Which central dual X-ray absorptiometry skeletal sites and regions of interest should be used to determine the diagnosis of osteoporosis?

The impact of bone mineral density on the risk of falling: evidence from genetic correlation and Mendelian randomization analysis

BACKGROUND

Falls are the most common consequence of low bone mineral density (BMD). However, due to limitations inherent in observational studies, the causal relationship between the two remains unestablished.

METHODS

This study utilized Mendelian Randomization (MR) analysis to explore the causal relationship between BMD and the risk of falling, incorporating linkage disequilibrium score (LDSC) regression for genetic correlation assessment. The primary method was inverse-variance weighted (IVW), supplemented with sensitivity analyses and the causal analysis using summary effect estimates (CAUSE) to address heterogeneity and pleiotropy biases.

RESULTS

LDSC analysis indicated significant genetic correlations between BMD at various sites and falling risk (rg range: -0.82 to 0.76, all P < 0.05). IVW analysis, with False Discovery Rate (FDR) correction, showed a protective causal effect of total body BMD (OR = 0.85, 95% CI 0.82-0.88, P = 7.63 × 10-17, PFDR = 1.91 × 10-16), femoral neck BMD (OR = 0.81, 95% CI 0.75-0.88, P = 3.33 × 10-7, PFDR = 5.55 × 10-7), lumbar spine BMD (OR = 0.85, 95% CI 0.79-0.91, P = 9.56 × 10-7, PFDR = 1.20 × 10-6), and heel BMD (OR = 0.82, 95% CI 0.79-0.81, P = 1.69 × 10-39, PFDR = 8.45 × 10-39) on falling risk. No causal relationship was found for forearm BMD (OR = 1.02, 95% CI 0.94-1.11, P = 0.64, PFDR = 0.64). Replication datasets and CAUSE analysis provided causal evidence consistent with the main findings.

CONCLUSION

The study established a causal relationship between BMD at four different sites and the risk of falling, highlighting potential areas for targeted prevention strategies.

Familial Resemblance of Bone Health in Maternal Lineage Pairs and Triads: A Scoping Review

INTRODUCTION

Female bone health is influenced by familial resemblance, health parameters and maturational periods (puberty and menopause); this combination has been researched using familial multi-generational cross-sectional studies.

AIM

This scoping review aimed to compile bone health research which uses sexually mature (grandmother-) mother-daughter pairs (and triads) and to determine the trends in its methodologies and familial comparisons.

METHODS

The Joanna Briggs Institute methodology for scoping reviews was used. Extraction included study and population characteristics, methodology (with an emphasis on imaging) and family-based results.

RESULTS

Twenty-nine studies were included, and their generations were categorized into four developmental categories: late adolescent to young adult, pre-menopause, mixed-menopause, and post-menopause. Eleven different pair/triad combinations were observed; the most common was pre-menopausal daughters and post-menopausal mothers. Dual-energy X-ray absorptiometry (DXA) was the most utilized imaging modality, and the hip was the most imaged region of interest (ROI). Regardless of pairing, imaging modality and ROI, there was often a trend toward significant familial resemblance and heritability (h2 and h2L).

CONCLUSION

This scoping review highlights the trends in bone health linked to familial resemblance, as well as the importance of menopause and late adolescence. This review compiles the commonalities and challenges within these studies to inform future research.

Bilateral hip DXA Reporting: 2023 Official Positions of the International Society for Clinical Densitometry

INTRODUCTION

This position development conference (PDC) Task Force examined the use and reporting of bilateral hip bone mineral density (BMD) measurements. This was deemed appropriate as increased availability of Dual-energy X-ray Absorptiometry (DXA) technology offering bilateral hip measurement resulted in more routine clinical use. The International Society for Clinical Densitometry Official Positions accept bilateral hip BMD measurement for clinical use but currently do not include recommendations for reporting those studies.

METHODS

Four key questions regarding bilateral hip reporting were proposed by the PDC Steering Committee. Relevant literature was identified using PubMed. Questions included whether bilateral hip measurements are appropriate for diagnostic classification or monitoring, as well as which bilateral hip regions of interest should be reported for diagnosis and monitoring. Additionally, the appropriate nomenclature for bilateral hip acquisition was defined.

RESULTS

The literature review demonstrated that bilateral hip measurement is appropriate and diagnostic classification should be based on the lowest T-score at the right or left side femoral neck or total hip; the mean T-score should not be used for diagnostic purposes. Mean bilateral total hip is preferred for BMD monitoring. The terms hip, or total hip were deemed appropriate nomenclature instead of femur or total proximal femur.

CONCLUSION

Bilateral hip acquisition is clinically appropriate and reporting and nomenclature standards are offered herein when a bilateral hip study is acquired. In terms of future research, the impact of discordant hips on diagnosis and monitoring was identified as a significant knowledge gap.

Hounsfield Unit for Evaluating Bone Mineral Density and Strength: Variations in Measurement Methods

OBJECTIVE

To assess the consistency and accuracy of various measurements of the Hounsfield unit (HU) in lumbar vertebrae.

METHODS

The study reviewed lumbar spine computed tomography images of 60 postmenopausal women aged >50 years. A total of 240 vertebrae were measured and analyzed for the variations of HU values in different sections and regions. Investigated the relationship between HU values of the lumbar spine under different measurements and dual-energy X-ray absorptiometry results and the ability to identify patients with osteoporosis.

RESULTS

HU values measured in midsagittal (r = 0.763), midcoronal (r = 0.768), and midaxial (r = 0.786) sections exhibited a strong positive correlation with dual-energy X-ray absorptiometry T-scores. HU values measured in midsagittal and midaxial sections of the vertebral body were in good agreement (P > 0.1), but decreased in the midcoronal (P < 0.001). HU values in the middle of the vertebral body were significantly higher than in the near end plate (P < 0.001). HU values varied between L1 and L4 vertebrae, but all had a good ability to identify osteoporosis and did not differ significantly in screening ability (P > 0.05).

CONCLUSIONS

An averaged HU value in axial multilevel is a comprehensive assessment of vertebral bone density. Using the HU value of the lumbar spine can help identify patients with osteoporosis, and the screening ability does not differ significantly across vertebral segments.

Hounsfield units on abdominal computed tomography: a new tool for predicting osteoporosis

BACKGROUND

Osteoporosis can cause bone fractures and disability, but early diagnosis faces challenges. Our proposed diagnostic indicators offer a new approach for early detection, which benefits early identification.

PURPOSE

To determine the most appropriate threshold for predicting osteoporosis in patients with each section of vertebral body.

MATERIAL AND METHODS

A retrospective analysis of 210 patients, including 646 vertebrae, who had both abdominal computed tomography (CT) and dual-energy X-ray absorptiometry (DXA) within six months. The correlation between DXA T-score and CT Hounsfield units (HU) values was tested by Pearson. The area under the curve (AUC) was calculated using the threshold obtained from the regression equation.

RESULTS

The thresholds matching the T-score of -2.5 were 85, 95, 85, and 90 HU for the upper axial plane of the vertebral body (Lau), the middle axial plane of the vertebral body (Lam), the lower axial plane of the vertebral body (Lad), and the mid-sagittal plane of the vertebral body (Lsm), respectively. Defining osteoporosis using CT as Lau ≤ 85, Lam ≤ 95, Lad ≤ 85, or Lsm ≤ 90 HU had a specificity of 88.1% (116/134) and sensitivity of 90.8% (69/76) for distinguishing DXA osteoporosis of the lumbar spine in 210 patients. T-score ≤-2.5 defined as Lau ≤85 or Lam ≤95 or Lad ≤85 or Lsm ≤90 HU had a specificity of 85.9% (275/320) and sensitivity of 82.8% (270/326) for DXA T-score ≤-2.5 in 646 lumbar vertebrae.

