Age and sex are excellent predictors of bone complications in patients with type 2 diabetes with no history of osteoporotic fracture or treatment for osteoporosis.

OBJECTIVE: To identify patients with type 2 diabetes mellitus (T2DM) with no history of fracture or osteoporosis treatment who are at risk of bone complications through the assessment of bone quality and quantity. METHODS: Of the outpatients attending our clinic during 2021 to 2022, we retrospectively enrolled 137 (men/women: 85/52, median age: 65 years) consecutive patients aged ≥40 years who had T2DM but no history of fracture or osteoporosis treatment. The lumbar spine and femoral neck bone mineral density and the trabecular bone score were determined using dual-energy X-ray absorptiometry. Independent factors associated with bone disease were identified using logistic regression analysis, and odds ratios (ORs) were calculated. RESULTS: Age and female sex were significantly associated with high ORs for development of bone disease. The integrated risk of bone complications was nearly 40-fold higher in older (≥65 years) women than in younger (<65 years) men. This difference remained after adjustment for the duration of T2DM, body mass index, and HbA1c level. CONCLUSIONS: Older women have the highest risk of osteopenia and osteoporosis among patients with T2DM who have no history of fracture or osteoporosis treatment. These patients should undergo intensive monitoring for bone fragility from an early stage of their disease.

Impact of Nutrient Intake on Body Composition in Very Low-Birth Weight Infants Following Early Progressive Enteral Feeding.

Preterm infants have increased body adiposity at term-equivalent age and risk of adverse metabolic outcomes. The aim of the study was to define how nutrient intake may impact body composition (BC) of very low-birth weight infants fed with early progressive enteral feeding and standard fortification. Eighty-six infants with <1500 g birth weight were included in the BC study and stratified into extremely preterm (EP) and very preterm (VP) groups. Nutrient intake was calculated during the first 28 days and BC assessed by dual X-ray absorptiometry at discharge and by skinfold thickness at 12 months of corrected age (CA). Total nutrient intake did not differ between the groups. EP infants had a higher fat mass percentage at discharge than VP infants (24.8% vs. 19.4%, p < 0.001); lean mass did not differ. None of the nutrients had any impact on BC of EP infants. Protein intake did not result in a higher lean mass in either group; fat intake was a significant predictor of increased fat mass percentage in VP infants at discharge (p = 0.007) and body adiposity at 12 months of CA (p = 0.021). Nutritional needs may depend on gestational age and routine fortification should be used with caution in more mature infants.

Hemoglobin concentration and blood shift during dry static apnea in elite breath hold divers.

Introduction: Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD (n = 11) and matched controls (n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD. Methods and results: After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15O-H2O-PET/CT (n = 6) and cardiac MRI (n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO2max matched controls (n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations. Conclusion: Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans.

Prevalence and outcome of sarcopenia in non-alcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) includes a spectrum of conditions, progressing from mild steatosis to advanced fibrosis. Sarcopenia, characterized by decreased muscle strength and mass, shares common pathophysiological traits with NAFLD. An association exists between sarcopenia and increased NAFLD prevalence. However, data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent. AIM: To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD. METHODS: We conducted a comprehensive search for relevant studies in MEDLINE, Embase, and Scopus from their inception to June 2023. We included studies that focused on patients with NAFLD, reported the prevalence of sarcopenia as the primary outcome, and examined secondary outcomes, such as liver fibrosis and other adverse events. We also used the Newcastle-Ottawa scale for quality assessment. RESULTS: Of the 29 studies included, the prevalence of sarcopenia in NAFLD varied widely (1.6% to 63.0%), with 20 studies reporting a prevalence of more than 10.0%. Substantial heterogeneity was noted in the measurement modalities for sarcopenia. Sarcopenia was associated with a higher risk of advanced fibrosis (odd ratio: 1.97, 95% confidence interval: 1.44-2.70). Increased odds were consistently observed in fibrosis assessment through biopsy, NAFLD fibrosis score/body mass index, aspartate aminotransferase to alanine aminotransferase ratio, diabetes (BARD) score, and transient elastography, whereas the fibrosis-4 score showed no such association. Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis, insulin resistance, cardiovascular risks, and mortality. CONCLUSION: This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients. The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings. This review demonstrates the multidimensional impact of sarcopenia on NAFLD, indicating its importance beyond liver-related events to include cardiovascular risks, mortality, and metabolic complications.

