2 vs 1.01 ± 0.17 g/cm2; TBS: 1.22 ± 0.14 vs 1.29 ± 0.11, P < .001). According to TBS, among 34 patients with MHPT with normal BMD, 15 patients had bone microstructure damage. The cancellous bone microarchitecture was more severely damaged in patients with MHPT according to TBS, which suggested that TBS could be a sensitive supplemental index in addition to BMD to identify bone-involvement risk in patients with MHPT.

Evaluation of AI-based spine segmentation (SpS) for the analysis of lumbar spine dual energy X-ray absorptiometry scans

Evaluation of AI-based spine segmentation (SpS) for the analysis of lumbar spine dual energy X-ray absorptiometry scans

Age-related trajectory of bone density in children with intestinal failure: A longitudinal retrospective cohort study.

Longitudinal changes in bone health in children with intestinal failure (IF) are unclear. We aimed to better understand the trajectory of bone mineral status over time in children with IF and identify clinical factors that influence the trajectory. Clinical records of patients attending the Intestinal Rehabilitation Center of Cincinnati Children's Hospital Medical Center between 2012 and 2021 were reviewed. Children diagnosed with IF before age 3 years with at least two lumbar spine dual-energy x-ray absorptiometry scans were included. We abstracted information on medical history, parenteral nutrition, bone density, and growth. We calculated bone density z scores with and without adjustment for height z scores. Thirty-four children with IF met inclusion criteria. Children were shorter than average with a mean height z score of -1.5 ± 1.3. The mean bone density z score was -1.5 ± 1.3 with 25 of the cohort having a z score < -2.0. After height adjustment, the mean bone density z score was -0.42 ± 1.4 with 11% below -2.0. Most dual-energy x-ray absorptiometry scans (60%) had a feeding tube artifact. Bone density z scores increased slightly with age and lower parenteral nutrition dependency and were higher in scans without an artifact. Etiologies of IF, line infections, prematurity, and vitamin D status were not associated with height-adjusted bone density z scores. Children with IF were shorter than expected for age. Deficits in bone mineral status were less common when adjusting for short stature. Etiologies of IF, prematurity, and vitamin D deficiency were not associated with bone density.

Trabecular Bone Score Vertebral Exclusions Affect Risk Classification and Treatment Recommendations: The Manitoba Bmd Registry

Lumbar spine trabecular bone score (TBS), a texture measure derived from spine dual-energy x-ray absorptiometry (DXA) images, is a bone mineral density (BMD)-independent risk factor for fracture. Lumbar vertebral levels that show structural artifact are excluded from BMD measurement. TBS is relatively unaffected by degenerative artifact, and it is uncertain whether the same exclusions should be applied to TBS reporting. To gain insight into the clinical impact of vertebral exclusion on TBS, we examined the effect of lumbar vertebral exclusions in routine clinical practice on tertile-based TBS categorization and TBS adjusted FRAX-based treatment recommendations. The study population consisted of 71,209 individuals aged 40 years and older with narrow fan-beam spine DXA examinations and retrospectively-derived TBS. During BMD reporting, 34.3% of the scans had one or more vertebral exclusions for structural artifact. When TBS was derived from the same vertebral levels used for BMD reporting, using fixed L1-L4 tertile cutoffs (1.23 and 1.31 from the McCloskey meta-analysis) reclassified 17.9% to a lower and 6.5% to a higher TBS category, with 75.6% unchanged. Reclassification was reduced from 24.4% overall to 17.2% when level-specific tertile cutoffs from the software manufacturer were used. Treatment reclassification based upon FRAX major osteoporotic fracture probability occurred in 2.9% overall, but in 9.6% of those with baseline risk ≥15%. For treatment based upon FRAX hip fracture probability, reclassification occurred in 3.4% overall, but in 10.4% in those with baseline risk ≥2%. In summary, lumbar spine TBS measurements based upon vertebral levels other than L1-L4 can alter the tertile category and treatment recommendations based upon TBS-adjusted FRAX calculation, especially for those close to or exceeding the treatment cut-off. Manufacturer level-specific tertile cut-offs should be used if vertebral exclusions are applied.