CONCLUSION

CT HU values obtained based on different sections of the vertebral body in abdominal CT can be used as a supplementary measure to assess osteoporosis.

Assessing Bone Mineral Density in Weight-Bearing Regions of the Body through Texture Analysis of Abdomen and Pelvis CT Hounsfield Unit

Objective: This study aimed to develop a novel method for opportunistically screening osteoporosis by measuring bone mineral density (BMD) from CT images. We addressed the limitations of commercially available software and introduced texture analysis using Hounsfield units (HU) as an alternative approach. Methods: A total of 458 samples (296 patients) were selected from a dataset of 1320 cases (782 patients) between 1 March 2013, and 30 August 2022. BMD measurements were obtained from the ilium, femoral neck, intertrochanteric region of both femurs, and L1-L5 and sacrum spine body. The region of interest (ROI) for each patient's CT scan was defined as the maximum trabecular area of the spine body, ilium, femoral neck, and femur intertrochanter. Using gray-level co-occurrence matrices, we extracted 45 texture features from each ROI. Linear regression analysis was employed to predict BMD, and the top five influential texture features were identified. Results: The linear regression (LR) model yielded correlation coefficients (R-squared values) for total lumbar BMD, total lumbar BMC, total femur BMD, total femur BMC, femur neck BMD, femur neck BMC, femur intertrochanter BMD, and femur intertrochanter BMC as follows: 0.643, 0.667, 0.63, 0.635, 0.631, 0.636, 0.68, and 0.68, respectively. Among the 45 texture features considered, the top five influential factors for BMD prediction were Entropy, autocorrelate_32, autocorrelate_32_volume, autocorrelate_64, and autocorrelate_64_volume.

Positions of The International Society for Clinical Densitometry and Their Etiology: A Scoping Review

The International Society for Clinical Densitometry convenes a Position Development Conference (PDC) every 2 to 3 years to make recommendations for guidelines and standards in the field of musculoskeletal measurement and assessment. The recommendations pertain to clinically relevant issues regarding the acquisition, quality control, interpretation, and reporting of measures of various aspects of musculoskeletal health. These PDCs have been meeting since 2002 and have generated 214 Adult, 26 FRAX, 41 pediatric, and 9 general nomenclature consideration positions, for a total of 290 positions. All positions are justified by detailed documents that present the background and rationale for each position. However, the linkage to these publications is not maintained by the ISCD or any other publication such that physicians cannot easily understand the etiology of the positions. Further, the wording of many positions has changed over the years after being reviewed by subsequent PDCs. This scoping review captures the references, changes, and timeline associated with each position through the 2019 PDC. It is meant to serve as a guide to clinicians and researchers for intelligent use and application of the positions.

First Ecuadorian statement consensus for the evaluation and treatment of osteoporosis

Osteoporosis management has become more relevant as the life expectancy increases. In Ecuador, approximately 19% of adults over 65 years of age have been diagnosed with osteoporosis. There is no national consensus for the management and prevention of the disease being this proposal the first Ecuadorian consensus.

INTRODUCTION

In Ecuador, it is estimated that around 19% of adults over 65 years of age have osteoporosis. Due to the increase in life expectancy in the world population, the evaluation and management of osteoporosis has become more relevant. Currently, there is no national consensus for the management and prevention of the disease. The Ecuadorian Society of Rheumatology presented the project for the elaboration of the first Ecuadorian consensus for the management and prevention of osteoporosis.

METHODS

A panel of experts in multiple areas and extensive experience was invited to participate. The consensus was carried out using the Delphi method. Six working dimensions were created: definition and epidemiology of osteoporosis, fracture risk prediction tools, non-pharmacological treatment, pharmacological treatment, calcium and vitamin D, and glucocorticoid-induced osteoporosis.

RESULTS

The first round was held in December 2021, followed by the second round in February 2022 and the third round in March 2022. The data was shared with the specialists at the end of each round. After three rounds of work, a consensus was reached for the management and prevention of osteoporosis.

CONCLUSION

This is the first Ecuadorian consensus for the management and treatment of postmenopausal osteoporosis.

Genome-wide polygenic risk score for major osteoporotic fractures in postmenopausal women using associated single nucleotide polymorphisms

BACKGROUND

Osteoporosis is highly polygenic and heritable, with heritability ranging from 50 to 80%; most inherited susceptibility is associated with the cumulative effect of many common genetic variants. However, existing genetic risk scores (GRS) only provide a few percent predictive power for osteoporotic fracture.

METHODS

We derived and validated a novel genome-wide polygenic score (GPS) comprised of 103,155 common genetic variants to quantify this susceptibility and tested this GPS prediction ability in an independent dataset (n = 15,776).

RESULTS

Among postmenopausal women, we found a fivefold gradient in the risk of major osteoporotic fracture (MOF) (p < 0.001) and a 15.25-fold increased risk of severe osteoporosis (p < 0.001) across the GPS deciles. Compared with the remainder of the GPS distribution, the top GPS decile was associated with a 3.59-, 2.48-, 1.92-, and 1.58-fold increased risk of any fracture, MOF, hip fracture, and spine fracture, respectively. The top GPS decile also identified nearly twofold more high-risk osteoporotic patients than the top decile of conventional GRS based on 1103 conditionally independent genome-wide significant SNPs. Although the relative risk of severe osteoporosis for postmenopausal women at around 50 is relatively similar, the cumulative incident at 20-year follow-up is significantly different between the top GPS decile (13.7%) and the bottom decile (< 1%). In the subgroup analysis, the GPS transferability in non-Hispanic White is better than in other racial/ethnic groups.

CONCLUSIONS

This new method to quantify inherited susceptibility to osteoporosis and osteoporotic fracture affords new opportunities for clinical prevention and risk assessment.

Evaluation of factors related to the occurrence of new fragility fractures: A case-control study

INTRODUCTION

Fragility fractures (FF) are frequent in osteoporotic patients. There are a series of risk factors and clinical variables that could predict their appearance.

MATERIAL AND METHOD

A retrospective observational study of cases and controls was carried out. Cases were defined by the presence of FF (326 participants) and controls by patients with similar characteristics without FF (629 participants).

RESULTS

Certain factors increase the risk of FF, such as a previous diagnosis of type 2 DM (OR: 2.001), 1ng/mL elevations of CTX (OR: 1.88), having a parental history of hip fracture (OR: 1.667), 5-year increase in age (OR: 1.39), and 1kg/m² increases in BMI (OR: 1.041). In contrast, other factors evaluated decreased this risk, such as maintaining 25(OH)D levels≥30ng/mL (OR: 0.686) and a T-score≥-2.5 (OR: 0.642).

CONCLUSIONS

Levels of 25(OH)D≥30ng/mL and a T-score at the femoral neck≥-2.5 are protective factors for FF, while a previous diagnosis of type 2 DM, an elevated CTX, a parental history of hip fracture, an increase of 1kg/m² in BMI and an increase in age by 5 years would be predisposing to FF.

[Translated article] Evaluation of factors related to the occurrence of new fragility fractures: A case-control study

INTRODUCTION

Fragility fractures (FF) are frequent in osteoporotic patients. There are a series of risk factors and clinical variables that could predict their appearance.

MATERIAL AND METHOD

A retrospective observational study of cases and controls was carried out. Cases were defined by the presence of FF (326 participants) and controls by patients with similar characteristics without FF (629 participants).

RESULTS

Certain factors increase the risk of FF, such as a previous diagnosis of type 2 DM (OR: 2.001), 1ng/mL elevations of CTX (OR: 1.88), having a parental history of hip fracture (OR: 1.667), 5-year increase in age (OR: 1.39), and 1kg/m² increases in BMI (OR: 1.041). In contrast, other factors evaluated decreased this risk, such as maintaining 25(OH)D levels≥30ng/mL (OR: 0.686) and a T-score≥-2.5 (OR: 0.642).

