DXA scanning in clinical practice

Predictive factors for osteoporosis in adult spinal deformity patients

PURPOSE

This study aimed to identify predictive factors for femoral bone mineral density (BMD) in adult patients with spinal deformity and to establish cutoff values for detecting osteoporosis using preoperative computed tomography (CT) scans.

METHODS

A retrospective analysis was conducted on 90 patients with adult spinal deformity (ASD) who underwent preoperative bone density testing. Key parameters such as age, body mass index (BMI), and Hounsfield unit (HU) values from various vertebral levels were analyzed. Dual-energy X-ray absorptiometry (DXA) was used to measure BMD T-score, and HU values were measured at C2, C7, T8, T9, L1, L2, and L3.

RESULTS

Multivariate regression analyses identified BMI and HU at C2 as independent predictors of femoral T-score. The following predictive equation was developed: femoral T-score = - 5.178 + 0.053 × BMI + 0.006 × C2 HU (R2 = 0.50). The formula derived from these variables explained 50% of the variance in femoral T-score. Receiver operating characteristic analysis identified cutoff values for predicting osteoporosis as 281 for C2 HU and 22.9 for BMI. The areas under the curve were 0.751 and 0.638, respectively.

CONCLUSION

These findings suggest that HU values from preoperative CT scans can serve as reliable indicators of femoral T-score, offering an alternative to DXA in cases where DXA is unavailable or inaccurate due to factors like severe spinal degeneration. This approach could enhance the preoperative assessment of osteoporosis in ASD patients by facilitating more targeted use of DXA and improving overall clinical decision-making.

LEVEL OF EVIDENCE

IV.

Bone loss in young adults with HIV following antiretroviral therapy containing tenofovir disoproxil fumarate regimen using machine learning

Objective

Bone mineral density (BMD) monitoring, primarily relying on dual-energy X-ray absorptiometry (DEXA), remains inaccessible in resource-limited regions, making it difficult to promptly address bone loss in people with HIV (PWH) on long-term ART-containing TDF regimens and assess the prevalence of bone loss. Our objective is to identify the frequency of PWH experiencing bone loss after long-term ART with a TDF regimen and to develop a predictive model of HIV-infected high-risk populations containing TDF long-time ART, for providing more appropriate ART regimens for PWH in clinical practice, particularly in resource-limited settings.

Methods

Our study retrospectively screened PWH under long-term follow-up at Peking Union Medical College Hospital (PUMCH) from January 2000 to August 2024. These individuals were either treatment-naive or treatment-experienced and had been on containing TDF ART regimen for over 5 years. BMD was assessed using DEXA every 1-2 years in this center. We selected predictive factors utilizing machine learning methods, including Random Forest, XGBoost, LASSO regression, and logistic regression. The results were visualized using a nomogram.

Results

Our study enrolled a total of 232 PWH who have contained TDF ART regimens for more than 5 years. Twenty-five percent (58/232) of the patients experienced bone loss, primarily including osteopenia and osteoporosis. Further results showed that the LASSO regression model was the most suitable for the current dataset, based on a comparison of LASSO regression, Random Forest, XGBoost, and logistic regression models including age, gender, LPV/r, baseline CD4+ T count, baseline VL, baseline body weight, treatment-naïve TDF, ART duration, percentage of CD38+CD8+T, percentage of HLA-DR+CD8+ T, and CD4+/CD8+ ratio, with AUC values of 0.615, 0.507, 0.593, and 0.588, respectively. We identified age, gender, and LPV/r as the most relevant predictive factors associated with bone loss based on LASSO regression. Then the results were visualized and plotted in a nomogram.

Conclusion

Our study quantified the frequency and established a nomogram based on the LASSO regression model to predict bone loss in PWH on long-term containing TDF ART. The nomogram guides identifying individuals at high risk of bone loss due to prolonged TDF exposure. Clinicians can leverage the predicted risk to design personalized ART regimens at the initiation of therapy or to switch from TDF-containing to TDF-free regimens during treatment. This approach aims to reduce the incidence of bone loss, particularly in resource-limited settings.

Osteoporosis Evaluation by Radiofrequency Echographic Multispectrometry (REMS) in Primary Healthcare

Background/Objectives: Radiofrequency echographic multispectrometry (REMS) technology has emerged as a promising alternative for osteoporosis diagnosis. This non-ionising, portable and accessible method enables early detection of osteoporosis in primary healthcare settings. The aim of this study was to assess the effectiveness of REMS in evaluating osteoporosis within primary healthcare. Methods: Bone mineral density was assessed in 86 participants trough 172 scans of the lumbar spine and femur, using REMS technology in two Portuguese primary healthcare units in Guarda. Results: In the lumbar spine evaluation, 51.2% of the participants had osteopenia and 31.4% osteoporosis; in the femur evaluation, 43.0% had osteopenia and 34.9% osteoporosis. The data indicated a significant prevalence of bone fragility. The bone mineral density estimated by radiofrequency echographic multispectrometry showed good agreement with the clinical diagnosis, suggesting that this technology is effective in the early detection of osteoporosis. Conclusions: Bone densitometry using REMS method, performed by a radiographer in primary healthcare settings, offers a viable and innovative alternative for the effective detection of osteoporosis and osteopenia.

Selection of density standard and X-ray tube settings for computed digital absorptiometry in horses using the k-means clustering algorithm

BACKGROUND

In veterinary medicine, conventional radiography is the first-choice method for most diagnostic imaging applications in both small animal and equine practice. One direction in its development is the integration of bone density evaluation and artificial intelligence-assisted clinical decision-making, which is expected to enhance and streamline veterinarians' daily practices. One such decision-support method is k-means clustering, a machine learning and data mining technique that can be used clinically to classify radiographic signs into healthy or affected clusters. The study aims to investigate whether the k-means clustering algorithm can differentiate cortical and trabecular bone in both healthy and affected horse limbs. Therefore, identifying the optimal computed digital absorptiometry parameters was necessary.

METHODS AND RESULTS

Five metal-made density standards, made of pure aluminum, aluminum alloy (duralumin), cuprum alloy, iron-nickel alloy, and iron-silicon alloy, and ten X-ray tube settings were evaluated for the radiographic imaging of equine distal limbs, including six healthy limbs and six with radiographic signs of osteoarthritis. Density standards were imaged using ten combinations of X-ray tube settings, ranging from 50 to 90 kV and 1.2 to 4.0 mAs. The relative density in Hounsfield units was firstly returned for both bone types and density standards, then compared, and finally used for clustering. In both healthy and osteoarthritis-affected limbs, the relative density of the long pastern bone (the proximal phalanx) differed between bone types, allowing the k-means clustering algorithm to successful differentiate cortical and trabecular bone.

CONCLUSION

Density standard made of duralumin, along with the 60 kV, 4.0 mAs X-ray tube settings, yielded the highest clustering metric values and was therefore considered optimal for further research. We believe that the identified optimal computed digital absorptiometry parameters may be recommended for further researches on the relative quantification of conventional radiographs and for distal limb examination in equine veterinary practice.

How does overweight affect bone mineral density and oral health in adult hypophosphatasia?- A single center experience

AIM

The aim of this study was to investigate the influence of overweight (BMI ≥ 25 (kg/m²)) on the oral health status in patients with adult hypophosphatasia (HPP).

MATERIALS AND METHODS

Throughout a retrospective assessment both oral health status and bone metabolism including dual x-ray absorptiometry (DXA) for bone mineral density (BMD) measures were analyzed. The oral health status was assessed by the decayed/missing/filled teeth index (DMFT), clinical attachment level (CAL), probing pocket depth (PPD), and the periodontal screening index (PSI). The study population was divided into two groups based on the overweight classification by BMI (Overweight = BMI ≥ 25 kg/m²; n = 17) vs. non-overweight ( BMI < 25 kg/m²; n = 31).

RESULTS

48 HPP patients were included in this study. Overweight HPP patients showed a significantly reduced oral health status regarding filled teeth, DMFT, PSI, PPD and periodontitis severity index compared to non-overweight HPP patients. Furthermore, overweight HPP patients revealed significantly higher DXA findings regarding BMD, T- and Z-scores.

CONCLUSION

In the present study overweight (BMI ≥ 25 (kg/m²)) is associated with a poorer oral health status and higher BMD in adult HPP.

CLINICAL RELEVANCE

Since overweight is associated with a poorer oral health status in the general population and promotes the development of periodontal disease, the findings of the present study indicate that overweight also affects oral health in adult HPP.

Relationship between bone mineral density and oral health: a cross sectional observational study

PURPOSE

Bone mineral density (BMD) is related to oral health. This study investigated how changes in BMD influence tooth loss risk and dental caries prevalence.