FRAX Adjustment by Trabecular Bone Score with or Without Bone Mineral Density: The Manitoba BMD Registry

Trabecular bone score (TBS), a texture measure derived from spine dual-energy x-ray absorptiometry (DXA) images, is a FRAX®-independent risk factor for fracture. The TBS adjustment to FRAX assumes the presence of femoral neck BMD in the calculation. However, there are many individuals in whom hip DXA cannot be acquired. Whether the TBS-adjustment would apply to FRAX probabilities calculated without BMD has not been studied. The current analysis was performed to evaluate major osteoporotic fracture (MOF) and hip fracture risk adjusted for FRAX with and without femoral neck BMD. The study cohort consisted of 71,209 individuals (89.8% female, mean age 64.0 years). During mean follow-up 8.7 years, 6743 (9.5%) individuals sustained one or more incident MOF, of which 2037 (2.9%) sustained a hip fracture. Lower TBS was significantly associated with increased fracture risk when adjusted for FRAX probabilities, with a slightly larger effect when BMD was not included. Inclusion of TBS in the risk calculation gave a small but significant increase in stratification for fracture probabilities estimated with and without BMD. Calibration plots showed very minor deviations from the line of identity, indicating overall good calibration. In conclusion, the existing equations for incorporating TBS in FRAX estimates of fracture probability work similarly when femoral neck BMD is not used in the calculation. This potentially extends the range of situations where TBS can be used clinically to those individuals in whom lumbar spine TBS is available but femoral neck BMD is not available.

Associations of Lean Mass, Muscular Strength, and Physical Function with Trabecular Bone Score in Older Adults

Introduction/Background: Trabecular bone score (TBS) is an indirect measurement of bone quality and microarchitecture determined from dual-energy X-ray absorptiometry (DXA) imaging of the lumbar spine. TBS predicts fracture risk independent of bone mass/density, suggesting this assessment of bone quality adds value to the understanding of patients’ bone health. While lean mass and muscular strength have been associated with higher bone density and lower fracture risk among older adults, the literature is limited regarding the relationship of lean mass and strength with TBS. The purpose of this study was to determine associations of DXA-determined total body and trunk lean mass, maximal muscular strength, and gait speed as a measure of physical function, with TBS in 141 older adults (65-84 yr, 72.5 +/- 5.1 yr, 74% women). Methodology: Assessments included lumbar spine (L1-L4) bone density and total body and trunk lean mass by DXA, lower body (leg press) and upper body (seated row) strength by one repetition maximum tests, hand grip strength, and usual gait speed. TBS was derived from the lumbar spine DXA scan. Multivariable linear regression determined the contribution of proposed predictors to TBS. Results: After adjusting for age, sex, and lumbar spine bone density, upper body strength significantly predicted TBS (unadjusted/adjusted R2= 0.16/ 0.11, β coefficient =0.378, p=0.005), while total body lean mass index showed a trend in the expected direction (β coefficient =0.243, p=0.053). Gait speed and grip strength were not associated with TBS (p>0.05). Conclusion: Maximum strength of primarily back muscles measured as the seated row appears important to bone quality as measured by TBS, independent of bone density. Additional research on exercise training targeting back strength is needed to determine its clinical utility in preventing vertebral fractures among older adults.

Vertebral Level Variations in Trabecular Bone Score and Effect on Fracture Prediction: The Manitoba BMD Registry

Trabecular bone score (TBS), a texture measure derived from spine dual-energy x-ray absorptiometry (DXA) images, is a bone mineral density (BMD)-independent risk factor for fracture. TBS is reportedly insensitive to degenerative changes, and it is uncertain whether the same rules for excluding lumbar vertebral levels from BMD measurement should be applied to TBS. The current analysis was performed to explore inter-vertebral variation in TBS measurements from L1 to L4, how this relates to clinically identified structural artifact resulting in vertebral level exclusion from BMD reporting, and area under the curve (AUC) for incident fracture. The study population comprised 70,762 individuals aged 40 years and older at the time of baseline spine DXA assessment (mean age 64.1 years, 89.7% female), among whom 24,289 (34.3%) had one or more vertebral exclusions. Both TBS and BMD showed a similar cranial/caudal inter-vertebral gradient. Compared with L1-4, TBS from L1 alone was lower (mean difference -0.096; -7.6%) while TBS from L4 alone was 0.046 (3.6%) greater, similar in those without and with visual structural artifact. During mean follow-up of 8.7 years, 6744 (9.5%) individuals sustained incident major osteoporotic fractures. TBS from L1 alone gave significantly higher AUC for incident fracture than L1-4, which was in turn significantly higher than L2, L3 and L4 alone, seen in those without and with visual structural artifact. In contrast, AUCs for BMD showed minimal variation from L1 to L4, and was higher for L1-4 than for any individual lumbar vertebral level. In summary, we found inter-vertebral TBS variations within the lumbar spine are overall similar to BMD but are relatively unaffected by visual structural artifact. Fracture outcomes showed the strongest association with TBS measured from L1 alone. Further investigation is need to understand the cause and clinical application of these differences.