CONCLUSIONS

Levels of 25(OH)D≥30ng/mL and a T-score at the femoral neck≥-2.5 are protective factors for FF, while a previous diagnosis of type 2 DM, an elevated CTX, a parental history of hip fracture, an increase of 1kg/m² in BMI and an increase in age by 5 years would be predisposing to FF.

Global, regional prevalence, and risk factors of osteoporosis according to the World Health Organization diagnostic criteria: a systematic review and meta-analysis

This systematic review and meta-analysis estimated the global, regional prevalence, and risk factors of osteoporosis. Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from 8.0% in Oceania to 26.9% in Africa). Osteoporosis is a common metabolic bone disorder in the elderly, usually resulting in bone pain and an increased risk of fragility fracture, but few summarized studies have guided global strategies for the disease. Therefore, we pooled the epidemiologic data to estimate the global, regional prevalence, and potential risk factors of osteoporosis. We conducted a comprehensive literature search through PubMed, EMBASE, Web of Science, and Scopus, to identify population-based studies that reported the prevalence of osteoporosis based on the World Health Organization (WHO) criteria. Meta-regression and subgroup analyses were used to explore the sources of heterogeneity. The study was registered in the PROSPERO database (CRD42021285555). Of the 57,933 citations evaluated, 108 individual studies containing 343,704 subjects were included. The global prevalence of osteoporosis and osteopenia was 19.7% (95%CI, 18.0%-21.4%) and 40.4% (95%CI, 36.9%-43.8%). Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from Oceania 8.0% to 26.9% in Africa). The prevalence was higher in developing countries (22.1%, 95%CI, 20.1%-24.1%) than in developed countries (14.5%, 95%CI, 11.5%-17.7%). Our study indicates a considerable prevalence of osteoporosis among the general population based on WHO criteria, and the prevalence varies substantially between countries and regions. Future studies with robust evidence are required to explore risk factors to provide effective preventive strategies for the disease.

Effect of Discordant Hip Bone Density on Incident Fracture Risk: A Registry-Based Cohort Study

The Fracture Risk Assessment Tool (FRAX®) combines clinical risk factors and optionally femoral neck bone density to estimate major osteoporotic fracture (MOF) and hip fracture probability. Hip dual-energy X-ray absorptiometry (DXA) simultaneously measures the trochanter and total hip, but these regions are not considered by FRAX. Our aim was to determine whether discordance in trochanter and total hip bone density (defined as ≥1 T-score difference from the femoral neck) affects fracture risk adjusted for fracture probability. Using the Manitoba bone density registry, we identified 84,773 women and men age 40 years or older undergoing baseline hip DXA. The outcomes were incident MOF and hip fracture. Cox regression hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for baseline fracture probability were used to test the association between hip T-score discordance and incident fractures. Hip T-score discordance affected more than one in five subjects (trochanter lower in 3.9%, higher in 14.2%; total hip lower in 0.3%, higher in 14.9%). After mean 8.8 years there were 8444 incident MOF including 2664 hip fractures. Discordantly lower trochanter and lower total hip T-score (≥1 below femoral neck) was associated with increased risk for MOF (adjusted HRs 1.47 and 1.60) and hip fracture (HRs 1.85 and 2.12), while discordantly higher trochanter and total hip T-score (≥1 above femoral neck) was associated with lower risk for MOF (HRs 0.83 and 0.71) and hip fracture (HRs 0.79 and 0.68). In models that examined the trochanter and total hip simultaneously, discordantly lower trochanter T-score was associated with increased incident MOF and hip fracture risk (HRs 1.43 and 1.79) whereas discordantly higher total hip T-score was associated with lower risk (HRs 0.73 and 0.75). In conclusion, trochanter and total hip regions frequently show T-scores that are discordant with the femoral neck. This information strongly affects incident fracture risk independent of fracture probability scores computed with femoral neck bone density. © 2022 American Society for Bone and Mineral Research (ASBMR).

Hounsfield unit for assessing asymmetrical loss of vertebral bone mineral density and its correlation with curve severity in adolescent idiopathic scoliosis

Background

Low bone mass concomitantly occurs in patients with adolescent idiopathic scoliosis (AIS) and can persist until skeletal maturity. The purpose of this study was to assess the asymmetrical loss of vertebral bone mineral density (vBMD) and its correlation with curve severity in patients with AIS using Hounsfield unit (HU) values measured from computed tomography scans.

Methods

A total of 93 AIS patients were retrospectively recruited. The HU values of the vertebral body (VB-HU) and pedicle screw trajectory (PST-HU) were measured from four vertebrae above (Apex − 4) to four below (Apex + 4) the apical vertebra (Apex) of the major curve. The VB-HU and PST-HU at the upper end vertebra, Apex, and lower end vertebra within the concave and convex sides of the major and minor curves and stable vertebrae were obtained.

Results

A significant correlation was found between the Cobb angle and VB-HU at the periapical levels of the major curve. VB-HU and PST-HU at periapical levels were significantly greater within the concavity than the convexity of both major and minor curves. The asymmetric ratios of VB-HU and PST-HU were significantly correlated with the major curve Cobb angle, peaked at the apex, and gradually diminished from the apex to the end vertebrae. The asymmetrical loss of vBMD aggravated with the progression of curve severity, presenting as VB-HU, significantly decreased within the convexity and insignificantly decreased within the concavity of the major curve.

Conclusion

The asymmetrical loss of vBMD was associated with the progression of curve severity in AIS. For patients with severe AIS, the distraction of the pedicle screws at the concave side should be a priority in correcting the major curve, and supplemental anchors and larger-sized screws should be placed within the convex side around the apex of the major curve to reduce the risk of screw loosening after surgery.

Sarcopenic osteoporosis, sarcopenic obesity, and sarcopenic osteoporotic obesity in the Camargo cohort (Cantabria, Spain)

The associations of sarcopenia with osteoporosis or obesity have a very low prevalence. No trend towards an association between osteoporosis and sarcopenia is observed. Sarcopenia and obesity tend not to coincide, as if they were antagonistic disorders.

PURPOSE

To know (a) the prevalence in our region of sarcopenic osteoporosis (association of sarcopenia and osteoporosis (T-score < - 2.5)), sarcopenic obesity, and the association of osteoporosis, sarcopenia, and obesity; (b) the tendency of osteoporosis, sarcopenia, and obesity to associate with each other; and (c) the bone mineral density (BMD), the components of sarcopenia, and the prevalence of fragility fractures in these associations.

METHODS

The study was performed in the Camargo cohort. Osteoporosis was diagnosed by DXA, sarcopenia by the EWGSOP-1 criteria, and obesity by body mass index (BMI) and fat percentage. Fractures were verified radiographically or by consulting the medical records.

RESULTS

The prevalence of sarcopenic osteoporosis was 2.8% and the OR for this association 1.03 (p = 0.89). The prevalence of sarcopenic obesity by BMI was 1.4% and by fat percentage 5.9% (corresponding ORs: 0.18 (p < 0.0001) and 0.58 (p < 0.003) respectively). The prevalence of the association of osteoporosis, sarcopenia, and obesity was 0.0% when assessed by BMI and 0.8% when assessed by fat percentage. Patients with sarcopenic osteoporosis have less muscle mass and more fragility fractures than sarcopenic patients overall. In patients with sarcopenic obesity by fat percentage, muscle mass and strength, as well as physical performance, were similar to those of sarcopenic patients overall. Neither BMD nor fracture prevalence showed differences between patients with sarcopenic obesity and patients with sarcopenia or obesity in general.

CONCLUSION

Our study supports the idea that the prevalence of the mixed disorders studied is low. No significant association between osteoporosis and sarcopenia was found. Sarcopenia and obesity seem to tend to occur in different people, as if suffering from one of them hinders suffering from the other.