Cómo estimar la composición corporal en la enfermedad de Huntington. Estudio transversal y observacional con bioimpedancia de múltiples frecuencias / How to estimate body composition in Huntington’s disease. A cross-sectional, observational study using multiple frequencies bioimpedance

Introducción La enfermedad de Huntington (EH) es un trastorno raro neurodegenerativo. La información fiable del estado nutricional, especialmente de la composición corporal, es crítica en clínica y en investigación. La facilidad de aplicación y portabilidad del análisis de la bioimpedancia de múltiples frecuencias (mfBIA) la convierten en una herramienta atractiva para medirla, pero se desconoce su precisión en la EH. Objetivo Evaluar la precisión del mfBIA frente a la absorciometría dual de rayos X (DEXA) en la EH. Pacientes y métodos Estudio transversal, observacional y unicéntrico. La EH se midió con la subescala motora de la escala unificada de valoración de la EH y con la capacidad funcional total. La composición corporal se valoró según la masa libre de grasa (MLG), la masa grasa (MG), el índice de masa libre de grasa (IMLG) y el índice de masa grasa (IMG). Se utilizó el coeficiente de correlación intraclase con intervalos de confianza al 95% y estimaciones de sesgo mediante gráficos de Bland-Altman. Resultados Se incluyó a 16 pacientes, siete hombres y nueve mujeres, con edad media de 58,5 (32-68) años, capacidad funcional total de 10 (3-13) y escala unificada de valoración de la EH de 31 (7-85). La fiabilidad era alta entre el mfBIA y la DEXA para el IMLG en hombres, 0,88 (intervalo de confianza al 95%: 0,17-0,98), y mujeres, 0,9 (intervalo de confianza al 95%: 0,61-0,98); y para el IMG en hombres, 0,97 (intervalo de confianza al 95%: 0,83-0,99), y mujeres, 0,91 (intervalo de confianza al 95%: 0,68-0,98). El mfBIA sobreestimó ligeramente la MLG, la MG, el IMG y el IMLG en los hombres, pero subestimó el IMLG en las mujeres. Conclusiones El mfBIA es un método fácil de usar, seguro, no invasivo y preciso para medir la composición corporal y el estado nutricional en pacientes con EH leve-moderada. (AU)

INTRODUCTION Huntington´s disease (HD) is a rare neurodegenerative disorder. Reliable information about nutritional status, especially body composition from individuals with HD is critical for clinical care and research. The ease of application and portability of multiple frequencies bioelectrical impedance analysis (mfBIA) make it an attractive tool for measuring body composition, but its accuracy in HD is unknown. AIM To evaluate the accuracy of mfBIA vs. Dual X-ray absorptiometry (DEXA) in HD. PATIENTS AND METHODS Cross-sectional, observational, and single-center study. HD severity was measured using motor subscale of the unified Huntington´s disease rating scale (m-UHDRS) and the total functional capacity (TFC). Body composition was measured in terms of fat-free mass (FFM), fat mass (FM), fat-free mass index (FFMI), and fat mass index (FMI). Using Bland-Altman plots, we analyzed reliability between DEXA and mfBIA using the Intraclass Correlation Coefficient with 95% confidence intervals (CI) and bias estimates for all. RESULTS We included 16 patients with HD, 7 men, and 9 women, median age of 58.5 (32;68) years, TFC: 10 (3;13), and m-UHDRS: 31 (7;85). The reliability between mfBIA and DEXA were high for FFMI in men: 0.88 (95% CI 0.17-0.98), and women: 0.90 (95% CI 0.61- 0.98); for FMI, men: 0.97 (95% CI 0.83-0.99), and women: 0.91 (95% CI 0.68-0.98). Compared to DEXA, mfBIA slightly overestimated FFM, FM, FMI and FFMI in men and underestimated FFMI in women. CONCLUSIONS mfBIA is an easy-to-use, safe, non-invasive, accurate method for measuring body composition and nutritional status in patients with mild-moderate HD. (AU)

Osteoporosis and bone health in pediatric patients with epidermolysis bullosa: A scoping review.