Correlation between bone density measurements on CT or MRI versus DEXA scan: A systematic review

BackgroundNovel methods of bone density assessment using computed tomography (CT) and magnetic resonance imaging (MRI) have been increasingly reported in the spine surgery literature. Correlations between these newer measurements and traditional Dual-Energy X-ray Absorptiometry (DEXA) is not well known. The purpose of this study is to perform an updated systematic review of correlations between bone mineral density (BMD) from CT or MRI and DEXA. MethodsArticles published between 2011 and 2021 that reported correlations between the CT-HU or MRI measurements to DEXA t-scores or BMD of lumbar spine or hip were included in this systematic review. ResultsA total of 25 studies (15 CT, 10 MRI) met the inclusion criteria with a total number of 2,745 patients. The pooled correlation coefficient of spine CT-HU versus spine DEXA, spine CT-HU versus hip DEXA and spine CT-HU versus lowest t-score were 0.60, 0.50 and 0.60 respectively. Regarding spine DEXA parameters, the pooled r2 for spine CT-HU versus spine t-score was 0.684 and spine CT-HU versus spine BMD was 0.598. Furthermore, in patients undergoing spine surgery in four studies, the pooled correlation between spine CT and spine DEXA was (r2: 0.64). In MRI studies, the pooled r2 of spine MRI versus spine DEXA and spine MRI versus hip DEXA were -0.41 and -0.44 respectively. ConclusionsCT-HU has stronger correlations with DEXA than MRI measurements. Lumbar CT-HU has the highest pooled correlation (r2 = 0.6) with both spine DEXA and lowest skeletal t-score followed by lumbar CT-HU with hip DEXA (r2 = 0.5) and lumbar MRI with hip (r2 = 0.44) and spine (r2 = 0.41) DEXA. Both imaging modalities achieved only a moderate correlation with DEXA. Few studies in both modalities have investigated the correlation in spine surgery populations and the available data shows that the correlations are worse in the degenerative spine population. A careful interruption of CT HU and MRI measurement when evaluation of BMD as they only moderately correlated with DEXA scores. At this time, it is unclear which modality is a better predictor of mechanical complications and clinical outcomes in spine surgery patients.

Trabecular bone score, bone marrow fat and vertebral fractures in cushing syndrome.

Prediction of fragility fractures in Cushing syndrome (CS) is a challenge since dual energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) does not capture all the alterations in bone microstructure induced by glucocorticoid excess. In this study we investigated the relationship between trabecular bone score (TBS), bone marrow fat (BMF) and vertebral fractures (VFs) in endogenous CS. Cross-sectional. Thirty subjects (7 M and 23 F, mean age 44.8 ± 13.4 yrs, range: 25-71) with active hypercortisolism were evaluated for VFs by quantitative morphometry, BMD and TBS by lumbar spine DXA and BMF by single-voxel magnetic resonance spectroscopy of vertebral body of L3. Subjects with VFs (17 cases; 56.7%) had higher BMF (P = 0.014) and lower BMD T-score (P = 0.012) and TBS (P = 0.004) as compared to those without VFs. Prevalence of VFs resulted to be significantly higher in individuals with impaired TBS as compared to those with normal TBS (77.8% vs. 25.0%; P = 0.008). Among patients with VFs, only 6 (35.3%) had either osteoporosis or "low BMD for age". In logistic regression analysis, impaired TBS maintained the significant association with VFs [odds ratio (OR) 6.60, 95% C.I. 1.07-40.61; P = 0.042] independently of BMF (OR 1.03, 95% C.I. 0.99-1.08; P = 0.152). TBS might be more accurate than BMF in identifying subjects with active CS and skeletal fragility at risk of VFs. Excess in glucocorticoids is associated with alterations in bone remodeling and metabolism, leading to fragility fractures regardless of bone mineral density, making more challenging for the clinician the identification of high-risk population and the definition of preventing strategies. In this context, instrumental parameters suggestive of bone quality alterations and predictive of increased fracture risk are needed. In this study, we found CS patients to have bone quality alterations as indicated by the decreased trabecular bone score and increased bone marrow fat, as measured by DEXA and MRI respectively. Both parameters were associated with high risk of VFs, and were inversely correlated, although TBS seems to be more accurate than BMF in fractures prediction in this clinical setting.