Reliability of Hounsfield Unit for Assessing Asymmetrical Vertebral Bone Mass in Adult Degenerative Scoliosis

Objective

Hounsfield Unit (HU) has been used to investigate the asymmetrical vertebral bone mass in patients associated with adult degenerative scoliosis (ADS). Therefore, there is an inevitable need to evaluate the performance of HU values in ADS subjects.

Methods

A total of 162 patients (81 ADS patients and 81 non-ADS patients) aged ≥50 years undergoing the CT examination were reviewed. The HU values of the lumbar vertebral body (including total, convex side, and concave side) at bilateral pedicle plane were obtained and compared. The paired t-test, chi-squared test, independent samples t-test, and interclass correlation coefficient (ICC) were used for statistical analyses.

Results

The HU values were significantly different between the convex and concave sides of the lumbar vertebral body (P < 0.01). The total prevalence of osteoporosis (OP) in ADS patients was higher than that of non-ADS patients. The prevalence of OP in female or male of ADS patients was higher than that of non-ADS patients, respectively. Intra- and inter-rater reliability were very strong (both >0.8) for measuring asymmetrical vertebral bone mass in ADS patients.

Conclusion

HU value was a high reproducibility method for evaluating the vertebral bone mass in ADS patients. The HU values at the concave sides were significantly higher than that of convex sides at the lumbar vertebral body on the pedicle plane. The prevalence of OP in ADS patients was higher than that of non-ADS patients, especially for females associated with ADS. Moreover, the static asymmetric load did not enhance the bone mass at the concave side compared with the left/right side of non-ADS patients.

The effect of pharmacological cessation and restoration of menstrual cycle on bone metabolism in premenopausal women with endometriosis

INTRODUCTION

GnRH-analogs induce bone loss. We aimed to investigate the effects of goserelin-induced menstrual cessation (MC) and subsequent menstrual restoration (MR) on bone metabolism (BM).

METHODS

In this prospective cohort study, premenopausal women (PMW) with histologically verified endometriosis (n = 21) received goserelin monthly for 6 months (6 m) resulting in MC and were followed up for another 6 m after MR (12 m). Age- and BMI-matched healthy PMW (n = 20) served as controls for bone mineral density (BMD) measurements. The primary endpoint was changes in lumbar spine (LS)-BMD at 6 m and 12 m; Secondary endpoints were changes in femoral neck (FN)-BMD, bone turnover markers (P1NP and CΤx), sclerostin, and expression of bone-related circulating microRNAs (miRNAs) at 6 m and 12 m.

RESULTS

Goserelin-induced MC reduced LS- and FN-BMD at 6 m (both p < 0.001). From 6 m to 12 m, LS-BMD increased (p < 0.001) but remained below baseline values (p = 0.012), whereas FN-BMD remained stable (p = 1.000). CTx and P1NP levels increased at 6 m (both p < 0.001) and decreased at 12 m (p < 0.001 and p = 0.013, respectively), while CTx (p = 1.000) alone and not P1NP (p = 0.020) returned to baseline. Sclerostin levels did not change. Relative expression of miRNAs targeting RUNX 2 and beta-catenin was significantly downregulated at 6 m compared to baseline (p < 0.001), while the expression of miRNAs targeting osteoblast and osteoclast function at both directions demonstrated a robust increase (up to 400fold) at 12 m (p < 0.001).

CONCLUSIONS

Six months of goserelin-induced MC lead to significant bone loss associated with increased bone turnover and changes in the expression of bone-related miRNAs, changes that are only partially reversed at 6 m after MR.

Blood Lead Level Is Negatively Associated With Bone Mineral Density in U.S. Children and Adolescents Aged 8-19 Years

CONTEXT

The relationship of lead (Pb) exposure with bone health in children and adolescents remains controversial.

OBJECTION

We aimed to investigate the association of blood lead levels (BLL) with bone mineral density (BMD) in American children and adolescents using data from the National Health and Nutrition Examination Survey (NHANES), 2005-2010.

METHODS

We analyzed 5,583 subjects aged 8-19 years (mean age, 13.49 ± 3.35 years) from the NHANES 2005-2010. BLL was tested using inductively coupled plasma mass spectrometry. BMD was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine, total femur, and femur neck. Multivariate linear regression models were used to explore the association between BLL and BMD, adjusting for age, gender, race/ethnicity, poverty income ratio (PIR), body mass index (BMI), serum calcium, and serum phosphorus.

RESULTS

BLL was negatively correlated with BMD at different sites of interest in children and adolescents. For every 1mg/dl increase in BLL, the BMD of the total spine, total hip, and femoral neck decreased by 0.011 g/cm², 0.008 g/cm², and 0.006 g/cm². In addition, Pb affected the lumbar spine more than the femur. The effect estimates were stronger in girls than boys at the lumbar spine (P for interaction= 0.006). This negative association remained significant in American children and adolescents after excluding individuals with BLL more than 3.5 ug/dl.

CONCLUSION

Our study indicates that BLL is negatively correlated with BMD at different sites of interest in children and adolescents aged 8-19 years, even in the reference range. More research is needed to elucidate the relationships between Pb and bone health in children and adolescents, including specific mechanisms and confounding factors like race/ethnicity, gender, and age.

Gut microbiota is associated with bone mineral density : an observational and genome-wide environmental interaction analysis in the UK Biobank cohort

AIMS

Despite the interest in the association of gut microbiota with bone health, limited population-based studies of gut microbiota and bone mineral density (BMD) have been made. Our aim is to explore the possible association between gut microbiota and BMD.

METHODS

A total of 3,321 independent loci of gut microbiota were used to calculate the individual polygenic risk score (PRS) for 114 gut microbiota-related traits. The individual genotype data were obtained from UK Biobank cohort. Linear regressions were then conducted to evaluate the possible association of gut microbiota with L1-L4 BMD (n = 4,070), total BMD (n = 4,056), and femur total BMD (n = 4,054), respectively. PLINK 2.0 was used to detect the single-nucleotide polymorphism (SNP) × gut microbiota interaction effect on the risks of L1-L4 BMD, total BMD, and femur total BMD, respectively.

RESULTS

We detected five, three, and seven candidate gut microbiota-related traits for L1-L4 BMD, total BMD, and femur BMD, respectively, such as genus Dialister (p = 0.004) for L1-L4 BMD, and genus Eisenbergiella (p = 0.046) for total BMD. We also detected two common gut microbiota-related traits shared by L1-L4 BMD, total BMD, and femur total BMD, including genus Escherichia Shigella and genus Lactococcus. Interaction analysis of BMD detected several genes that interacted with gut microbiota, such as phospholipase D1 (PLD1) and endomucin (EMCN) interacting with genus Dialister in total BMD, and COL12A1 and Discs Large MAGUK Scaffold Protein 2 (DLG2) interacting with genus Lactococcus in femur BMD.

CONCLUSION

Our results suggest associations between gut microbiota and BMD, which will be helpful to further explore the regulation mechanism and intervention gut microbiota of BMD. Cite this article: Bone Joint Res 2021;10(11):734-741.

Could Computed Tomography Hounsfield Unit Values of Lumbar Vertebrae Detect Osteoporosis?

BACKGROUND

Dual-energy X-ray absorptiometry (DEXA) scanning has several disadvantages determining osteoporosis, especially for the degenerative spine.

INTRODUCTION

This study aims to determine spinal osteoporosis in patients suffering from lumbar degenerative disease using computed tomography (CT).

METHODS

A total of 547 subjects that underwent DEXA and abdominal CT within a period of three months were examined retrospectively and separated into groups based on lumbar degenerative alteration on the CT scan. The subjects that showed degenerative severity at L1-L4, in at least two levels, were graded and placed in the degenerative group (Group D, n=350). In contrast, the other subjects constituted the control group (Group C, n=197). The Hounsfield unit (HU) of the vertebral body trabecular bone, the T-score, and bone mineral density (BMD) of L1-L4 and hips were determined from the CT images. CT-HU parameters for osteoporosis acquired from the control group were used to ascertain undiagnosed osteoporosis.