Nutritional compromise, low levels of vitamin D, chronic inflammation, abnormal growth, and physical inactivity affect bone metabolism and compromise long-term bone health in individuals with epidermolysis bullosa (EB). The result is a high risk for osteopenia, osteoporosis, and pathologic fractures, but this important consequence of EB has been the focus of few investigations. Our scoping review found 21 publications that assessed the current understanding and clinical practices for monitoring of osteoporosis and its treatment in EB. Recommendations summarized from 13 of these publications include early nutritional and weight assessments before 2 years of age; bloodwork every 6-12 months starting at birth; Tanner stage assessments every 6 months to detect any pubertal delay; DEXA scans starting at age 6 years with repeated scans every 1-2 years, except in mild cases; and vitamin D supplementation of 80-320 IU daily for children 0-7 years and 720 IU for patients >8 years.

The effects of high velocity resistance training on bone mineral density in older adults: A systematic review.

OBJECTIVE: To determine the effects of high velocity resistance training (HVRT) on bone mineral density (BMD) in older adults. METHODS: A systematic review was conducted using five databases. Records were screened by two independent reviewers. INCLUSION CRITERIA: adults ≥50 years old, HVRT defined as rapid concentric and slow eccentric phase against an external load, control group and/or other intervention group, BMD measured using dual X-ray absorptiometry, and ≥6 months. RESULTS: 25 studies met the inclusion criteria. 12 were original intervention studies (8 RCTs) with n = 1203 people. 13 papers were follow up studies of these original interventions. Heterogeneity of studies meant no meta-analysis was performed. Moderate evidence suggests a small statistically significant effect of HVRT on BMD in older adults at the lumbar spine, total hip, and femoral neck ranging from 0.9 % to 5.4 %. BMD measurements significantly decreased post-intervention in follow-up studies where the interventions had ceased. Dose-response of HVRT was shown to positively impact BMD when ≥2 sessions per week are completed. CONCLUSIONS: HVRT plays a role in increasing BMD of the lumbar spine, femoral neck, and total hip. Doses of higher intensity exercise performed ≥2 sessions per week will yield the most skeletal benefits, and if exercise is stopped for >6 months, benefits achieved may be lost.

Pathogenesis, assessment, and management of bone loss in axial spondyloarthritis.

INTRODUCTION: Axial spondyloarthritis (axSpA) presents a complex scenario where both new bone formation in entheseal tissues and significant trabecular bone loss coexist, emphasizing the intricate nature of bone dynamics in this context. METHODS: A search of the literature was conducted to compose a narrative review exploring the pathogenesis, possible assessment methods, and potential management options for axSpA. RESULTS: While chronic systemic and local inflammation contribute to bone loss, the mechanisms behind axSpA-associated bone loss exhibit distinct characteristics influenced by factors like mechanical stress and the gut microbiome. These factors directly or indirectly stimulate osteoclast differentiation and activation through the RANK-RANKL axis, while simultaneously impeding osteoblast differentiation via negative regulation of bone anabolic pathways, including the Wnt signaling pathway. This disruption in the balance between bone-resorbing osteoclasts and bone-forming osteoblasts contributes to overall bone loss in axSpA. Early evaluation at diagnosis is prudent for detecting bone changes. While traditional dual x-ray absorptiometry (DXA) has limitations due to potential overestimation from spinal new bone formation, alternative methods like trabecular bone score (TBS), quantitative CT (QCT), and quantitative ultrasound (QUS) show promise. However, their integration into routine clinical practice remains limited. In addition to approved anti-inflammatory drugs, lifestyle adjustments like regular exercise play a key role in preserving bone health. Tailoring interventions based on individual risk profiles holds potential for mitigating bone loss progression. CONCLUSION: Recognizing the pivotal role of bone loss in axSpA underscores the importance of integrating regular assessments and effective management strategies into clinical practice. Given the multifaceted contributors to bone loss in axSpA, a multidisciplinary approach is essential.

Quantitative CT Evaluation of Bone Mineral Density in the Thoracic Spine on 18F-Fluorocholine PET/CT Imaging in Patients With Primary Hyperparathyroidism.