The Relationship between Bone Mineral Densitometry and Visceral Adiposity Index in Postmenopausal Women.

It was aimed to compare visceral adiposity index (VAI) levels in patients with normal bone mineral density (BMD), osteopenia, and osteoporosis. One hundred twenty postmenopausal women (40 with normal BMD, 40 with osteopenia, and 40 with osteoporosis) between the ages of 50 to 70 years were included in the study. For females, the VAI was calculated using the formula (waist circumference [WC]/[36.58 + (1.89 x body mass index (BMI))]) x (1.52/High-density lipoprotein [HDL]-cholesterol [mmol/L]) x (triglyceride [TG]/0.81 [mmol/L]). The time of menopause from the beginning was similar in all groups. Waist circumference was found to be higher in those with normal BMD than in the osteopenic and osteoporotic groups (p = 0.018 and p < 0.001, respectively), and it was also higher in the osteopenic group than in the osteoporotic group (p = 0.003). Height and body weight, BMI, blood pressure, insulin, glucose, HDL-cholesterol, and homeostasis model assessment-insulin resistance (HOMA-IR) levels were similar in all groups. Triglyceride levels were found to be higher in the normal BMD group, compared with the osteoporotic group (p = 0.005). The level of VAI was detected as higher in those with normal BMD, compared with the women with osteoporosis (p = 0.002). Additionally, the correlation analysis showed a positive correlation between dual-energy X-ray absorptiometry (DXA) spine T-scores, WC, VAI, and a negative correlation between DXA spine T-scores and age. In our study, we found higher VAI levels in those with normal BMD, compared with women with osteoporosis. We consider that further studies with a larger sample size will be beneficial in elucidating the entity.

Association of hepatic/pancreatic iron overload evaluated by quantitative T2* MRI with bone mineral density and trabecular bone score

BackgroundIron-overloaded patients are recognized as presenting an increased risk of osteoporosis. However, studies on the correlation between osteoporosis and organ iron overload are controversial or scarce. The aim of this study is to assess bone mineral density (BMD) and trabecular bone score (TBS) in correlation with hepatic and pancreatic iron overload.MethodsForty-one patients diagnosed with hemoglobinopathies, were studied. BMDs of the lumbar spine (LS), femoral neck (FN), and total hip (TH) were analyzed by Dual-energy X-ray absorptiometry (DXA) scan. LS bone quality was derived from each spine DXA examination using the TBS analysis. Hepatic and pancreatic iron overload were obtained with a multi-echo gradient echo T2* technique.ResultsAbnormal microarchitecture and abnormal bone mass were observed in 19/41 (46.3%) and 9/41 (22.0%) patients, respectively. For 26 males, BMD, T-score and Z-score of LS were significantly lower among subjects with moderate-severe hepatic iron-overload than their counterparts, as it is between no- and pancreatic iron-overload groups. For 15 females, patients with moderate-severe hepatic iron-overload had significantly lower BMD and T-score of FN and TH, and patients with pancreatic iron-overload had significantly lower BMD, T-score of FN, and lower BMD, T-score and Z-score of TH than their counterparts. Moreover, pancreatic T2*-value was positively correlated with BMD and T-score at all analyzed sites and Z-score at TH.ConclusionThese data showed lower bone mass in patients with organ iron overload, particularly for LS in males, FN and TH in females. TBS may well represent a complementary tool for the evaluation of bone quality and the risk of fracture in iron-overloaded patients.

Ethnicity and Fracture Risk Stratification from Trabecular Bone Score in Canadian Women: The Manitoba BMD Registry