RESULTS

The CT-HU was positively correlated with T-score and lumbar BMD for both groups (P<0.001), while the L1-L4 correlation was higher in Group C than in Group D. Based on linear regression, the T-score and CT-HU for L1-L4 osteoporosis were 129, 136, 129 and 120 HU, respectively in Group C. Undiagnosed spinal osteoporosis was greater in Group D compared to the controls (44.2% vs. 9.6%, respectively) based on the CT-HU thresholds.

CONCLUSION

Lumbar spine degeneration can augment BMD and T-score, resulting in the underestimation of lumbar osteoporosis. The osteoporosis threshold determined by CT-HU may be a valuable technique to determine undiagnosed spinal osteoporosis.

High prevalence of osteoporosis in patients undergoing spine surgery in China

Background

With the increase in life expectancy, a large number of patients with osteoporosis (OP) are undergoing spine surgery, which may adversely affect the surgical success rate. The prevalence of OP varies in different regions, and no data are available that represent the prevalence of OP among Chinese patients over 50 years of age who are undergoing spine surgery. It was the first multicenter study to assess OP in these patients. Aiming to obtain comprehensive data, this study combined bone mineral density (BMD) measurements and visual radiography assessment (VRA) to analyze the prevalence of OP in patients aged > 50 years who underwent spine surgery.

Methods

Data from 1,856 patients aged over 50 years undergoing spine surgery who resided in northern, central, and southern China were reviewed between 2018 and 2019. Based on the perioperative BMD and X-ray data, we calculated the prevalence of OP in this special population according to sex, age, and spine degenerative disease.

Results

A total of 1,245 patients (678 females and 567 males) were included in the study. The prevalence of OP diagnosed by BMD was 52.8 % in females and 18.7 % in males. When we combined with BMD and VRA, the prevalence of OP increased from 52.8 to 65.9 % in females and from 18.7 to 40.6 % in males. Although OP was more severe in females than in males, a significant difference in the rate of vertebral fracture (VF) was not observed between females and males with a normal BMD and osteopenia (females vs. males: aged 50–59 years, P = 0.977; 60–69 years, P = 0.302; >70 years, P = 0.172). Similarly, no significant difference in the vertebral fracture rate was observed within different age groups of patients with a normal BMD and osteopenia (females: P = 0.210; males, P = 0.895). The incidence of OP in patients with degenerative scoliosis was higher than that in the remaining patients (females: 63.6 % vs. 42.4 %, P = 0.018; males: 38.9 % vs. 13.8 %, P = 0.004).

Conclusions

A high prevalence of OP was identified in patients aged > 50 years undergoing spine surgery, especially in patients whose primary diagnosis was degenerative scoliosis. BMD and VRA evaluations should be included in the clinical routine for these patients prior to surgery.

A pilot study comparing daily teriparatide with monthly cycles of teriparatide and raloxifene

This 6-month pilot study in osteoporotic postmenopausal women evaluated cyclic TPD/RLX compared to daily subcutaneous TPD with the concept of optimizing bone formation. Compared to daily subcutaneous TPD, cyclic therapy showed comparable increase in spine BMD and favorable effects on total proximal femur BMD and cortical thickness.

PURPOSE

There is no cure for osteoporosis; better medications or different approaches with current agents are needed. We hypothesized that monthly cycles of teriparatide (TPD) followed by raloxifene (RLX) might promote ongoing bone formation. Additionally, as TPD might initially adversely affect hip BMD, such effects may be mitigated by a cyclic approach. Therefore, this 6-month pilot study evaluated the effect of cyclic TPD/RLX compared to daily subcutaneous TPD on bone markers, BMD, trabecular bone score (TBS), and hip parameters assessed by 3D modeling.

METHODS

Postmenopausal osteoporotic women (n=26) were randomized to open-label TPD 20 daily or alternating monthly cycles of TPD followed by monthly RLX 60 mg daily. BMD was measured at the lumbar spine (LS), femur, and radius by DXA. To further assess LS BMD, QCT and opportunistic CT (L1 Hounsfield units [HU]) were performed. LS TBS and hip cortical and trabecular parameters were assessed using DXA. Baseline group comparisons were performed by unpaired T-test with change over time evaluated by repeated measures ANOVA.

RESULTS

Participant mean age, BMI, and lowest T-score were 67.0 years, 26.0 kg/m², and -2.7; no between-group differences in serum chemistries, 25(OH)D, or BMD were observed. LS-BMD increased (p<0.001) with TPD or TPD/RLX as measured by DXA (4.8%/5.2%), QCT (13%/9.4%), or HU (15.6%/10.2%) with no between-group difference. TPD/RLX produced beneficial between-group differences in total proximal femur BMD (1.5%, p<0.05) and cortical thickness (1.6%, p<0.05).

CONCLUSION

Compared with daily TPD, cyclic TPD/RLX comparably increased spine BMD and might have favorable effects on proximal femur BMD and cortical thickness.

Use of Hounsfield units of S1 body to diagnose osteoporosis in patients with lumbar degenerative diseases

OBJECTIVEThe aim of this study was to evaluate the use of Hounsfield unit (HU) values of the S1 body to diagnose osteoporosis in patients with lumbar degenerative diseases.METHODSThe records of 316 patients of ages ≥ 50 years and requiring surgery for lumbar degenerative diseases were reviewed. The bone mineral density (BMD) of the S1 body and L1 was measured in HU with preoperative lumbar CT. Circular regions of interest (ROIs) were placed on midaxial and midsagittal images of the S1 body. Dual-energy x-ray absorptiometry (DXA) and the criterion of L1 HU ≤ 110 HU were used to diagnose osteoporosis. The area under the receiver operating characteristic curve (AUC) was calculated to assess the use of HUs of the S1 body to diagnose osteoporosis.RESULTSThe interobserver and intraobserver reliability of measuring HU of the S1 body was excellent with intraclass correlation coefficients over 0.8 (p < 0.001). The correlation between HUs of the S1 body and average T-score of L1-4 was significant with Pearson correlation coefficients ≥ 0.60 (p < 0.001). The AUCs for using HUs of the S1 body to diagnose osteoporosis were 0.86 and 0.88 for axial HU and sagittal HU, respectively (p < 0.001). The HU thresholds with balanced sensitivity and specificity for diagnosing osteoporosis were 202 HU for axial HU (sensitivity: 76%; specificity: 76%) and 185 HU for sagittal HU (sensitivity: 80%; specificity: 80%).CONCLUSIONSBoth sagittal and axial HUs of the S1 body are useful tools for assessing BMD and diagnosing osteoporosis. Measuring HUs of the S1 body preoperatively from lumbar CT may help with surgical planning for patients with lumbar degenerative diseases.

Computed tomography Hounsfield unit-based prediction of pedicle screw loosening after surgery for degenerative lumbar spine disease

OBJECTIVE

The authors investigated the relation between Hounsfield unit (HU) values measured on CT and the risk of pedicle screw loosening in patients who underwent lumbar pedicle screw fixation for degenerative lumbar spine disease.

METHODS

Patients who were treated with lumbar pedicle screw fixation between July 2011 and December 2015 at the authors' department were reviewed. Age, sex, BMI, smoking and diabetes histories, range of fixation, and fusion method were recorded as the basic patient information. The HU values for lumbar bone mineral density (BMD) for the L1, L2, L3, and L4 vertebra were measured on CT scans. Logistic regression analysis was used to identify the independent influencing factors of pedicle screw loosening.