METHODS

This cross-sectional observational study included 224 people (199 males and 25 females). The BMD scores of the participants' lumbar spine, femoral neck, and total hip were categorized as normal, osteopenia, or osteoporosis. Oral health was assessed using the Decayed, Missing, Filled Teeth (DMFT) index and Oral Hygiene Index-Simplified (OHI-S) scores. Based on the number of surviving teeth, the participants were categorized into low (< 20) and high (≥ 20) groups. Differences between groups were assessed using independent sample T tests and one-way analysis of variance.

RESULTS

The normal, osteopenia, and osteoporosis groups comprised 72, 87, and 65 participants, respectively. The OHI-S scores showed no notable variations across the groups. The DMFT index scores were highest (18.69) in the osteoporosis group and lowest (14.08) in the normal group (p < 0.001). Although the number of remaining teeth was lower in the osteoporosis and osteopenia groups compared to the normal group (p < 0.001), that in the osteopenia group approximated the normal group, but was substantially higher than in the osteoporosis group. The group with the lowest number of remaining teeth had lower total hip T-scores, despite significantly higher DMFT indexes (p < 0.001).

CONCLUSIONS

Tooth loss and dental decay rates were significantly high in patients with osteoporosis. Although bone resorption during osteopenia is not excessive, it constitutes a crucial risk factor for dental health. Therefore, attention must be paid to bone resorption treatment in patients with osteopenia.

Evaluation of Bone Mineral Metabolism in Pre-Dialysis Chronic Kidney Disease: Quantitative Computed Tomography vs. Dual-Energy Absorptiometry and Correlation with Bone Turnover Markers

Background and Objectives: Bone and mineral disease (BMD) is a prevalent complication of advanced chronic kidney disease (CKD). The risk of fractures can be assessed via dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). This study aims to evaluate the effectiveness of two imaging modalities in identifying bone mineral status in individuals with pre-dialysis chronic renal disease and to assess their correlation with bone turnover markers. Materials and Methods: This controlled cross-sectional study, conducted at a single center from 2019 to 2022, assessed two groups of individuals aged 18 to 50. The patient cohort consisted of individuals with stage 4-5 chronic kidney disease, whereas the control cohort consisted of healthy participants. The participants' bone and mineral status was evaluated using both QCT and DXA methods. Diagnostic measurements of the lumbar spine and femoral neck, obtained using DXA and QCT, were compared. Z-scores were utilized to evaluate low bone mineral density, with low Z-scores identified in either lumbar spine or femoral neck measures being seen as indicative of low bone mineral density. Results: Data from 38 participants (patient group: 18; control group: 20) who underwent QCT and/or DXA were evaluated. Thirty-three subjects were assessed using both QCT and DXA (patient group: 14; control group: 19). The median age of the patient cohort was 44 (range: 22-50), whereas the median age of the control cohort was 42 (range: 27-48) (p = 0.72). Women constituted 33% of the patient cohort and 50% of the control cohort (p = 0.23). In the patient cohort, low bone mineral density was detected in four individuals (28%) through QCT, and in just two patients (14%) through DXA. Compared to DXA, QCT identified a higher number of cases of low bone mineral density in the CKD cohort; however, no statistically significant difference was observed (p = 0.06). In addition, our study found that TRACP5b had a strong negative correlation with the DXA L1-L4 Z-score. Conclusions: This study revealed that QCT may be more sensitive than DXA for detecting low bone density in pre-dialysis CKD patients. Additionally, DXA may overestimate lumbar spine BMD in this population, and the strong negative correlation between TRACP5b levels and the DXA L1-L4 Z-score highlights the potential role of biochemical markers in assessing bone status in CKD.

Self-Assembled Nanoparticles with Well-Defined Oligosaccharide Promote Osteogenesis by Regulating Golgi Stress Response

Osteoporosis, a prevalent disease characterized by low bone density and increased fracture risk, poses significant health challenges for the elderly. Current treatments offer short-term benefits but are limited by long-term efficacy and adverse effects, highlighting the need for new strategies. Chondroitin sulfate polysaccharides (CS), a major component of the bone matrix, are crucial for bone and cartilage health. However, their role in osteoporosis is understudied due to the heterogeneity of natural CS. we found reduced CS levels in osteoporosis patients and developed CS4-NP, a self-assembled tetrasaccharide nanoparticle that mimics CS's structure. CS4-NP, which efficiently delivers the active CS4, significantly improves bone mass in ovariectomized osteoporosis models. It activates the Activating Transcription Factor 4-Cystathionine gamma-Lyase signaling axis in pre-osteoblasts, enhancing osteogenesis. our findings suggest that CS4-NP, an oligosaccharide-based nanomaterial, could address the limitations of current treatments and provide a viable strategy for osteoporosis.

Lumbar Spine Densitometry in People with Spinal Cord Injury: Investigation of Potential Sources of Errors

PURPOSE

People with spinal cord injury (SCI) experience a considerable loss of bone after the injury. Lumbar spine (LS) bone mineral density (BMD) has been reported to be within the normal range, or even higher when assessed with DXA, in people with SCI; hence, it has been hypothesized that sources of error may spuriously increase LS BMD. The aim of this study was to describe the frequency of potential sources of error that may alter LS BMD measurement in a cohort of individuals with chronic SCI at baseline and over a 2-year period.

METHODS

We analyzed baseline and 2-year follow up DXA scans (Hologic Discovery QDR 4500, Hologic Inc., MA, USA) previously performed from a cohort of males and females with chronic SCI. Two physicians independently reviewed each scan, commented on whether the scan was appropriate for BMD analysis, should be re-analyzed, or be removed from the dataset, and reported on the presence of potential sources of error in LS BMD measurement.

RESULTS

We reviewed 115 lumbar spine DXA scans from 58 participants, and 107 (93.0 %) scans from 52 participants presented at least one potential source of error. At baseline, the average number of potential sources of error per scan was 5.5 ± 1.7 and 5.7 ± 1.5 according to rater 1 and rater 2, respectively. Follow-up scans presented an average of 5.6 ± 1.6 and 5.7 ± 1.4 potential sources of error according to rater 1 and rater 2, respectively. Facet sclerosis, osteophytes and difficulty in detecting bone edges were the most prevalent sources of error.

CONCLUSION

The high frequency of potential sources of error is consistent with current recommendations against the use of LS BMD for fracture risk assessment in people with SCI.

Role of PLP-Level as a predictive marker for oral health status in adult hypophosphatasia

AIM

The aim of this study was to investigate the role of pyridoxal-5-phosphate (PLP) level on the oral health status as a predictive marker in patients with hypophosphatasia (HPP).

MATERIALS AND METHODS

Throughout a systematic retrospective assessment both bone metabolism and oral health status were analyzed. The oral health status was assessed by the decayed/missing/filled teeth index (DMFT), clinical attachment level (CAL), probing pocket depth (PPD), and the periodontal screening index (PSI).

RESULTS

A total of 48 HPP patients (81.3% female) with a mean age of 42.21 years was included in this retrospective study. The study population was divided into two groups using the mean PLP level (87 µg/l) as a cut-off. Patients with a PLP level ≥ 87 µg/l (n = 14) showed a significantly poorer oral health status regarding DMFT index, CAL, PPD and PSI compared to patients with a PLP level < 87 µg/l (n = 34). No significant group differences for tooth loss were found.

CONCLUSION

The results of the present study indicate that the PLP level is a suitable diagnostic predictor for the oral health status in HPP patients. HPP patients with PLP levels ≥ 70 µg/l should be included into a regular dental preventive program.

CLINICAL RELEVANCE

The oral health status in HPP and its correlation with laboratory parameters (i.e. PLP) has been understudied. For clinical practice, the findings of the present study clearly demonstrated that high PLP levels correlate with a worse oral health status in HPP patients. Therefore, these patients should receive an intensive dental treatment and/or inclusion in a strict maintenance program in a specialized dental practice/university hospital with a PLP level ≥ 70 µg/l.

Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial

Importance

A major concern with weight loss is concomitant bone loss. Exercise and glucagon-like peptide-1 receptor agonists (GLP-1RAs) represent weight loss strategies that may protect bone mass despite weight loss.

Objective

To investigate bone health at clinically relevant sites (hip, spine, and forearm) after diet-induced weight loss followed by a 1-year intervention with exercise, liraglutide, or both combined.

Design, Setting, and Participants

This study was a predefined secondary analysis of a randomized clinical trial conducted between August 2016 and November 2019 at the University of Copenhagen and Hvidovre Hospital in Denmark. Eligible participants included adults aged 18 to 65 years with obesity (body mass index of 32-43) and without diabetes. Data analysis was conducted from March to April 2023, with additional analysis in February 2024 during revision.

Interventions

After an 8-week low-calorie diet (800 kcal/day), participants were randomized to 1 of 4 groups for 52 weeks: a moderate- to vigorous-intensity exercise program (exercise alone), 3.0 mg daily of the GLP-1 RA liraglutide (liraglutide alone), the combination, or placebo.