Lumbar spine Trabecular Bone Score (TBS), a grey-level texture measure derived from spine dual-energy x-ray absorptiometry (DXA) images, is a bone mineral density (BMD)-independent risk factor for fracture. An unresolved and controversial question is whether there are ethnic differences that affect the utility of TBS for fracture risk assessment. The current analysis examined whether self-identified ethnicity (White, Asian, Black) in women age 40 years and older referred for DXA testing affected fracture risk stratification from TBS using a large clinical registry. The study population comprised 63,078 White women, 1,915 Asian women and 329 Black women (n=329) with mean follow up 9.0±5.2 years. There were between group differences in BMI (Black>White>Asian), lumbar spine fat percentage (Asian>White>Black) and lumbar spine tissue thickness (Black>White>Asian). Despite this, lumbar spine TBS was not significantly different between the subgroups, though there was a significant difference in lumbar spine and total hip BMD (Black >White>Asian). TBS provided significant stratification for MOF and any fracture for all ethnicity subgroups, and for hip fracture in White and Asian subgroups (insufficient numbers for analysis in Black women). No significant difference in White vs. Asian or White vs. Black women were identified using a Bonferroni adjusted p-value. In summary, we found that lumbar spine TBS measurements were similar among White, Asian and Black women referred for DXA assessment in Manitoba, Canada. TBS and BMD measurements significantly stratified fracture risk in all three populations without a meaningful difference between groups. This suggests that TBS does not need to be used differently in White vs. non-White populations.

Bone Mineral Density and Vascular Calcification in Children and Young Adults With CKD 4 to 5 or on Dialysis

Older adults with chronic kidney disease (CKD) can have low bone mineral density (BMD) with concurrent vascular calcification. Mineral accrual by the growing skeleton may protect young people with CKD from extraosseous calcification. Our hypothesis was that children and young adults with increasing BMD do not develop vascular calcification. This was a multicenter longitudinal study in children and young people (5-30 years) with CKD stages 4 to 5 or on dialysis. BMD was assessed by tibial peripheral quantitative computed tomography (pQCT) and lumbar spine dual-energy X-ray absorptiometry (DXA). The following cardiovascular imaging tests were undertaken: cardiac computed tomography for coronary artery calcification (CAC), ultrasound for carotid intima media thickness z-score (cIMTz), pulse wave velocity z-score (PWVz), and carotid distensibility for arterial stiffness. All measures are presented as age-adjusted and sex-adjusted z-scores. One hundred participants (median age 13.82 years) were assessed at baseline and 57 followed up after a median of 1.45 years. Trabecular BMD z-score (TrabBMDz) decreased (P= 0.01), and there was a nonsignificant decrease in cortical BMD z-score (CortBMDz) (P= 0.09). Median cIMTz and PWVz showed nonsignificant increase (P= 0.23 and P= 0.19, respectively). The annualized increase in TrabBMDz (ΔTrabBMDz) was an independent predictor of cIMTz increase (R 2= 0.48, β= 0.40, P= 0.03). Young people who demonstrated statural growth (n= 33) had lower ΔTrabBMDz and also attenuated vascular changes compared with those with static growth (n= 24). This hypothesis-generating study suggests that children and young adults with CKD or on dialysis may develop vascular calcification even as their BMD increases. A presumed buffering capacity of the growing skeleton may offer some protection against extraosseous calcification.

ODP127 Trabecular Bone Score and Advanced Glycation End Products In Adults with Type 1 Diabetes

Abstract Background Individuals with type 1 diabetes (T1D) have a two- to threefold increase in fracture risk at any site, and up to a sevenfold increase in hip fracture risk compared to those without diabetes. Reduced bone quality appears to contribute to the increased fracture risk observed in this population. Advanced glycation end products (AGEs) tissue accumulation, which reflects long-term glycemic control, may influence bone quality in T1D. Objective We aimed to determine if skin AGEs, as a surrogate marker for bone AGEs, are associated with vertebral trabecular bone score (TBS),anindex of bone microarchitecture derived from lumbar spine dual-energy X-ray absorptiometry (DXA) images and evaluating bone quality. Methods We present preliminary data from subjects with T1D who participated in a cross-sectional study aiming at comparing the prevalence of vertebral fractures between adult subjects with T1D from two tertiary care centers and age-, sex- and BMI-matched controls without diabetes. TBS and bone mineral density (BMD) were assessed using DXA. Skin AGEs were measured by skin autofluorescence. Simple and multiple linear regression analyses were used to explore the factors associated with TBS. Results One hundred and six subjects with T1D (52.8% women; mean age 42.7±14.7 years; mean BMI 26.9±5.6 kg/m 2; mean diabetes duration 27.6±12.3 years; 48.1% with a microvascular complication; mean HbA 1C in the preceding 3 years 7.5±0.9%; mean skin AGEs 2.15±0.54 units; mean TBS 1.428±0.113) were included. Higher skin AGEs were associated with a lower TBS in simple regression analysis (p=0. 012). In multiple linear regression, older age, male sex, higher BMI, current smoking, higher serum calcium, lower lumbar spine and femoral neck BMD, but not skin AGEs, were significantly associated with a lower TBS (model adjusted R 2 =0.65). Conclusion In this population with relatively well-controlled T1D, skin AGEs were not independently associated with TBS. Presentation: No date and time listed