RESULTS

A total of 503 patients were included in the final analysis. The pedicle screw loosening rate at the 12-month follow-up was 30.0% (151 of 503 patients). There were no significant differences in sex, BMI, or histories of smoking and diabetes between the patients with (loosening group) and those without (nonloosening group) screw loosening (p > 0.05). The mean HU value of L1-4 was lower in the loosening group than the nonloosening group (106.3 ± 33.9 vs 132.6 ± 42.9, p < 0.001). In logistic regression analysis, being male (OR 2.065; 95% CI 1.242-3.433), HU value (OR 0.977; 95% CI 0.970-0.985), length of fixation (OR 3.616; 95% CI 2.617-4.996), and fixation to S1 (OR 1.699; 95% CI 1.039-2.777) were the independent influencing factors for screw loosening.

CONCLUSIONS

HU value measured on CT was an independent predictor for pedicle screw loosening, and lower HU value was significantly correlated with higher risk of screw loosening.

Prevalence of Osteoporosis in Patients Undergoing Lumbar Fusion for Lumbar Degenerative Diseases: A Combination of DXA and Hounsfield Units

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To investigate the prevalence of osteoporosis (OP) in patients undergoing lumbar fusion for lumbar degenerative diseases (LDD).

SUMMARY OF BACKGROUND DATA

OP is related to many complications after lumbar fusion for patients with LDD. There are sparse data on the prevalence of OP among this specific population. Moreover, LDD can falsely elevate the bone mineral density measured by dual energy x-ray absorptiometry (DXA), leading to unreliable diagnostic results. Computed tomography (CT) Hounsfield unit (HU) values can help identify osteoporotic patients undetected by DXA.

METHODS

A total of 479 patients aged≥50 years undergoing lumbar fusion for LDD were reviewed. The diagnosis of OP using DXA was based on World Health Organization criterion. The criterion for OP diagnosed on CT scan was the L1-HU value≤110.

RESULTS

The prevalence of OP diagnosed on lumbar DXA, hip DXA, and both was 32.4%, 19.6%, 39.7%, respectively. The females had higher prevalence of OP diagnosed on DXA (spine and hip) than males (48.9% vs. 27.1%, P < 0.001). In females but not males, the prevalence of OP significantly increased with age (females, 50-59: 28.0%, 60-69: 58.1%, ≥70: 78.8%, P < 0.001). Patients having primary diagnosis of degenerative lumbar scoliosis had the higher prevalence of OP than the rest patients (56.5% vs. 36.8%, P = 0.002). Among the 324 patients diagnosed with non-OP by lumbar DXA, the prevalence of OP diagnosed on CT scan was 25.9%, it increased with age and was also highest in patients with degenerative lumbar scoliosis.

CONCLUSION

OP was quite common among patients aged≥50 years undergoing lumbar fusion for LDD, especially for females aged≥60 years or patients having degenerative lumbar scoliosis. Older patients or patients having degenerative lumbar scoliosis are more likely to have unreliable lumbar T-scores. Measurements of HU values can help identify more osteoporotic patients in this population.

LEVEL OF EVIDENCE

3.

Hounsfield units value is a better predictor of pedicle screw loosening than the T-score of DXA in patients with lumbar degenerative diseases

PURPOSE

To compare the performance of using Hounsfield units (HU) value derived from computed tomography and T-score of dual-energy X-ray absorptiometry (DXA) to predict pedicle screw loosening.

METHODS

We reviewed 253 patients aged ≥ 50 years undergoing pedicle screw fixation for lumbar degenerative diseases (LDD). The evaluation of screw loosening: radiolucent zones of ≥ 1 mm thick in X-ray. The criterion for osteoporosis: the lowest T-score ≤ - 2.5. The average HU value of L1-L4 was used to represent lumbar bone mineral density (BMD). The area under receiver operating characteristics curve (AUC) was used to evaluate the performance of predicting screw loosening.

RESULTS

One patient underwent reoperation for screw loosening at 9 months follow-up. At 12 months follow-up, the loosening rate was 30.6% (77/252) in the remaining 252 patients. Osteoporotic patients had higher loosening rate than non-osteoporotic patients (39.3% vs. 25.8%, P = 0.026). The T-score showed no significant difference between loosening group and non-loosening group (- 2.1 ± 1.5 vs. - 1.7 ± 1.6, P = 0.074), and so is the lowest lumbar BMD of DXA (0.83 ± 0.16 g/cm² vs. 0.88 ± 0.19 g/cm², P = 0.054). The HU value was lower in the loosening group (106.8 ± 34.4 vs. 129.8 ± 45.7, P < 0.001). The HU value (OR, 0.980; 95%CI 0.968-0.993; P = 0.002) was the independent influencing factor of screw loosening. The AUC of predicting screw loosening was 0.666 (P < 0.001) for HU value and 0.574 (P = 0.062) for T-score.

CONCLUSIONS

HU value is a better predictor of pedicle screw loosening than T-score of DXA in patients aged ≥ 50 years with LDD. We should not only focus on the DXA measurements when making surgical plans concerning lumbar fixation. These slides can be retrieved under Electronic Supplementary Material.

T-score differences and nonprogression in lumbar vertebrae as predictors of vertebral fractures

PURPOSE

In case of a vertebral fracture, the area of the vertebrae decreases with a concomitant increase in BMD, as assessed by a DXA scanning. Furthermore, a vertebral fracture may disrupt the normal increase in vertebral body area from L1 to L4 (nonprogression). We aimed to examine associations between T-score difference and nonprogression of vertebral area and vertebral fractures.

METHODS

We identified 100 patients with 1 or more fractures in L1-L4 and 106 patients without fractures. All patients had undergone a DXA scan and a lumbar spine X-ray. In fracture patients, we recorded T-score difference between the fractured vertebra and the adjacent vertebra, and whether the fractured vertebra was smaller than the one above (nonprogression). In nonfracture patients, the greatest positive T-score difference was recorded, and nonprogression was present if vertebral area did not increase successively from L1 to L4.

RESULTS

With a T-score difference ≥1 SD odds ratio for fracture was 1.30 (0.74-2.29). Sensitivity and specificity were 0.40 and 0.66, respectively. With T-score difference ≥1.5 SD, odds ratio for fracture was 2.26 (1.08-4.73). Sensitivity and specificity were 0.24 and 0.88, respectively. Nonprogression was very common in the no-fracture group (38%), while only 23% of X-ray verified fractures had nonprogression.

CONCLUSION

A randomly found T-score difference ≥1.5 SD between adjacent vertebrae on a DXA scan is associated with a small increased risk of compression fracture. Nonprogression is very common in patients without fractures.

CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE QUALITY OF DXA SCANS AND REPORTS

OBJECTIVE

High-quality dual-energy X-ray absorptiometry (DXA) scans are necessary for accurate diagnosis of osteoporosis and monitoring of therapy; however, DXA scan reports may contain errors that cause confusion about diagnosis and treatment. This American Association of Clinical Endocrinologists/American College of Endocrinology consensus statement was generated to draw attention to many common technical problems affecting DXA report conclusions and provide guidance on how to address them to ensure that patients receive appropriate osteoporosis care.

METHODS

The DXA Writing Committee developed a consensus based on discussion and evaluation of available literature related to osteoporosis and osteodensitometry.

RESULTS

Technical errors may include errors in scan acquisition and/or analysis, leading to incorrect diagnosis and reporting of change over time. Although the International Society for Clinical Densitometry advocates training for technologists and medical interpreters to help eliminate these problems, many lack skill in this technology. Suspicion that reports are wrong arises when clinical history is not compatible with scan interpretation (e.g., dramatic increase/decrease in a short period of time; declines in previously stable bone density after years of treatment), when different scanners are used, or when inconsistent anatomic sites are used for monitoring the response to therapy. Understanding the concept of least significant change will minimize erroneous conclusions about changes in bone density.