Main Outcomes and Measures

The primary outcome was change in site-specific bone mineral density (BMD) at the hip, lumbar spine, and distal forearm from before the low-calorie diet to the end of treatment, measured by dual-energy x-ray absorptiometry in the intention-to-treat population.

Results

In total, 195 participants (mean [SD] age, 42.84 [11.87] years; 124 female [64%] and 71 male [36%]; mean [SD] BMI, 37.00 [2.92]) were randomized, with 48 participants in the exercise group, 49 participants in the liraglutide group, 49 participants in the combination group, and 49 participants in the placebo group. The total estimated mean change in weight losses during the study was 7.03 kg (95% CI, 4.25-9.80 kg) in the placebo group, 11.19 kg (95% CI, 8.40-13.99 kg) in the exercise group, 13.74 kg (95% CI, 11.04-16.44 kg) in the liraglutide group, and 16.88 kg (95% CI, 14.23-19.54 kg) in the combination group. In the combination group, BMD was unchanged compared with the placebo group at the hip (mean change, -0.006 g/cm2; 95% CI, -0.017 to 0.004 g/cm2; P = .24) and lumbar spine (-0.010 g/cm2; 95% CI, -0.025 to 0.005 g/cm2; P = .20). Compared with the exercise group, BMD decreased for the liraglutide group at the hip (mean change, -0.013 g/cm2; 95% CI, -0.024 to -0.001 g/cm2; P = .03) and spine (mean change, -0.016 g/cm2; 95% CI, -0.032 to -0.001 g/cm2; P = .04).

Conclusions and Relevance

In this randomized clinical trial, the combination of exercise and GLP-1RA (liraglutide) was the most effective weight loss strategy while preserving bone health. Liraglutide treatment alone reduced BMD at clinically relevant sites more than exercise alone despite similar weight loss.

Trial Registration

EudraCT: 2015-005585-32.

Bone Mineral Density in Mountain, Road Cyclists and Untrained Controls: Exercise, Diet and Hormones

Purpose: The aim of the study was to compare bone mineral density (BMD) in the lumbar spine (LSBMD) and the femoral neck (FBMD) in male road cyclists (RC n = 39), mountain cyclists (MC n = 30) and controls (C n = 27) and to determine the factors associated with BMD in the same group of participants. Methods: BMD, fat mass (FM) and fat-free mass (FFM) were measured using DXA. Calcium intake (Cal), exercise energy expenditure (EEE) and energy availability (EA) were assessed using self-reported questionnaires. Samples for circulating hormones were also obtained. VO2max was estimated by a cycloergometric test. Results: After adjustment for body mass, in cyclists LSBMD (RC 0.98 ± 0.12; MC 0.98 ± 0.10 g/cm2) was significantly lower than in C (1.11 ± 0.10; p < .001), while FBMD resulted in no significant difference in cyclists compared to C (p = 0.213). EA (kcal/FFM/day) was different in cyclists and in C (p < .05). In C, EEE and EA were positively associated with LSBMD (R = 0.561, R = 0.656, respectively, p < .01), whereas only EA was associated with FBMD (R = 0.554, p < .05); a positive association between EA and FBMD was found in MC (R = 0.464, p < .05). A negative relationship between VO2max and LSBMD in RC (R = -0.418, p < .05) and a positive one between EEE and LSBMD in MC were found (R = 0.605, p < .001). CaI, free testosterone and cortisol were unrelated to BMD. Conclusion: Both the RC and MC had lower LSBMD than C, whereas no difference was found between the two groups of cyclists. The factors associated with BMD are manifold, vary in relation to the measurement site and are likely different in RC, MC and C.

Does the proximal humeral bone quality influence alignment after reverse total shoulder arthroplasty with short humeral stems?

PURPOSE

When compared to standard-length humeral stem in reverse total shoulder arthroplasty (RTSA), short humeral stems in RTSA require good proximal humeral metaphyseal bone quality to gain proper and secure fixation during prosthetic implantation. Shorter humeral stems potentially carry more risk of misalignment than standard or long humeral stems. The hypothesis was that misalignment of the short humeral stems is influenced by regional bone quality.

METHODS

RTSA with a short curved humeral stem with neck-shaft angle (NSA) default of 132.5° was reviewed. The study group included 35 cases at a mean age of 75.97 (± 6.23) years. Deltoid-tuberosity index (DTI) was measured to evaluate proximal humeral bone quality. The deltoid tuberosity index was measured at immediately above position of the upper end of the deltoid tuberosity. Stem alignment was given by the angle measured in degrees between the intramedullary humeral shaft axis and the axis of the humeral implant stem.

RESULTS

The patient's mean DTI was 1.37 ± 0.16 (median, 1.32; range, 1.12-1.80). 22 patients had poor bone quality (DTI < 1.4), compared to 13 patients with acceptable bone quality (DTI > 1.4). After RTSA, ten humeral components (29%) were neutrally aligned, whereas 25 humeral components (71%) were misaligned. There was no correlation between misalignment and DTI (r = 0.117; p = 0.504). But there was a strong correlation between misalignment and the patient's own NSA (r = - 0.47; p = 0.004). The postoperative stem position and stem misalignment are not associated with functional outcomes (p > 0.05).

CONCLUSION

The misalignment of the short curved humeral stem frequently occurs. Poor reginal humeral bone quality does not influence misalignment after RTSA with a short humeral stem. Postoperative stem alignment is associated with the patient's preoperative NSA and method of neck cut. The misalignment does not affect functional outcomes for midterm follow-up. Further long-term follow-up studies are needed to confirm its clinical relevance.

State of the Art Imaging of Osteoporosis

Osteoporosis is a common disease, particularly prevalent in geriatric populations, which causes significant worldwide morbidity due to increased bone fragility and fracture risk. Currently, the gold-standard modality for diagnosis and evaluation of osteoporosis progression and treatment relies on dual-energy x-ray absorptiometry (DXA), which measures bone mineral density (BMD) and calculates a score based upon standard deviation of measured BMD from the mean. However, other imaging modalities can also be used to evaluate osteoporosis. Here, we review historical as well as current research into development of new imaging modalities that can provide more nuanced or opportunistic analyses of bone quality, turnover, and density that can be helpful in triaging severity and determining treatment success in osteoporosis. We discuss the use of opportunistic computed tomography (CT) scans, as well as the use of quantitative CT to help determine fracture risk and perform more detailed bone quality analysis than would be allowed by DXA . Within magnetic resonance imaging (MRI), new developments include the use of advanced MRI techniques such as quantitative susceptibility mapping (QSM), magnetic resonance spectroscopy, and chemical shift encoding-based water-fat MRI (CSE-MRI) to enable clinicians improved assessment of nonmineralized bone compartments as well as a way to longitudinally assess bone quality without the repeated exposure to ionizing radiation. Within ultrasound, development of quantitative ultrasound shows promise particularly in future low-cost, broadly available screening tools. We focus primarily on historical and recent developments within radiotracer use as applicable to osteoporosis, particularly in the use of hybrid methods such as NaF-PET/CT, wherein patients with osteoporosis show reduced uptake of radiotracers such as NaF. Use of radiotracers may provide clinicians with even earlier detection windows for osteoporosis than would traditional biomarkers. Given the metabolic nature of this disease, current investigation into the role molecular imaging can play in the prediction of this disease as well as in replacing invasive diagnostic procedures shows particular promise.

Pharmacological prevention of bone loss and fractures following solid organ transplantations: Protocol for a systematic review and network meta-analysis

INTRODUCTION

Solid organ transplant (SOT) recipients can experience bone loss caused by underlying conditions and the use of immunosuppressants. As a result, SOT recipients are at risk for decreased bone mineral density (BMD) and increased fracture incidences. We propose a network meta-analysis (NMA) that incorporates all available randomized control trial (RCT) data to provide the most comprehensive ranking of anti-osteoporotic interventions according to their ability to decrease fracture incidences and increase BMD in SOT recipients.

METHODS

We will search MEDLINE, EMBASE, Web of Science, CINAHL, CENTRAL and CNKI for relevant RCTs that enrolled adult SOT recipients, assessed anti-osteoporotic therapies, and reported relevant outcomes. Title and full-text screening as well as data extraction will be performed in-duplicate. We will report changes in BMD as weighted or standardized mean differences, and fracture incidences as risk ratios. SUCRA scores will be used to provide rankings of interventions, and quality of evidence will be examined using RoB2 and CINeMA.

DISCUSSIONS

To our knowledge, this systematic review and NMA will be the most comprehensive quantitative analysis regarding the management of bone loss and fractures in SOT recipients. Our analysis should be able to provide physicians and patients with an up-to-date recommendation for pharmacotherapies in reducing incidences of bone loss and fractures associated with SOT. The findings of the NMA will be disseminated in a peer-reviewed journal.