INTRODUCTION: Measurement of bone mineral density (BMD) with quantitative CT (QCT) carries several advantages over other densitometric techniques, including superior assessment of the spine. As most QCT studies evaluated the lumbar spine, measurements of the thoracic spine are limited. We performed QCT analysis of the thoracic spine in a cohort of patients with primary hyperparathyroidism. MATERIALS AND METHODS: This study was a retrospective QCT analysis of the thoracic spine on 18F-fluorocholine PET/CT scans in patients with primary hyperparathyroidism patients between March 2018 and December 2022. Correlations between QCT-derived BMD or Hounsfield units (HU) and demographic data, laboratory parameters, results from histopathological examination after parathyroidectomy and results of DXA imaging were analyzed, when available. RESULTS: In 189 patients, mean QCT-derived BMD at the thoracic spine was 85.6 mg/cm3. Results from recent DXA were available in 122 patients. Mean thoracic QCT-derived BMD and HU were significantly correlated with DXA-derived BMD in lumbar spine, total hip and femoral neck and with the lowest T-score at DXA imaging. Only weak correlations were found with BMI or 18F-fluorocholine uptake, while no significant correlations were found with adenoma weight, PTH or calcium levels. CONCLUSION: Our study confirms correlation between QCT-derived BMD in the thoracic spine with age and DXA-derived BMD measurements within a population of patients with primary hyperparathyroidism. Establishment of reference BMD values for individual thoracic vertebrae, may allow direct osteoporosis classification on thoracic CT imaging.

Cross-Calibration Study of The Stratos And Hologic QDR 4500A Dual-Energy X-Ray Absorptiometers to Assess Bone Mineral Density And Body Composition.

The objective of the study was to assess the agreement between the Stratos (DMS) and QDR 4500A (Hologic) DXAs in determining whole body and regional aBMD, as well as whole body composition. Fifty-five individuals (46 women: 84%) with a mean age of 41 ± 13.0 years (range: 20 to 64) and a mean BMI of 31.9 ± 10 kg/m² (range: 12.2 to 49.5) were consecutively scanned on the same day using the two devices. Predictive equations for areal bone mineral density (aBMD) and whole body composition (WBC) were derived from linear regression of the data. The two DXAs were highly correlated (p<0.001 for all parameters) with a correlation coefficient (r) ranging from 0.89 to 0.99 for aBMD (r=0.89 for whole body, r=0.92 for radius, r=0.95 for femoral neck, r=0.96 for total hip, and r=0.99 for L1-L4). For WBC, the r value was 0.98 for lean tissue mass (LTM) and 1.0 for fat mass (FM). Paired t-tests indicated a statistically significant bias between the two DXAs for the majority of measurements, requiring the determination of specific cross-calibration equations. Compared to QDR 4500A, Stratos underestimated whole body aBMD and LTM and overestimated neck and hip aBMD and whole body FM. Conversely, no significant bias was demonstrated for mean aBMD at L1-L4 and radius. For whole body aBMD and FM, the concordance between the two DXAs was influenced by BMI. Despite a high concordance between the two DXAs, the systematic bias for aBMD and WBC measurements illustrates the need to define cross-calibration equations to compare data across systems.

Validation of Biomechanical Computed Tomography for Fracture Risk Classification in Metastatic Hormone-sensitive Prostate Cancer.

BACKGROUND: Guidelines recommend dual-energy x-ray absorptiometry (DXA) screening to assess fracture risk and benefit from antiresorptive therapy in men with metastatic hormone-sensitive prostate cancer (mHSPC) on androgen deprivation therapy (ADT). However, <30% of eligible patients undergo DXA screening. Biomechanical computed tomography (BCT) is a radiomic technique that measures bone mineral density (BMD) and bone strength from computed tomography (CT) scans. OBJECTIVE: To evaluate the (1) correlations between BCT- and DXA-assessed BMD, and (2) associations between BCT-assessed metrics and subsequent fracture. DESIGN, SETTING, AND PARTICIPANTS: A multicenter retrospective cohort study was conducted among patients with mHSPC between 2013 and 2020 who received CT abdomen/pelvis or positron emission tomography/CT within 48 wk before ADT initiation and during follow-up (48-96 wk after ADT initiation). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used univariate logistic regression to assess the associations between BCT measurements and the primary outcomes of subsequent pathologic and nonpathologic fractures. RESULTS AND LIMITATIONS: Among 91 eligible patients, the median ([interquartile range) age was 67 yr (62-75), 44 (48.4%) were White, and 41 (45.1%) were Black. During the median follow-up of 82 wk, 17 men (18.6%) developed a pathologic and 15 (16.5%) a nonpathologic fracture. BCT- and DXA-assessed femoral-neck BMD T scores were strongly correlated (R2 = 0.93). On baseline CT, lower BCT-assessed BMD (odds ratio [OR] 1.80, 95% confidence interval or CI [1.10, 3.25], p = 0.03) was associated with an increased risk of a pathologic fracture. Lower femoral strength (OR 1.63, 95% CI [0.99, 2.71], p = 0.06) was marginally associated with an increased risk of a pathologic fracture. Neither BMD (OR 1.52, 95% CI [0.95, 2.63], p = 0.11) nor strength (OR 1.14, 95% CI [0.75, 1.80], p = 0.57) was associated with a nonpathologic fracture. BCT identified nine (9.9%) men eligible for antiresorptive therapy, of whom four (44%) were not treated. Limitations include low fracture numbers resulting in lower power to detect fracture associations. CONCLUSIONS: Among men diagnosed with mHSPC, BCT assessments were strongly correlated with DXA, predicted subsequent pathologic fracture, and identified additional men indicated for antiresorptive therapy. PATIENT SUMMARY: We assess whether biomechanical computer tomography (BCT) from routine computer tomography (CT) scans can identify fracture risk among patients recently diagnosed with metastatic prostate cancer. We find that BCT and dual-energy x-ray absorptiometry-derived bone mineral density are strongly correlated and that BCT accurately identifies the risk for future fracture. BCT may enable broader fracture risk assessment and facilitate timely interventions to reduce fracture risk in metastatic prostate cancer patients.