CONCLUSION

Clinicians must develop the skills to differentiate technical problems, which confound reports, from real biological changes. We recommend that clinicians review actual scan images and data, instead of relying solely on the impression of the report, to pinpoint errors and accurately interpret DXA scan images.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; BMC = bone mineral content; BMD = bone mineral density; DXA = dual-energy X-ray absorptiometry; ISCD = International Society for Clinical Densitometry; LSC = least significant change; TBS = trabecular bone score; WHO = World Health Organization.

Lumbar spine bone mineral density Z-score discrepancies by dual X-ray absorptiometry do not predict vertebral fractures in children

Dual X-ray absorptiometry (DXA) remains the most common mode of bone mineral density (BMD) evaluation. In adults, presence of a lumbar spine (LS) BMD T-score discrepancy (>1 SD difference between adjacent vertebrae) can indicate a vertebral fracture. In children, however, the clinical significance of such discrepancies is unknown. We conducted a retrospective study to evaluate the association between LS DXA and LS morphology to elucidate the clinical significance of an LS BMD Z-score discrepancy. We identified 360 DXA scans performed between September 2014 and May 2016 in patients 5-18 years of age. DXA scans were cross-referenced against available LS radiographs and vertebral fracture assessment (VFA) within the 6 months preceding or following a DXA scan. After excluding 44 DXA scans because of spinal hardware, incomplete DXA, or repeat scans, 316 DXA scans were included; 81 (25.6%) had either an LS radiograph or a VFA. Twenty-five of 81 patients (30.9%) had >1 SD difference between adjacent vertebrae in LS BMD Z-score. Two of these 25 patients (8%) had a lumbar vertebral fracture documented by a spine radiograph. Of the remaining 56 patients who did not have a discrepancy >1 SD, 6 patients (11%) had a lumbar vertebral fracture. Discrepancies in LS BMD Z-scores were not associated with lumbar vertebral fractures and, in the absence of fractures, likely represented vertebral developmental variants in children whose skeletons are still growing. Therefore, it does not appear justified to recommend further imaging based solely on the results of a DXA scan without clinically meaningful indications.

Quantitative computed tomographic evaluation of bone mineral density in beagle dogs: comparison with dual-energy x-ray absorptiometry as a gold standard

This study aimed to demonstrate the higher accuracy and reproducibility of quantitative computed tomography (QCT) compared with dual-energy X-ray absorptiometry (DXA) as a gold standard for measuring canine bone mineral density (BMD). Seven middle-aged beagle dogs underwent lumbar vertebral and bilateral femoral DXA and QCT scans. BMD (mg/cm²) was measured at the vertebral body from L2 to L6, femoral neck, and proximal and distal femoral diaphyses. The BMD values were measured 3 times and compared. The BMD value on QCT was higher than that on DXA for femoral BMD but not for vertebral BMD. The correlation was strong for the lumbar vertebrae (r=0.66) and was strongest for L3 (r=0.85). No correlation was found for the femoral neck (P=0.35), and only moderate correlations were found for the proximal and distal femoral diaphyses (r=0.43 and r=0.40, respectively). The limits of agreement were narrower for vertebral BMD than for femoral BMD, and L3 had the narrowest limits of agreement. The intraclass correlation (ICC) was higher for DXA than for QCT at all lumbar and femoral sites measured, but the ICC of QCT was higher than 0.7. In conclusion, L3 can be used to monitor changes in BMD, and relative values and sequential monitoring of femoral BMD can also be useful because of the high reproducibility of QCT measurements. QCT would be a useful technique for evaluation of BMD in veterinary practice.

Diagnostic imaging of osteoporosis and sarcopenia: a narrative review

Osteoporosis and sarcopenia represent two major health problems with an increasing prevalence in the elderly population. The correlation between these diseases has been widely reported, leading to the development of the term "osteosarcopenia" to diagnose those patients suffering from both diseases. Several imaging methods for the diagnosis and management of osteoporosis exist, with dual-energy X-ray absorptiometry (DXA) being the most commonly used for measuring bone mineral density (BMD). Imaging technique other than DXA is represented by conventional radiography, computed tomography (CT) and ultrasound (US). Similarly, the imaging technologies used to detect loss of skeletal muscle mass in sarcopenia include DXA, CT, US and magnetic resonance imaging (MRI). These methods differ in terms of reliability, radiation exposure and costs. CT and MRI represent the gold standard for evaluating body composition (BC), but are costly and time-consuming. DXA remains the most often used technology for studying BC, being quick, widely available and with low radiation exposure.

Vertebral Body Compressive Strength Evaluated by Dual-Energy X-Ray Absorptiometry and Hounsfield Units In Vitro

Dual-energy X-ray absorptiometry (DXA) and Hounsfield unit (HU) are 2 technologies used in vivo to assess bone mineral density and to predict fracture risk. However, few in vitro studies focus on the difference between the 2 technologies in the ability to determine vertebral body compressive strength. Forty-two lumbar vertebrates were harvested from 7 mature goats. All the vertebrae were imaged using clinical computed tomography and assessed by DXA subsequently. The individual vertebral body was then mechanically tested to failure in compression, to determine ultimate load and stress. HU has a moderate correlation with DXA (r = 0.64). DXA has significant associations with ultimate load and stress (r = 0.59 and 0.69, respectively). Significant positive linear correlations were also found between HU and ultimate load (r = 0.65) and stress (r = 0.81). There was no significant difference between HU and DXA to predict the ultimate load (t = 0.56, p = 0.577) or the ultimate stress (t = 1.62, p = 0.112). HU has an equal predictive value as the DXA for whole vertebral body compressive strength. This work supports the application of the HU measurement using clinical computed tomography imaging technology to assess bone strength and fracture risk.

Cortical Bone Thickness of the Distal Part of the Tibia Predicts Bone Mineral Density

BACKGROUND

Poor bone density may affect surgical planning, treatment outcome, and postoperative protocols. Many patients with foot and ankle problems have not undergone a dual x-ray absorptiometry (DXA) scan, which is currently the gold standard for determining bone density. The purpose of this study was to determine if the cortical bone thickness (CBT) of the distal part of the tibia measured on radiographs correlated with bone mineral density.

METHODS

After exclusion criteria were applied, 167 consecutive adult patients (mean age and standard deviation [SD], 62 ± 11.62 years) who had had standardized ankle radiographs and a DXA scan within 6 months of each other were included in this retrospective study. The CBT was measured with both the gauge and the average method on standardized anteroposterior, lateral, and hindfoot alignment radiographs. The relationship between CBT in the distal part of the tibia and DXA findings in the hip, proximal part of the femur, and lumbar spine was assessed with Pearson correlations. The interrater and intrarater reliability of CBT measurements was assessed with intraclass correlation coefficients. Subgroup analysis was performed to determine the ability of CBT thresholds to predict osteoporosis.

RESULTS

Average CBT measurements on the anteroposterior, lateral, and hindfoot alignment views strongly correlated with DXA findings in the proximal part of the femur (r = 0.70, 0.64, and 0.55, respectively; p < 0.0001), the hip (r = 0.74, 0.67, and 0.53; p < 0.0001), and the lumbar spine (r = 0.61, 0.60, and 0.47; p < 0.0001). The interrater and intrarater reliability of the CBT measurements was excellent. Use of a 3.5-mm average CBT of the distal part of the tibia on the anteroposterior view as the threshold value for predicting osteoporosis (T score less than -2.5) had a sensitivity of 100%, a specificity of 25%, an accuracy of 33%, a positive predictive value of 19%, and a negative predictive value of 100%.