Updated trabecular bone score accounting for the soft tissue thickness (TBSTT) demonstrated significantly improved bone microstructure with denosumab in the FREEDOM TBS post hoc analysis

SummaryTBS algorithm has been updated to account for regional soft tissue noise. In postmenopausal women with osteoporosis, denosumab improved tissue thickness–adjusted TBS vs placebo independently of bone mineral density over 3 years, with the magnitude of changes from baseline or placebo numerically greater than body mass index–adjusted TBS.IntroductionTo evaluate the effect of denosumab on bone microarchitecture assessed by trabecular bone score (TBS) in the FREEDOM study using the updated algorithm that accounts for regional soft tissue thickness (TBSTT) in dual-energy X-ray absorptiometry (DXA) images and to compare percent changes from baseline and placebo with classical body mass index (BMI)–adjusted TBS (TBSBMI).MethodsPostmenopausal women with lumbar spine or total hip bone mineral density (BMD) T score < − 2.5 and ≥ − 4.0 received placebo or denosumab 60 mg subcutaneously every 6 months. TBSBMI and TBSTT were assessed on lumbar spine DXA scans at baseline and months 1, 12, 24, and 36 in a subset of 279 women (129 placebo, 150 denosumab) who completed the 3-year FREEDOM DXA substudy and rolled over to open-label extension study.ResultsBaseline characteristics were similar between groups. TBSTT in the denosumab group showed numerically greater changes from both baseline and placebo than TBSBMI at months 12, 24, and 36. Denosumab led to progressive increases in BMD (1.2, 5.6, 8.1, and 10.5%) and TBSTT (0.4, 2.3, 2.6, and 3.3%) from baseline to months 1, 12, 24, and 36, respectively. Both TBS changes were significant vs baseline and placebo from months 12 to 36 (p < 0.0001). As expected, BMD and TBSTT were poorly correlated both at baseline and for changes during treatment.ConclusionIn postmenopausal women with osteoporosis, denosumab significantly improved bone microstructure assessed by TBSTT over 3 years. TBSTT seemed more responsive to denosumab treatment than TBSBMI and was independent of BMD.

Cross-Sectional Study of Knee Bone Mineral Density and Fragility Fractures in Patients with Neurological Injuries and Neuromuscular Disorders

Background: Patients with neurological injury and neuromuscular disorders are at increased risk for osteoporosis and fragility fracture. This cross-sectional study investigated whether knee bone mineral density (BMD) correlates with fragility fracture in patients with neurological injury and neuromuscular injuries. Methodology: In this retrospective chart review, 435 participants underwent dual-energy X–ray absorptiometry (DXA) for BMD analysis. Distal femur and proximal tibial BMD measurements were performed as per the Toronto protocol. Spine, hip, and forearm DXA was performed following the standards of the International Society of Clinical Densitometry, 2019. Blinded and independent clinical evaluations and laboratory exams were performed. Participants were divided into groups with and without fracture confirmed by clinical history and radiography. Results: Distal femur and proximal tibial BMD were measured in 288/435 (66.2%) participants. Osteoporosis was noted in 138/288 (47.9%) patients. Fractures occurred in 95/435 participants (21.8%), including one fracture in 64/435 participants (14.7%), two fractures in 24/435 participants (5.5%), and greater than two fractures in 7/435 patients (1.6%). Fractures were noted in 23/54 (42.6%) participants with post-polio syndrome, 21/66 with brain injury (31.8%), 3/10 (30%) with brain injury and spinal cord injury, 24/98 (24.5%) with neuromuscular disorders, 9/52 (17.3%) with nontraumatic spinal cord injury, and 15/155 (9.7%) with traumatic spinal cord injury. The median BMD of the knee and hip was lower in participants with fractures. Distal femur and proximal tibial BMD (odds ratio [OR] = 0.02, 95% confidence interval [CI]: 0.01–0.45) remained independently associated with fragility fracture in multivariable analysis. Conclusion: Proximal tibial and distal femur BMD measurements offered additional information on neurological injury and neuromuscular disorders.