A hierarchical clustering approach for examining the relationship between pelvis-proximal femur geometry and bone stress injury in runners.

Bone stress injury (BSI) risk in runners is multifactorial and not well understood. Unsupervised machine learning approaches can potentially elucidate risk factors for BSI by identifying groups of similar runners within a population which differ in BSI incidence. Here, a hierarchical clustering approach is used to identify groups of collegiate cross country runners based on 2-dimensional frontal plane pelvis and proximal femur geometry, which was extracted from dual-energy X-ray absorptiometry scans and dimensionally reduced by principal component analysis. Seven distinct groups were identified using the cluster tree, with the initial split being highly related to female-male differences. Visual inspection revealed clear differences between groups in pelvis and proximal femur geometry, and groups were found to differ in lower body BSI incidence during the subsequent academic year (Rand index = 0.53; adjusted Rand index = 0.07). Linear models showed between-cluster differences in visually identified geometric measures. Geometric measures were aggregated into a pelvis shape factor based on trends with BSI incidence, and the resulting shape factor was significantly different between clusters (p < 0.001). Lower shape factor values, corresponding with lower pelvis height and ischial span, and greater iliac span and trochanteric span, appeared to be related to increased BSI incidence. This trend was dominated by the effect observed across clusters of male runners, indicating that geometric effects may be more relevant to BSI risk in males, or that other factors masked the relationship in females. More broadly, this work outlines a methodological approach for distilling complex geometric differences into simple metrics that relate to injury risk.

Cross-sectional assessment of body composition and detection of malnutrition risk in participants with low body mass index and eating disorders using 3D optical surface scans.

BACKGROUND: New recommendations for the assessment of malnutrition and sarcopenia include body composition, specifically reduced muscle mass. Three-dimensional optical imaging (3DO) is a validated, accessible, and affordable alternative to dual X-ray absorptiometry (DXA). OBJECTIVE: Identify strengths and weaknesses of 3DO for identification of malnutrition in participants with low body mass index (BMI) and eating disorders. DESIGN: Participants were enrolled in the cross-sectional Shape Up! Adults and Kids studies of body shape, metabolic risk, and functional assessment and had BMI of <20 kg/m2 in adults or <85% of median BMI (mBMI) in children and adolescents. A subset was referred for eating disorders evaluation. Anthropometrics, scans, strength testing, and questionnaires were completed in clinical research centers. Lin's Concordance Correlation Coefficient (CCC) assessed agreement between 3DO and DXA; multivariate linear regression analysis examined associations between weight history and body composition. RESULTS: Among 95 participants, mean ± SD BMI was 18.3 ± 1.4 kg/m2 in adult women (N = 56), 19.0 ± 0.6 in men (N = 14), and 84.2% ± 4.1% mBMI in children (N = 25). Concordance was excellent for fat-free mass (FFM, CCC = 0.97) and strong for appendicular lean mass (ALM, CCC = 0.86) and fat mass (FM, CCC = 0.87). By DXA, 80% of adults met the low FFM index criterion for malnutrition, and 44% met low ALM for sarcopenia; 52% of children and adolescents were <-2 z-score for FM. 3DO identified 95% of these cases. In the subset, greater weight loss predicted lower FFM, FM, and ALM by both methods; a greater percentage of weight regained predicted a higher percentage of body fat. CONCLUSIONS: 3DO can accurately estimate body composition in participants with low BMI and identify criteria for malnutrition and sarcopenia. In a subset, 3DO detected changes in body composition expected with weight loss and regain secondary to eating disorders. These findings support the utility of 3DO for body composition assessment in patients with low BMI, including those with eating disorders. This trial was registered at clinicaltrials.gov as NCT03637855.