Pediatric and adult osteoporosis: a contrasting mirror

Pediatric osteoporosis (PO) is a condition that is currently gaining recognition. Due to the lack of official definitions over the past few decades, the exact incidence of PO is unknown. The research does not provide a specific prevalence of PO in different world regions. However, this is expected to change with the latest 2019 guidelines proposed by the International Society of Clinical Densitometry. Although adult osteoporosis (AO) has been postulated a pediatric disease because its manifestation in adulthood is a result of the bone mass acquired during childhood, differences between PO and AO should be acknowledged. AO is defined as low bone density; however, PO is diagnosed based on existing evidence of bone fragility (vertebral fractures, pathological fractures). This is particularly relevant because unlike in adults, evidence is lacking regarding the association between low bone density and fracture risk in children. The enhanced capacity of pediatric bone for reshaping and remodeling after fracture is another difference between the two entities. This contrast has therapeutic implications because medication-free bone reconstitution is possible under certain conditions; thus, background therapy is not always recommended. In this narrative review, differences between PO and AO in definition, assessment, and medical approach were investigated.

Fragility spinal fractures among cirrhotic liver transplant candidates in Croatia

INTRODUCTION

Existing data on fragility spinal fractures prevalence in liver transplant candidates are scarce and inconsistent. This may be due to other comorbidities, besides hepatic osteodystrophy (HO), that contribute to bone loss and fragility fracture prevalence in chronic liver disease (CLD).

OBJECTIVES

The aim of this study was to investigate the prevalence of spinal thoracic and lumbar fragility fractures among cirrhotic, non-chronic kidney disease (CKD), non-diabetic liver transplant candidates and to explore their relationship with clinical characteristics, laboratory markers and dual-energy x-ray absorptiometry (DXA) results.

MATERIAL AND METHODS

This cross-sectional observational study was conducted at Merkur University Hospital, Croatia, between February 2019 and May 2023. Adult patients with liver cirrhosis referred for liver transplantation were included. Patients with acute infection, CKD, diabetes mellitus, malignancies, inflammatory bone diseases and those on corticosteroid or antiresorptive therapy were excluded. Clinical, laboratory and radiological assessment was carried out and patients were accordingly allocated into non-fractured and fractured group for the purpose of statistical analysis.

RESULTS

A total of 90 patients were included in the study. There was 123 fractures, 87 (70.7 %) in the thoracic and 36 (29.3 %) in the lumbar region. Eighty-nine (72.4 %) fractures were grade 1, 31 (25.2 %) were grade 2 and 3 (2.4 %) were grade 3. Patients in the fractured group were significantly older (p < 0.001). No significant differences between fractured and non-fractured group according to laboratory and DXA parameters were noted. Subgroup with lumbar fractures had significantly lower bone mineral density values at L1-L4 region. Statistically significant negative correlation between bone specific alkaline phosphatase (BALP) and hip total BMD (rho = -0.414, p < 0.001) and spine total BMD (rho = -0.258, p = 0.014) values was found.

CONCLUSION

Present study confirmed detrimental impact of CLD and HO on bone strength. DXA measurement correlated with the presence of lumbar fragility fractures. A combination of standard X-ray imaging and DXA is needed for adequate bone evaluation in pretransplant period and BALP could be useful for detecting HO in CLD. Searching for other risk factors and implementing bone turnover markers and additional imaging techniques for bone loss evaluation in liver transplant candidates is needed.

Osteoporosis Prediction Using Machine-Learned Optical Bone Densitometry Data

Optical bone densitometry (OBD) has been developed for the early detection of osteoporosis. In recent years, machine learning (ML) techniques have been actively implemented for the areas of medical diagnosis and screening with the goal of improving diagnostic accuracy. The purpose of this study was to verify the feasibility of using the combination of OBD and ML techniques as a screening tool for osteoporosis. Dual energy X-ray absorptiometry (DXA) and OBD measurements were performed on 203 Thai subjects. From the OBD measurements and readily available demographic data, machine learning techniques were used to predict the T-score measured by the DXA. The T-score predicted using the Ridge regressor had a correlation of r = 0.512 with respect to the reference value. The predicted T-score also showed an AUC of 0.853 for discriminating individuals with osteoporosis. The results obtained suggest that the developed model is reliable enough to be used for screening for osteoporosis.

Clinical Characteristics and Therapeutic Management of Osteogenesis Imperfecta in Iraqi Children

Background: Osteogenesis imperfecta (OI) is a rare congenital condition that results in bone fragility, recurrent fractures, and various extra-skeletal manifestations. Currently, intravenous bisphosphonate is the mainstay of medical treatment in OI. Objective: To identify the effect of current management strategies on Iraqi children diagnosed with OI. Methods: A retrospective study enrolled OI patients who were registered in Central Child Teaching Hospital, Baghdad, Iraq, from January 2015 to December 2022. We enrolled confirmed OI cases (either clinically and/or radiologically) who received cyclic pamidronate therapy for at least 3 cycles. They neither received other types of bisphosphonates nor underwent surgical intervention. Results: A total of 52 cases of OI had been identified, but only 36 patients were eligible for the current study. The mean age of the patients was 6.64±4.22 years. A statistically significant drop in the annual fracture rate in OI patients who received intravenous pamidronate cycles was seen, along with a significant rise in weight for age Z-score, lumbar spine bone mineral density DEXA Z-score, and alkaline phosphate levels. No significant improvement was documented in height for age Z-score in OI patients. Conclusions: Intravenous pamidronate cycles for Iraqi children with osteogenesis imperfecta work to lower their risk of breaking bones every year and raise their weight, lumbar spine bone mineral density, and alkaline phosphate levels. Pamidronate did not result in an improvement in the height of OI children.

FR. DEXA and Imaging in Osteoporosis

Background

Reduced bone density and increased fragility are hallmarks of osteoporosis, making the disease a major public health concern. The disease necessitates early diagnosis and appropriate therapy depend on an accurate evaluation of bone health. Essential tools for assessing osteoporosis include dual-energy X-ray absorptiometry (DEXA) and other imaging modalities.

Methods

This chapter focuses on dual-energy X-ray absorptiometry (DEXA) and other imaging methods as essential tools for assessment of osteoporosis. The chapter also explores complementary imaging modalities that help overcome limitation of DEXA by providing insights into the microarchitecture and bone quality.

Results

T-scores, used to categorise bone health, are determined by DEXA by comparing bone mineral density to age-matched standards. Bone mineral density (BMD) is the most common indicator of bone health; nevertheless, DEXA may misclassify bone health owing to reasons other than BMD. These constraints may be overcome with the use of complementary imaging methods, which provide information on the microarchitecture and quality of bone. The evaluation of bone structure is aided by high-resolution peripheral quantitative computed tomography (HR-pQCT), which produces precise 3D images of the trabecular and cortical bone compartments. Independent of traditional methods of gauging fracture risk, quantitative ultrasonography (QUS) uses an analysis of the characteristics of sound waves to determine bone health. Diagnostic precision is improved by magnetic resonance imaging (MRI) due to its ability to view bone marrow and trabecular structure without the use of ionising radiation.

Discussion

New methods, such as the trabecular bone score (TBS), examine bone texture and provide more data on the likelihood of fracture than conventional DEXA. By modelling bone strength using imaging data, finite element analysis (FEA) provides a biomechanical viewpoint on breakage probability. These combined methods boost diagnostic accuracy and pave the way for individualised treatment plans. Imaging helps with therapy monitoring as well as diagnosis. By monitoring bone density and structure over time, therapy effectiveness or course corrections may be quickly identified. The availability of sophisticated imaging techniques and the standardisation of procedures provide obstacles not withstanding their advantages. Ongoing work is being done to solve these issues and standardise and disseminate these methods in a variety of contexts.

Conclusion

The evaluation of osteoporosis is significantly aided by DEXA and other imaging methods. While DEXA is still the gold standard for diagnosing osteoporosis, other imaging techniques may shed light on bone health in greater detail. These methods improve fracture risk prediction and treatment assessment by providing information on bone architecture, quality, and strength. Integration of several imaging modalities shows potential for bettering osteoporosis therapy and patient outcomes as the field develops.