Comparison of Bone Quality Among Winter Endurance Athletes with and Without Risk Factors for Relative Energy Deficiency in Sport (REDs): A Cross-Sectional Study.

Relative Energy Deficiency in Sport (REDs) is a syndrome describing the relationship between prolonged and/or severe low energy availability and negative health and performance outcomes. The high energy expenditures incurred during training and competition put endurance athletes at risk of REDs. The objective of this study was to investigate differences in bone quality in winter endurance athletes classified as either low-risk versus at-risk for REDs. Forty-four participants were recruited (M = 18; F = 26). Bone quality was assessed at the distal radius and tibia using high resolution peripheral quantitative computed tomography (HR-pQCT), and at the hip and spine using dual X-ray absorptiometry (DXA). Finite element analysis was used to estimate bone strength. Participants were grouped using modified criteria from the REDs Clinical Assessment Tool Version 1. Fourteen participants (M = 3; F = 11), were classified as at-risk of REDs (≥ 3 risk factors). Measured with HR-pQCT, cortical bone area (radius) and bone strength (radius and tibia) were 6.8%, 13.1% and 10.3% lower (p = 0.025, p = 0.033, p = 0.027) respectively, in at-risk compared with low-risk participants. Using DXA, femoral neck areal bone density was 9.4% lower in at-risk compared with low-risk participants (p = 0.005). At-risk male participants had 21.9% lower femoral neck areal bone density (via DXA) than low-risk males (p = 0.020) with no significant differences in females. Overall, 33.3% of athletes were at-risk for REDs and had lower bone quality than those at low-risk.

Distal Tibial Bone Properties and Bone Stress Injury Risk in Young Men Undergoing Arduous Physical Training.

Trabecular microarchitecture contributes to bone strength, but its role in bone stress injury (BSI) risk in young healthy adults is unclear. Tibial volumetric BMD (vBMD), geometry, and microarchitecture, whole-body areal BMD, lean and fat mass, biochemical markers of bone metabolism, aerobic fitness, and muscle strength and power were measured in 201 British Army male infantry recruits (age 20.7 [4.3] years, BMI 24.0 ± 2.7 kg·m2) in week one of basic training. Tibial scans were performed at the ultra-distal site, 22.5 mm from the distal endplate of the non-dominant leg using High Resolution Peripheral Quantitative Computed Tomography (XtremeCT, Scanco Medical AG, Switzerland). Binary logistic regression analysis was performed to identify associations with lower body BSI confirmed by MRI. 20 recruits (10.0%) were diagnosed with a lower body BSI. Pre-injured participants had lower cortical area, stiffness and estimated failure load (p = 0.029, 0.012 and 0.011 respectively) but tibial vBMD, geometry, and microarchitecture were not associated with BSI incidence when controlling for age, total body mass, lean body mass, height, total 25(OH)D, 2.4-km run time, peak power output and maximum dynamic lift strength. Infantry Regiment (OR 9.3 [95%CI, 2.6, 33.4]) Parachute versus Line Infantry, (p ≤ 0.001) and 2.4-km best effort run time (1.06 [95%CI, 1.02, 1.10], p < 0.033) were significant predictors. Intrinsic risk factors, including ultradistal tibial density, geometry, and microarchitecture, were not associated with lower body BSI during arduous infantry training. The ninefold increased risk of BSI in the Parachute Regiment compared with Line Infantry suggests that injury propensity is primarily a function of training load and risk factors are population-specific.

Estimating fat-free mass in recreationally resistance-trained young men: Longitudinal and cross-sectional validation of different methods.

Several techniques exist to measure fat-free mass (FFM). Accordingly, this study is based on data from our recent trial comparing the sensitivity of the main field methods available with that of dual-energy X-ray absorptiometry (DXA) as reference and analyzing the cross-sectional accuracy of these field methods in recreationally resistance-trained males. We hypothesized that the use of these techniques would lead to varying estimates of FFM compared with DXA. Participants (N = 23; 21.4 ± 3.3 years) completed a 10-week resistance training plus diet intervention designed to optimize hypertrophy. FFM was determined by bioelectrical impedance analysis (BIA), 23 anthropometric equations, and DXA. After the intervention, FFM increased significantly according to BIA and most anthropometric estimates, but this increase was not detected by 2 anthropometric equations or by DXA. Only 1 of these 2 equations showed significant correlation with DXA and no standardized or significant differences to this reference method, although it did display significant heteroscedasticity. In our cross-sectional analysis, only 1 anthropometric equation gave rise to good accuracy as confirmed by DXA. Our findings indicate that the use of different techniques to assess FFM gains in response to a hypertrophic intervention yields different results. BIA with general embedded equations should not be used to monitor a young male adult's body composition. To monitor FFM over time, we would recommend the Dunne et al. equation (2) as the most sensitive field method, and to assess FFM cross-sectionally, equation (1) of these authors is the most accurate field method.

Comparison of the Discovery A and Stratos DR densitometers for assessing whole-body and regional bone mineral density and body composition.

PURPOSE: The agreement between the Stratos DR and Discovery A densitometers was assessed for measurements of whole-body (WB) and regional fat mass (FM), fat-free soft tissue (FFST) and bone mineral density (BMD). Moreover, the precision of the Stratos DR was also evaluated. METHODS: Fifty participants (35 women, 70%) were measured consecutively, once on the Discovery A and once on the Stratos DR. In a subgroup of participants (n = 29), two successive measurements with the Stratos DR were also performed. RESULTS: FM, FFST and BMD measured with the two devices were highly correlated, with a coefficient of correlation ranging from 0.80 to 0.99. Bland-Altman analyses indicated significant bias between the two devices for all measurements. Thus, compared to the Discovery A, the Stratos DR underestimated WB BMD and WB and regional FM and FFST, with the exception of trunk FM and visceral adipose tissue (VAT), which were overestimated. Precision error for the Stratos DR, when expressed as root mean square-coefficient of variation (RMS-CV%) for FM, was 1.4% for WB, 3.0% for the gynoid and android regions, and 15.9% for VAT. The RMS-CV% for FFST was 1.0% for WB. The root mean square of standard deviation for WB BMD was 0.018 g/cm², corresponding to a 1.4% CV. The least significant change was 0.050 g/cm² (SD), and 4.0% was considered to be a significant biological change. CONCLUSIONS: Differences between the Stratos DR and Discovery A measurements are significant and require the use of translational cross-calibration equations. For most of the BMD and body composition parameters, our results demonstrated good Stratos DR precision.

Quantitative CT screening improved lumbar BMD evaluation in older patients compared to dual-energy X-ray absorptiometry.

BACKGROUND: Robust evidence on whether diagnostic discordance exists between lumbar osteoporosis detected by quantitative computed tomography (QCT) vs. dual-energy X-ray absorptiometry (DXA) is still lacking. In this study involving a relatively large prospective cohort of older men (aged > 60 years) and postmenopausal women, we assessed lumbar QCT-derived volumetric bone mineral density (vBMD) and DXA-derived area BMD and evaluated their predictive performance for prevalent vertebral fracture (VF). METHODS: A total of 501 patients who underwent spinal surgery from September 2020 to September 2022 were enrolled. The criteria recommended by the American College of Radiology and the World Health Organization were used for lumbar osteoporosis diagnosis. The osteoporosis detection rates between QCT and DXA were compared. QCT-vBMD was plotted against the DXA T score, and the line of best fit was calculated based on linear regression. Multivariate logistic regression was used to analyze the associations between risk factors and VF. Receiver operating characteristic curve analysis was performed, and the corresponding area under the curve (AUC) was calculated. RESULTS: QCT screening showed that 60.7% of patients had osteoporosis, whereas DXA screening showed that 50.7% of patients had osteoporosis. Diagnoses were concordant for 325 (64.9%) patients. In all, 205 patients suffered a VF of at least one anatomic level. Of these, 84.4% (173/205) were diagnosed with osteoporosis by QCT, while only 73.2% (150/205) were diagnosed by DXA. Multivariate logistic regression showed that osteoporosis detected by QCT exhibited a stronger relationship with VF than that detected by DXA (unadjusted OR, 6.81 vs. 5.04; adjusted OR, 3.44 vs. 2.66). For discrimination between patients with and without VF, QCT-vBMD (AUC = 0.802) showed better performance than DXA T score (AUC = 0.76). CONCLUSION: In older patients undergoing spinal surgery, QCT-vBMD is more helpful than DXA in terms of osteoporosis detection rate and prediction of patients with prevalent VFs.