The Use of Bone Density Scan in Monitoring Treatment Response in Patients Diagnosed with Osteoporosis: A Retrospective Cohort Study

Osteoporosis is characterized as a metabolic bone disease defined by low bone mineral density (BMD) and bone tissue degeneration, particularly a reduction in the number of trabeculae and a drop in cortical bone thickness, and a rise in porosity, which is mainly due to an imbalance between bone resorption and formation. As a result, it increases bone fragility, and the susceptibility to fracture increases, especially among the elderly. The objective is to assess the effectiveness of dual-energy X-ray absorptiometry (DXA) scan in monitoring the response to osteoporosis treatment and compare the scan's response to different osteoporosis treatments. This retrospective cohort study included 51 adults selected from 300 patients diagnosed with osteoporosis based on World Health Organization (WHO) diagnostic criteria of a T-score of -2.5. Data were acquired from the electronic medical records between 2016 and 2019 from a private hospital in Dubai, United Arab Emirates (UAE). The study included sociodemographic characteristics, biomedical parameters, comorbidities, history of fracture, medications, laboratory, and DXA scan results. Ninety-four percent of the patients were females; the mean (±SD) age was 58.1 ± 11.5 years. Most patients were expatriates (84.3%), of which Asian ethnicity was 66.7%. The mean (±SD) duration of osteoporosis was 2.82 ± 1.8 years. Eleven (21.6%) patients had a history of fragility fracture. Ninety-six percent of the patients had vitamin D deficiency. One-third (29.4%) of the patients had hyperparathyroidism. Alendronate/cholecalciferol, received by nine patients (17.6%), showed a significant improvement (p = 0.018) in the BMD of the femoral neck among the study group. In conclusion, the DXA scan as a monitoring tool has shown a significant improvement in the BMD of the femoral neck among patients taking alendronate/cholecalciferol treatment compared to other medications.

Enhancement of Hip X-ray with Convolutional Autoencoder for Increasing Prediction Accuracy of Bone Mineral Density

It is very important to keep track of decreases in the bone mineral density (BMD) of elderly people since it can be correlated with the risk of incidence of major osteoporotic fractures leading to fatal injuries. Even though dual-energy X-ray absorptiometry (DXA) is the one of the most precise measuring techniques used to quantify BMD, most patients have restricted access to this machine due to high cost of DXA equipment, which is also rarely distributed to local clinics. Meanwhile, the conventional X-rays, which are commonly used for visualizing conditions and injuries due to their low cost, combine the absorption of both soft and bone tissues, consequently limiting its ability to measure BMD. Therefore, we have proposed a specialized automated smart system to quantitatively predict BMD based on a conventional X-ray image only by reducing the soft tissue effect supported by the implementation of a convolutional autoencoder, which is trained using proposed synthesized data to generate grayscale values of bone tissue alone. From the enhanced image, multiple features are calculated from the hip X-ray to predict the BMD values. The performance of the proposed method has been validated through comparison with the DXA value, which shows high consistency with correlation coefficient of 0.81 and mean absolute error of 0.069 g/cm2.

Improving DXA Quality by Avoiding Common Technical and Diagnostic Pitfalls: Part 1

Dual-energy x-ray absorptiometry (DXA) is an accurate means to assess bone mineral density, determine the risk of a fragility fracture, and monitor response to therapy. Despite its seemingly straightforward nature-the review of 2-to-3 nondiagnostic images and a few automatically generated numbers-the proper performance and interpretation of DXA can often be complex. It is complex because it is highly dependent on many factors, such as image acquisition, processing, analysis, and subsequent examination interpretation. Each step is subject to potential errors, artifacts, and diagnostic pitfalls; hence, meticulous attention must be paid to the technique by both the technologist and the interpreting physician to provide high-quality results and, in turn, maximize the examination's clinical utility. This article is part 1 of a 2-part series. Part 1 will begin with a review of bone physiology and osteoporosis etiology, followed by a discussion of the principles underlying DXA and the technical procedure. Part 2 will focus on DXA interpretation and discuss scanning pitfalls and clues to recognizing issues and improving scan quality.

Age, body composition parameters and glycaemic control contribute to trabecular bone score deterioration in acromegaly more than disease activity

Introduction

Impairment of bone structure in patients with acromegaly (AP) varies independently of bone mineral density (BMD). Body composition parameters, which are altered in patients with acromegaly, are important determinants of bone strength.

Purpose

The aim of this study was to examine BMD and lumbar trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) and to assess its relationship with disease activity, age, glucose metabolism, and body composition parameters.

Methods

This cross-sectional prospective study involved 115 patients with acromegaly (70 F, 45 M) and 78 healthy controls (CON) (53 F, 25 M) matched for age, gender, and BMI. Bone mineral density, TBS and body composition parameters were measured using DXA.

Results

AP presented with lower TBS compared to CON (1.2 ± 0.1 v 1.31 ± 0.1, P< 0.001). No significant correlation was observed between IGF-1/GH levels and TBS. Age, glycated haemoglobin, BMI, waist circumference, fat mass, and lean mass negatively correlated with TBS in both sexes. Multiple linear regression analysis of all these parameters revealed age and waist circumference as independent significant predictors of TBS in AP. We did not find difference in BMD (lumbar and femoral sites) between AP and CON nor between active and controlled AP. We observed negative correlation between age and BMD of the femoral neck and total hip (P < 0.001). Testosterone levels in males, BMI, waist circumference, fat mass, and lean mass positively correlated with BMD in AP, with stronger correlation between lean mass and BMD compared to fat mass.

Conclusion

Patients with acromegaly have lower TBS than controls, confirming impaired bone microarchitecture in acromegaly regardless of BMD. Age, body composition parameters and glucose metabolism contribute to TBS deterioration in AP more than disease activity itself.

Preoperative medical assessment for adult spinal deformity surgery: a state-of-the-art review

INTRODUCTION

The purpose of this study is to provide a state-of-the-art review regarding risk factors for perioperative complications in adult spinal deformity (ASD) surgery. The review includes levels of evidence for risk factors associated with complications in ASD surgery.

METHODS

Using the PubMed database, we searched for complications, risk factors, and adult spinal deformity. The included publications were assessed for level of evidence as described in clinical practice guidelines published by the North American Spine Society, with summary statements generated for each risk factor (Bono et al. in Spine J 9:1046-1051, 2009).

RESULTS

Frailty had good evidence (Grade A) as a risk for complications in ASD patients. Fair evidence (Grade B) was assigned for bone quality, smoking, hyperglycemia and diabetes, nutritional status, immunosuppression/steroid use, cardiovascular disease, pulmonary disease, and renal disease. Indeterminate evidence (Grade I) was assigned for pre-operative cognitive function, mental health, social support, and opioid utilization.

CONCLUSIONS

Identification of risk factors for perioperative complications in ASD surgery is a priority for empowering informed choices for patients and surgeons and managing patient expectations. Risk factors with grade A and B evidence should be identified prior to elective surgery and modified to reduce the risk of perioperative complications.

Comparison of bone mineral density changes between male and female osteoporosis patients using dual energy X-ray absorptiometry scan

The goal of the current research was to define the impact of individual characteristics on the response of osteoporosis patients to bisphosphonate medication, as well as the influence of gender on changes in the bone mineral density (BMD).The DXA scan was used to assess a group of 647 osteoporosis patients (533 females and 114 males) who visited the St Bartholomew's Hospitals and Royal London osteoporosis clinics. All male subjects received statistically substantial increases in BMD relative to baseline values after two years of therapy. When compared to prior therapy, men's BMD of the lumbar spine (LS) and hip joint (HJ) rose by 0.057 g/cm² (6.9%, p0.001) and 0.021 g/cm² (2.48 percent, p0.001), respectively.. Female patients had BMD changes of 0.028 g/cm² (3.58 percent, p0.001 vs. prior therapy) and -0.006 g/cm² (-0.78 percent, p0.001 vs. before treatment) in the lumbar spine and hip, respectively. Male patients exhibited a greater increase in BMD than female patients due to ovarian failure and significant oestrogen loss, which speeds up bone resorption by 90% following menopause, according the research findings.

Femur 3D-DXA Assessment in Female Football Players, Swimmers, and Sedentary Controls

Cortical and trabecular volumetric bone mineral density (vBMD), cortical thickness and surface BMD (sBMD, density-to-thickness ratio) were analyzed in the proximal femur of elite female football players and artistic swimmers using three-dimensional dual-energy X-ray absorptiometry (3D-DXA) software and compared to sedentary controls. Football players had significantly higher (p<0.05) vBMD (mg/cm³) in the trabecular (263±44) and cortical femur (886±69) than artistic swimmers (224±43 and 844±89) and sedentary controls (215±51 and 841±85). Football players had also higher (p<0.05) cortical thickness (2.12±0.19 mm) and sBMD (188±22 mg/cm²) compared to artistic swimmers (1.85±0.15 and 156±21) and sedentary controls (1.87±0.16 and 158±23). Artistic swimmers did not show significant differences in any parameter analyzed for 3D-DXA when compared to sedentary controls. The 3D-DXA modeling revealed statistical differences in cortical thickness and vBMD between female athletes engaged in weight-bearing (football) and non-weight bearing (swimming) sports and did not show differences between the non-weight bearing sport and the sedentary controls. 3D-DXA modeling could provide insight into bone remodeling in the sports field, allowing evaluation of femoral trabecular and cortical strength from standard DXA scans.