Muscle-to-Bone and Soft Tissue-to-Bone Ratio in Children and Adolescents with Obesity.

OBJECTIVES: To explore the total and regional muscle-to-bone ratio in children and adolescents with obesity and compare the muscle-to-bone ratio (MBR) and soft tissue-to-bone ratio (SBR) to their peers with normal weight or overweight. STUDY DESIGN: A total of 219 male and female pediatrics (mean age=12.3±2.5 years) participated in this study. Body composition was assessed with a total body dual X-ray absorptiometry. The MBR was calculated by dividing lean mass by bone mineral content. The SBR was determined by dividing the soft tissue mass (i.e., lean mass+fat mass) by bone mineral content. Differences in total and regional body composition measures between body mass index (BMI) percentile groups was assessed by ANOVA. RESULTS: The obesity group had significantly higher MBR compared to the normal weight group for total (19.24±1.56 vs. 18.26±1.64), arm (17.11±1.67 vs. 15.88±1.81), and leg (18.41±1.68 vs. 16.62±1.55). Similarly, the obesity group had significantly higher MBR in the leg (18.41±1.68) compared to the overweight group (17.24±1.45). However, the overweight group was not significantly different from the normal weight or the obesity group for total and arm MBR. The total, arm, and leg SBR was significantly different between all BMI groups. Across the entire sample, MBR and SBR were negatively associated with high-density lipoprotein. SBR was positively associated with insulin, HOMA-IR, low-density lipoprotein, very low-density lipoprotein, triglycerides, and systolic blood pressure. CONCLUSIONS: Children with obesity had a higher MBR and SBR compared to their normal weight peers. In addition, there were significant associations between SBR, higher levels of insulin, atherogenic lipoproteins, and increased systolic blood pressure. Thus, SBR may be useful as a marker for increased cardiometabolic disease risk, though more research in this area is warranted.

Recreational screen time trajectories during early childhood and imaging-measured body composition at age 7 in the Odense child cohort.

BACKGROUND: Children spend increasing amounts of time on recreational screen media, which may lead to an obesogenic environment. OBJECTIVES: We investigated the association of trajectories of screen time across ages 3, 5 and 7 years with body composition at age 7 in the Odense Child Cohort. METHODS: Data were collected in the Municipality of Odense, Denmark, between 2010 and 2019. Group-based trajectory modelling was applied to group participants into four trajectories of prospective parent-reported screen time. Body composition was assessed using dual-energy x-ray absorptiometry with calculated fat-mass index (FMI) as the primary outcome. Primary models were linear multivariable regression models adjusted for participants' sex, age, birthweight, maternal origin, maternal education, maternal body-mass-index, and maternal age. Further models were adjusted for additional possible confounders. Selection bias was addressed by inverse probability weighting. RESULTS: In total, 803 children (48.2% female) were included in the primary analysis. Participants with screen time at all time points were assigned to four trajectory groups [constant low screen time (12.7%), low increase (36.3%), high increase between ages 3 and 5 (33.5%) and high increase in screen time (17.5%)]. Sample characteristics differed across missing data status and trajectories. Mean FMI (kg/m2 ) and standard deviation (SD) were 3.7 (SD 1.3) and 3.9 (SD 1.6) for the constant low versus high screen time, respectively. No differences in FMI were found between screen time trajectory groups at age 7 (adjusted mean difference 0.1 kg/m2 , 95% confidence interval -0.3, 0.5 for constant low versus high screen time). No consistent associations between screen time groups and secondary body composition outcomes were found. CONCLUSIONS: Results from this study do not suggest that recreational screen time from age 3 to 7 years is associated with adiposity or other measures of body composition.