Discrepancies Between Osteoporotic Fracture Evaluations in Men Based on German (DVO) Osteoporosis Guidelines or the FRAX Score

INTRODUCTION

Established scores estimate 10-year fracture risk in osteoporosis to assist with treatment recommendations. This study compared the risk probabilities of major osteoporotic and hip fractures calculated by the FRAX tool with those of the DVO score, established in German-speaking countries.

MATERIAL AND METHODS

This seven-year retrospective study analyzed data of 125 male patients (mean age: 59.2±10.7 years) evaluated for osteoporosis. For the DVO score, the therapy threshold of>30% for vertebral and hip fractures suggested by DVO guidelines was implemented. We calculated fracture risks based on FRAX scores with aBMD and applied a common therapy threshold of≥3% for hip fracture and subsequently determined the "DVO-equivalent risk level" for FRAX-based assessment that would identify as many male patients as identified by the DVO score.

RESULTS

Based on DVO score, 60.0% of patients had a 10-year risk of hip and vertebral fractures>30%. The recommendations for individuals based on FRAX scores for hip fracture with aBMD with risk≥3% overlapped with those based on DVO score in 36% of patients. Patients identified for treatment only by DVO score presented a higher percentage of spine fractures (65 vs. 41%). The thresholds for this "DVO-equivalent risk level" for 'FRAX with aBMD' was estimated to be≥6.7% for major osteoporotic fracture and≥2.1% for hip fracture.This study demonstrates that the DVO score was more sensitive than the FRAX score for patients with prevalent spinal fractures. We suggest considering the appropriate score and therapy threshold carefully in the daily care of male patients.

Biomechanical analysis analyzing association between bone mineral density and lag screw migration

A proximal femoral nail using a helical blade (HB) is commonly utilized to treat proximal femoral fracture but cut through failure of the lag screws is one of the devastating complications following the surgery. While controversial, one of the potential risk factors for cut through failure is poor bone strength which can be predicted by measuring bone mineral density (BMD). In this study, we performed a biomechanical test on the fractured femoral head to validate whether the indirectly measured BMD from the contralateral hip or that measured directly from the retrieved femoral head can elucidate the structural strength of the fractured femoral head and thereby can be used to predict migration of lag screws. Our result showed that directly measured BMD has a significant correlation with the HB migration on the osteoporotic femoral head. However, while the BMDs measured from the contralateral femoral neck or total hip is the most widely used parameter to predict the bone strength of the fractured femur, this may have limited usability to predict HB migration.

Phthalates and bone mineral density: a systematic review

BACKGROUND

Exposure to endocrine disruptors, such as phthalates, may impact bone mineral density (BMD) through a variety of mechanisms. Studies of phthalate exposure and BMD in humans are scarce.

OBJECTIVES

To synthesize published data on the association between phthalate metabolites and BMD in humans and to provide methodological suggestions for future research.

METHODS

A single investigator searched PubMed for relevant studies, including observational studies of phthalate exposure and BMD in children and postmenopausal women. Twelve studies were screened with 5 meeting the eligibility criteria and included for review. A quality assessment form was used as a quality measure and key information was extracted from the included studies.

RESULTS

In one prospective study among postmenopausal women, higher levels of monocarboxyoctyl phthalate (MCOP) and monocarboxynonyl phthalate (MCNP) were significantly associated with lower BMD among nonusers of hormone therapy (HT). In cross-sectional studies of postmenopausal women, monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono (3-carboxypropyl) phthalate (MCPP), and mono-benzyl phthalate (MBzP) were negatively associated with BMD, and MCNP was positively associated with BMD, but these results were not replicated across studies. In studies of fetal exposure to phthalates and childhood BMD, significant positive associations between MCPP and BMD in children at age 12 years were found in 1 study, while associations were null in the other study.

CONCLUSIONS

Studies among postmenopausal women provide suggestive evidence of an association between urinary phthalate metabolite concentration and decreased BMD. Results from studies of childhood BMD are inconclusive given the limited data and their limitations. More research is needed to address limitations and further investigate the association between phthalate exposure and human BMD.

Unravelling hip-spine bone mineral density discordance in people living with HIV

INTRODUCTION

In people living with HIV (PLWH), bone mineral density (BMD) discordance between the lumbar spine (LS) and femoral neck (FN) could be frequent given the high frequency of secondary osteoporosis, including HIV-related factors for bone disease.

MATERIALS AND METHODS

Retrospective cohort of PLWH with a dual X-ray absorptiometry scan. Hip-spine BMD discordance was defined as different T-score or Z-scores categories at LS and FN.

RESULTS

Overall, 865 individuals (mean 49.5 years, female 27%) were included. Osteoporosis diagnosis was four-to-seven times lower when both skeletal sites were affected than when considering the lowest T-score at any site (overall, 21% vs 4%). Hip-spine BMD discordance was observed in 381 (44%) individuals, it increased with age (from 43 to 52%, P = 0.032), and it was mainly due to lower LS-BMD. A lower FN-BMD was associated with older age, lower BMI (P < 0.01), and HIV-related factors, such as low CD4 + T-cell counts, duration of HIV infection, and time on antiretroviral therapy (ART). In a multivariate regression analysis, sex male (Odds Ratio, OR 4.901), hyperparathyroidism (OR, 2.364), and time on ART (OR 1.005 per month) were independently associated with discordance. A higher estimated fracture risk by FRAX equation was observed in individuals with BMD discordance due to lower FN-BMD compared to those with lower LS-BMD (+ 36% for major osteoporotic fracture, P = 0.04; + 135% for hip fracture, P < 0.01).

CONCLUSION

Hip-spine BMD discordance is highly prevalent in PLWH and it is associated with classical and HIV-related risk factors, modifying the rate of osteoporosis and fracture risk estimation.

Trabecular Bone Score as a Reliable Measure of Lumbar Spine Bone Microarchitecture in Acromegalic Patients

Although GH and IGF-1 excess has a controversial impact on bone mineral density (BMD), acromegalic patients display variable degrees of bone structure impairment. In this study, we aim to investigate the usefulness of trabecular bone score (TBS), compared to BMD, in identifying acromegalic patients with impaired lumbar spine trabecular microarchitecture. Forty-four acromegalic patients were investigated for disease control, metabolic and gonadal status, bone metabolism parameters, and the presence of vertebral fractures (VFs). Patients and matched healthy controls underwent BMD and TBS examination. Mean TBS values were lower in patients than in controls (p < 0.001), without significant differences in mean lumbar and femoral BMD. TBS values were significantly higher in controlled patients compared to the uncontrolled ones (p = 0.012). No significant differences were found in bone markers with respect to disease control. Mean TBS or lumbar BMD did not significantly differ in patients with or without VFs (prevalence 11.4%). TBS and BMD levels were lower in hypogonadal patients compared to the eugonadal ones (p = 0.030 and p < 0.001, respectively). In conclusion, TBS values are significantly lower in patients than in controls, confirming the presence of impaired lumbar spine trabecular bone in acromegaly. Both uncontrolled disease and hypogonadism contribute to TBS deterioration in acromegaly.

Vertebral Fractures Assessed by Dual-Energy X-Ray Absorptiometry and All-Cause Mortality: The Tromsø Study, 2007-2020

Vertebral fractures have been associated with increased mortality, but findings are inconclusive, and many vertebral fractures avoid clinical attention. We investigated this association in a general population of 2,476 older adults aged ≥55 years from Tromsø, Norway, who were followed over 2007-2020, using dual-energy x-ray absorptiometry (DXA) at baseline to evaluate vertebral fractures (mild, moderate, or severe). We used multiple Cox regression models to estimate hazard ratios (HRs) for all-cause mortality, adjusted for age, sex, body mass index, education, smoking, alcohol intake, cardiovascular disease, and respiratory disease. Mean follow-up in the cohort was 11.2 (standard deviation, 2.7) years; 341 participants (13.8%) had ≥1 vertebral fracture at baseline, and 636 participants (25.7%) died between baseline and follow-up. Full-adjustment models showed a nonsignificant association between vertebral fracture status (yes/no) and mortality. Participants with ≥3 vertebral fractures (HR = 2.43, 95% confidence interval: 1.57, 3.78) or ≥1 severe vertebral fracture (HR = 1.65, 95% confidence interval: 1.26, 2.15) had increased mortality compared with those with no vertebral fractures. Dual-energy x-ray absorptiometry-based screening could be a potent and feasible tool in detecting vertebral fractures that are often clinically silent yet independently associated with premature death. Our data indicated that detailed vertebral assessment could be warranted for a more accurate survival estimation.

Sarcopenia: Body Composition and Gait Analysis

Background

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

Objective

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

Materials and Methods

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

Results

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

Conclusion

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

Large-scale osteocyte lacunar morphological analysis of transiliac bone in normal and osteoporotic premenopausal women

Bone's ability to adapt is governed by the network of embedded osteocytes, which inhabit individual pores called lacunae. The morphology of these lacunae and their resident osteocytes are known to change with age and diseases such as postmenopausal osteoporosis. However, it is unclear whether alterations in lacunar morphology are present in younger populations with osteoporosis. To investigate this, we implemented a previously validated methodology to image and quantify the three-dimensional morphometries of lacunae on a large scale with ultra-high-resolution micro-computed tomography (microCT) in transiliac bone biopsies from three groups of premenopausal women: control n = 39; idiopathic osteoporosis (IOP) n = 45; idiopathic low BMD (ILBMD) n = 19. Lacunar morphometric parameters were measured in both trabecular and cortical bone such as lacunar density (Lc.N/BV), lacunar volume (Lc.V), and lacunar sphericity (Lc.Sr). These were then compared against each other and also with previously measured tissue morphometries such as bone volume density (BV/TV), trabecular separation (Tb.Sp), trabecular number (Tb.N), and others. We detected no differences in lacunar morphology between the IOP, ILBMD and healthy premenopausal women. In contrast, we did find significant differences between lacunar morphologies including Lc.N/BV, Lc. V, and Lc. Sr in cortical and trabecular regions within all three groups (p < 0.001), which was consistent with our previous findings on a subgroup of the healthy group. Furthermore, we discovered strong correlations between Lc. Sr from trabecular regions with the measured BV/TV (R = -0.90, p < 0.05). The findings and comprehensive lacunar dataset we present here will be a crucial foundation for future investigations of the relationship between osteocyte lacunar morphology and disease.

A Single Bout of Fatiguing Aerobic Exercise Induces Similar Pronounced Immunological Responses in Both Sexes

Introduction: Physical exercise can acutely and chronically modulate immunological responses. Women and men have different innate and adaptive immune responses, and in this sense, these two groups may also have different acute immunological responses induced by exercise. In addition, it is essential to understand further whether the effects of physical exercise on the immune system responses depend on sex because limited scientific evidence on this topic is available. This information may allow athletes and coaches to improve the training process, mainly to understand if the physiological impact of given training stimuli in women is similar to that in men.

Objective: The present study aimed to investigate the acute effects of continuous submaximal exercise until fatigue on physiological and immunological parameters in amateur female and male runners.

Methods: This study included 18 female and 15 male volunteers. Each participant visited the laboratory on four consecutive days. The first visit consisted of medical history taking and explaining the study design. On the second visit, the participants were subjected to an incremental test to determine their maximal rate of oxygen consumption (VO_2max) that was required to prescribe the intensity of the submaximal exercise protocol. On the third visit, the fatiguing exercise protocol was performed at 77%–80% of the VO_2max. During this submaximal exercise, the heart rate, rating of perceived exertion (RPE), and blood lactate were recorded. Blood samples were collected before, immediately after, and 1 h after the fatiguing protocol to analyze the plasma levels of cytokines and creatine kinase (CK) and to count leukocytes. Finally, on the fourth visit, the participants underwent physical evaluations to measure their body composition using dual-energy X-ray absorptiometry (DXA) imaging.

Results: The average ages of the female and male groups were 34.2 ± 3.7 and 30.5 ± 4.3 years old, respectively. The female group ran 57 ± 27 min, while the male group ran 52 ± 15 min before fatiguing. In the female group, when comparing before and after the submaximal exercise, marked increases were observed in the following variables: heart rate (from 68.5 to 180.4 bpm), RPE (from 3.6 to 8.2), lactate (from 2.1 to 4.49 mmol/L), and CK (from 89.5 to 126.3 U/L). In addition, the female group showed an increased number of total leukocytes (from 7222.3 to 11162.9 × 10⁶/μl), neutrophils (from 4,403 to 6,480 × 10⁶/μl), and lymphocytes (from 2,342 ± to 3,562 × 10⁶/μl) from pre- to post-submaximal exercise. In the male group, similar elevations in psychophysiological variables were observed, as evidenced by comparing the heart rate (from 52.8 to 184.1 bpm), RPE (from 0.0 to 8.9), lactate (from 2.7 to 7.2 mmol/L), and CK (from 106.2 to 165 U/L) before and after the submaximal exercise. The male group also showed an augmented number of total leukocytes (from 6,245 to 8,050 × 10⁶/μl), neutrophils (from 3,335 to 4,128 × 10⁶/), and lymphocytes (from 2,191 to 3,212 × 10⁶/μl) when comparing pre- and post-submaximal exercise. There were no differences in the changes between women and men for these parameters.

Conclusion: The aerobically fatiguing exercise protocol induced pronounced changes in the heart rate, plasma levels of lactate and CK, total leukocyte count, especially the number of neutrophils and lymphocytes, in both sexes. The fatiguing exercise protocol also changed the plasma levels of IL-6 and IL-10 in the female and male groups. Under the present conditions, the physiological changes induced by fatiguing submaximal exercise, including the immunological changes, were not influenced by sex. This study shows that the same aerobic physical exercise can alter immunological parameters in women and men, and this response is similar between sexes.

Evaluation of bone mineral density after instrumented lumbar fusion with computed tomography

BACKGROUND CONTEXT

Computed tomography (CT) measurement of Hounsfield Units (HU) has been described as a tool for assessing BMD. For surgeons considering a revision lumbar fusion, knowledge of the BMD of the UIV is of value for surgical planning. However, the presence of metal artifact from instrumentation presents a potential confounder, and prior studies have not validated measurements of HU in this setting.

PURPOSE

To determine if HU can be measured reliably at the supra-adjacent and upper instrumented levels of a lumbar fusion.

STUDY DESIGN

Retrospective observational cohort PATIENT SAMPLE: Consecutive series of patients who had lumbar CT scans after an instrumented posterior lumbar fusion.

OUTCOME MEASURES

Hounsfield Units at the upper instrumented vertebra and levels proximal.

METHODS

We analysed pre- and postoperative CT scans of 50 patients who underwent L2 and distal instrumented lumbar fusion whose scans were no greater than 1 year apart, obtaining HU measurements of analogous axial cuts at the upper instrumented level (immediately caudal to the halo of the pedicle screw), as well as additional control levels above the construct.

RESULTS

The HU at the pre-and postoperative UIV exhibited a strong correlation (r=0.917, p<.001), as did one (r=0.887, p<.001) and two (r=0.853, p<.001) levels above the UIV. There were significant but predictable reductions in the postoperative HU compared to preoperative at one (-9.0±26.2) and two (-12.2±30.2) levels above the UIV, as well as T12 (-13.9±42.2). There was no significant difference in HU at the UIV (4.6±34.1).

CONCLUSIONS

Postoperative HU at the UIV was strongly correlated with and not significantly different from the preoperative HU. Although the HU in the vertebrae proximal to the UIV were slightly lower postoperatively, this change was predictable using a correction factor.

Optical bone densitometry robust to variation of soft tissue using machine learning techniques: validation by Monte Carlo simulation

SIGNIFICANCE

To achieve early detection of osteoporosis, a simple bone densitometry method using optics was proposed. However, individual differences in soft tissue structure and optical properties can cause errors in quantitative bone densitometry. Therefore, developing optical bone densitometry that is robust to soft tissue variations is important for the early detection of osteoporosis.

AIM

The purpose of this study was to develop an optical bone densitometer that is insensitive to soft tissue, using Monte Carlo simulation and machine learning techniques, and to verify its feasibility.

APPROACH

We propose a method to measure spatially resolved diffuse light from three directions of the biological tissue model and used machine learning techniques to predict bone density from these data. The three directions are backward, forward, and lateral to the direction of ballistic light irradiation. The method was validated using Monte Carlo simulations using synthetic biological tissue models with 1211 different random structural and optical properties.

RESULTS

The results were computed after a 10-fold cross-validation. From the simulated optical data, the machine learning model predicted bone density with a coefficient of determination of 0.760.

CONCLUSIONS

The optical bone densitometry method proposed in this study was found to be robust against individual differences in soft tissue.

Finite element derived femoral strength is a better predictor of hip fracture risk than aBMD in the AGES Reykjavik study cohort

Hip fractures associated with a high economic burden, loss of independence, and a high rate of post-fracture mortality, are a major health concern for modern societies. Areal bone mineral density is the current clinical metric of choice when assessing an individual's future risk of fracture. However, this metric has been shown to lack sensitivity and specificity in the targeted selection of individuals for preventive interventions. Although femoral strength derived from computed tomography based finite element models has been proposed as an alternative based on its superior femoral strength prediction ex vivo, such predictions have only shown marginal or no improvement for assessing hip fracture risk. This study compares finite element derived femoral strength to aBMD as a metric for hip fracture risk assessment in subjects (N = 601) from the AGES Reykjavik Study cohort and analyses the dependence of femoral strength predictions and classification accuracy on the material model and femoral loading alignment. We found hip fracture classification based on finite element derived femoral strength to be significantly improved compared to aBMD. Finite element models with non-linear material models performed better at classifying hip fractures compared to finite element models with linear material models and loading alignments with low internal rotation and adduction, which do not correspond to weak femur alignments, were found to be most suitable for hip fracture classification.

The Global Burden of Osteoporosis, Low Bone Mass, and Its Related Fracture in 204 Countries and Territories, 1990-2019

BACKGROUND

Low bone mineral density (LBMD), including osteoporosis and low bone mass, has becoming a serious public health concern. We aimed to estimate the disease burden of LBMD and its related fractures in 204 countries and territories over the past 30 years.

METHODS

We collected detailed information and performed a secondary analysis for LBMD and its related fractures from the Global Burden of Disease Study 2019. Numbers and age-standardized rates related to LBMD of disability-adjusted life-years (DALYs) and deaths in 204 countries and territories were compared by age, gender, socio-demographic index (SDI), and location.

RESULTS

Global deaths and DALYs number attributable to LBMD increased from 207 367 and 8 588 936 in 1990 to 437 884 and 16 647 466 in 2019, with a raise of 111.16% and 93.82%, respectively. DALYs and deaths number of LBMD-related fractures increased 121.07% and 148.65% from 4 436 789 and 121248 in 1990 to 9 808 464 and 301 482 in 2019. In 2019, the five countries with the highest disease burden of DALYs number in LBMD-related fractures were India (2 510 288), China (1 839 375), United States of America (819 445), Japan (323 094), and Germany (297 944), accounting for 25.59%, 18.75%, 8.35%, 3.29%, and 3.04%. There was a quadratic correlation between socio-demographic index (SDI) and burden of LBMD-related fractures: DALYs rate was 179.985-420.435SDI+417.936SDI²(R^{2 =} 0.188, p<0.001); Deaths rate was 7.879-13.416SDI+8.839 SDI²(R^{2 =} 0.101, p<0.001).

CONCLUSIONS

The global burden of DALYs and deaths associated with LBMD and its related fractures has increased significantly since 1990. There were differences in disease burden between regions and countries. These estimations could be useful in priority setting, policy-making, and resource allocation in osteoporosis prevention and treatment.

The Effects of Body Position on Trochanteric Soft Tissue Thickness-Implications for Predictions of Impact Force and Hip Fracture Risk During Lateral Falls

Trochanteric soft tissue thickness (TSTT) is a protective factor against fall-related hip fractures. This study's objectives were to determine: (1) the influence of body posture on TSTT and (2) the downstream effects of TSTT on biomechanical model predictions of fall-related impact force (Ffemur) and hip fracture factor of risk. Ultrasound was used to measure TSTT in 45 community-dwelling older adults in standing, supine, and side-lying positions with hip rotation angles of -25°, 0°, and 25°. Supine TSTT (mean [SD] = 5.57 [2.8] cm) was 29% and 69% greater than in standing and side-lying positions, respectively. The Ffemur based on supine TSTT (3380 [2017] N) was 19% lower than the standing position (4173 [1764] N) and 31% lower than the side-lying position (4908 [1524] N). As factor of risk was directly influenced by Ffemur, the relative effects on fracture risk were similar. While less pronounced (<10%), the effects of hip rotation angle were consistent across TSTT, Ffemur, and factor of risk. Based on the sensitivity of impact models to TSTT, these results highlight the need for a standardized TSTT measurement approach. In addition, the consistent influence of hip rotation on TSTT (and downstream model predictions) support its importance as a factor that may influence fall-related hip fracture risk.

Operator-Related Errors and Pitfalls in Dual Energy X-Ray Absorptiometry: How to Recognize and Avoid Them

Dual-energy X-ray absorptiometry (DXA) is the most common modality for quantitative measurements of bone mineral density. Nevertheless, errors related to this exam are still very common, and may significantly impact on the final diagnosis and therapy. Operator-related errors may occur during each DXA step and can be related to wrong patient positioning, error in the acquisition process or in the scan analysis. The aim of this review is to provide a practical guide on how to recognize such errors in spine and hip DXA scan and how to avoid them, also presenting some of the most common artifacts encountered in clinical practice.

Is dual-energy absorptiometry accurate in the assessment of bone status of patients with chronic kidney disease?

Several patients with chronic kidney disease (CKD) have deteriorated bone status. Estimation of bone status using DXA has limitations especially in patients with CKD accompanying aortic calcifications. Quantitative CT and the trabecular bone score could be more accurate methods to estimate bone status for patients with CKD and vascular calcifications.

INTRODUCTION

It remains unclear whether dual-energy absorptiometry (DXA) is appropriate for the assessment of bone status in patients with chronic kidney disease (CKD), a disease that impacts bone health. The aims of this study were to compare DXA and central quantitative computed tomography (cQCT) and to evaluate bone status in patients with pre-dialysis CKD.

METHODS

This retrospective study included 363 healthy control subjects whose bone mineral density (BMD) was evaluated with DXA and 117 CKD patients whose BMD was evaluated using both cQCT and DXA. Diagnostic discordance was assessed between the lumbar spine (LS) and femur neck (FN) from DXA or between two modalities. The trabecular bone score (TBS) was extracted from DXA images. The volume of abdominal aortic calcification (AAC) was calculated using CT images from cQCT.

RESULTS

Using LS DXA T-score, osteoporosis was less common in the CKD group than in controls. Patients with normal LS BMD using DXA were reclassified into osteopenia or osteoporosis using cQCT in CKD patients. Among discordant subjects between FN and LS in DXA, a higher BMD of LS was more common in CKD patients than in controls. CKD patients had lower TBS than controls despite having the same diagnosis using DXA. AAC volume negatively correlated with BMD from cQCT and with TBS but not with BMD from DXA.

CONCLUSIONS

TBS and cQCT could accurately assess bone status in CKD patients since DXA may overestimate LS BMD, likely due to an increased AAC volume.

Osteoporosis is associated with varus deformity in postmenopausal women with knee osteoarthritis: a cross-sectional study

BACKGROUND

Varus deformity of the knee is a common pathological characteristic in knee osteoarthritis (KOA), and not enough attention has been given to the relationship between knee varus deformity and the state of systemic bone mass. The purpose of this study was to evaluate the potential relationship between bone mineral density (BMD) and varus deformity in postmenopausal women with KOA.

METHODS

A total of 202 postmenopausal women with KOA(KL grade ≥ 2)in our department from January 2018 to June 2020 were reviewed in this cross-sectional study. The hip-knee-ankle angle of the lower extremity (HKA), medial distal femoral angle (MDFA), medial proximal tibial angle (MPTA), and the angle of the joint line (JLCA) were measured in all patients. According to the HKA Angle, these participants were divided into the varus deformity group (HKA < 175.3°) and the normal limb alignment group (175.3°≤ HKA ≤ 180.3°). The BMD of the lumbar (L1-L4), left femoral neck, and left hip were measured by dual-energy X-ray absorptiometry in all patients. The difference in BMD between the knee varus deformity group and the normal limb alignment group was compared, and the relationship between the different angles of limb alignment and the BMD values at different sites was evaluated.

RESULTS

There were 144 cases (71.3 %) in the varus deformity group and 58 cases (28.7 %) in the normal limb alignment group. BMD at different joint sites within the knee varus deformity group was lower than of the normal limb alignment group, and the prevalence of osteoporosis was higher. After adjusting for confounding factors such as age, BMI, pain duration, and affected side, binary logistic regression showed that osteoporosis was an independent risk factor for varus deformity of KOA, and multiple linear regression showed that the BMD of spine, femoral neck, and hip was significantly associated with varus deformity of KOA. Pearson correlation analysis showed that BMD of the lumbar spine (L1-L4), left femoral neck and left hip joint were positively correlated with the HKA, but negatively correlated with JLCA. MPTA was positively correlated with the left femoral neck and left hip joint BMD, but not correlated with lumbar bone density. Furthermore, in the normal limb alignment group, the HKA was only negatively correlated with JLCA, but not significantly correlated with MDFA and MPTA. In the varus deformity group, the HKA was not only negatively correlated with JLCA but also positively correlated with MDFA and MPTA.

CONCLUSIONS

Osteoporosis should be a major risk factor for varus deformity in postmenopausal women with KOA. The progression of varus deformity of the knee should be concerned in postmenopausal women who simultaneously has KOA and osteoporosis.