CONCLUSIONS

Measurement of the average CBT of the distal part of the tibia is a quick and reliable method for obtaining information on bone quality. CBT measured on standard ankle radiographs correlated strongly with DXA results and may prove to be a useful screening tool for osteoporosis.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Biochemical Predictors of Low Bone Mineral Density and Fracture Susceptibility in Maltese Postmenopausal Women

Osteoporosis and fractures are complex conditions influenced by an interplay of genetic and environmental factors. The aim of the study was to investigate three biochemical parameters including total serum calcium, total serum alkaline phosphatase (sALP) and albumin in relation to bone mineral density (BMD) at the lumbar spine and femoral neck (FN), and with all-type of low-trauma fractures in Maltese postmenopausal women. Levels were also correlated with age and physical activity. A case-control study of 1045 women was performed. Women who suffered a fracture were classified as cases whereas women without a fracture history were included as controls subdivided into normal, osteopenic, or osteoporotic according to their BMD measurements. Blood specimens were collected following good standard practice and testing was performed by spectrophotometry. Calcium and sALP levels were weakly correlated with FN BMD levels (calcium: r = -0.111, p = 0.002; sALP: r = 0.089, p = 0.013). Fracture cases had the lowest serum levels of calcium, sALP and albumin relative to all other control groups, which decreased with increasing age, possibly increasing fracture risk. Biochemical levels were lowest in women who sustained a hip fracture and more than one fracture. Biochemical parameters decreased with reduced physical activity; however, this was most evident for fracture cases. Reduced physical activity was associated with lower BMD levels at the hip, and to a lower extent at the spine. In conclusion, results suggest that levels of serum calcium and albumin could be indicative of fracture risk, whereas calcium levels and to lower extent sALP levels could be indicators of hip BMD.

The distribution of bone mass in the lumbar vertebrae: are we measuring the right target?

BACKGROUND CONTEXT

The ideal target of bone mineral density (BMD) measurements of the spine is the trabecula-rich vertebral body. Yet, spine BMD measurements routinely obtained with dual-energy X-ray absorptiometry also include the posterior elements of the vertebra, which are mainly cortical bone and insensitive to bone loss.

PURPOSE

We compared the bone mass of the vertebral body and posterior elements to determine the contributions of vertebral components to vertebral BMD measurements.

STUDY DESIGN

A micro-computed tomography study of lumbar vertebral bone.

METHODS

From a spine archive, 144 cadaveric lumbar vertebrae (L1-L5) from 48 male human spines (mean age, 50 years) were scanned in air using micro-computed tomography to measure bone volume, bone mineral content (BMC) and BMD of the vertebral body, posterior elements, and entire vertebra. The contributions of the vertebral components to the total vertebral BMC and volume were compared, and the correlations between the BMC and BMD of the vertebrae and their components were examined.

RESULTS

Overall, the vertebral body contributed about one-third of the total vertebral BMC and two-thirds of the total vertebral volume, and the posterior elements contributed the remainder. The vertebral body BMC and BMD were poorly correlated to those of the posterior elements (r=0.39 for BMC and r=0.34 for BMD, p<.0001) and moderately correlated to the whole vertebra (r=0.77 and 0.75, respectively, p<.0001). The BMC and BMD of the posterior elements and whole vertebra were more strongly correlated (r=0.89 and 0.84, respectively, p<.0001).

CONCLUSIONS

The posterior elements are the primary contributor to vertebral BMC and BMD measurements. Dual-energy X-ray absorptiometry spine BMD measurements are likely to be more representative of the posterior elements than the targeted vertebral body. The findings elucidate the extent of the limitation of dual-energy X-ray absorptiometry spine BMD measurements.

Clinical performance of seven prescreening tools for osteoporosis in Iranian postmenopausal women

This study was designed to evaluate seven prescreening osteoporosis models in postmenopausal Iranian women. This study was performed on 8644 postmenopausal women who have been referred for bone mineral densitometry (BMD) in BMD center of Shariati hospital in Tehran between 2001 and 2011. Diagnostic properties of seven prescreening instruments were evaluated. With regard to area under curve (AUC), these models have low accuracy (AUC ≤ 0.65). Considering only femoral neck or total femur area, these models had low accuracy but were more sensitive. Except for three models with sensitivities of ≤65 % in both osteoporosis and fracture threshold, other models were around 70 % sensitive. However, these models were not considered clinically useful regarding their positive predictive values (PPV) especially in BMDs ≤02.5. With regard to different measures of diagnostic property, none of these models were good screening tools for osteoporosis or fracture threshold. Although some of them are sensitive, considering other measures such as PPV indicates that they are not completely useful for clinical use. Attempts should be made for developing newer prescreening methods and calibration of the existing models with regard to the studied population.

Effect of simulated early weight bearing on micromotion and pullout strength of uncemented distal femoral stems

The effect of simulated early weight bearing on both micromotion and pullout strength of uncemented distal femoral stems was evaluated in this study. The effect of stem endosteal contact and bone quality on implant pullout strength was also analyzed. A randomized matched-pair study was performed using 8 bilateral pairs of fresh human cadaveric femoral specimens. Each specimen pair was dual-energy x-ray absorptiometry scanned, uniformly implanted, fluoroscopically imaged, and randomly assigned to the cycled or uncycled group. The cycled group received 5000 cycles of axial compressive loading (to 700 N) and the contralateral side was not cycled. Micromotion was monitored during cycling and compared with a failure threshold (150 µm), and all implants underwent direct axial distraction (pullout) testing. During cycling, minimal micromotion was observed with an asymptotic decrease in differential motion between the first and last 50 cycles. Both cycled and uncycled groups demonstrated no statistical difference in average pullout force (4888±2124 N vs 4367±1154 N; P=.43). The percentage of cortical contact for each implant was determined from panoramic fluoroscopy images using digital image analysis software. Contact area for the distal third of the stem showed the highest correlation with pullout force and with predicting pullout force. Bone quality did not correlate with pullout force (r(2)=0.367) or stem contact area (r(2)=0.394). In sum, press-fit uncemented femoral stems did not loosen or demonstrate decreased pullout strength with early weight bearing simulated by cyclical axial compressive loading.

What analytic method should clinicians use to derive spine T-scores and predict incident fractures in men? Results from the MrOS study

In this study, the area under the curve was highest when using the lowest vertebral body T-score to diagnose osteoporosis. In men for whom hip imaging is not possible, the lowest vertebral body T-score improves the ability to diagnose osteoporosis in men who are likely to have an incident fragility fracture.

INTRODUCTION

Spine T-scores have limited ability to predict fragility fracture. We hypothesized that using lowest vertebral body T-score to diagnose osteoporosis would better predict fracture.

METHODS

Among men enrolled in the Osteoporotic Fractures in Men Study, we identified cases with incident clinical fracture (n = 484) and controls without fracture (n = 1,516). We analyzed the lumbar spine bone mineral density (BMD) in cases and controls (n = 2,000) to record the L1-L4 (referent), the lowest vertebral body, and International Society for Clinical Densitometry (ISCD)-determined T-scores using a male normative database and the L1-L4 T-score using a female normative database. We compared the ability of method to diagnose osteoporosis and, therefore, to predict incident clinical fragility fracture, using area under the receiver operator curves (AUCs) and the net reclassification index (NCI) as measures of diagnostic accuracy. ISCD-determined T-scores were determined in only 60 % of participants (n = 1,205).

RESULTS

Among 1,205 men, the AUC to predict incident clinical fracture was 0.546 for L1-L4 male, 0.542 for the L1-L4 female, 0.585 for lowest vertebral body, and 0.559 for ISCD-determined T-score. The lowest vertebral body AUC was the only method significantly different from the referent method (p = 0.002). Likewise, a diagnosis of osteoporosis based on the lowest vertebral body T-score demonstrated a significantly better net reclassification index (NRI) than the referent method (net NRI +0.077, p = 0.005). By contrast, the net NRI for other methods of analysis did not differ from the referent method.

CONCLUSION

Our study suggests that in men, the lowest vertebral body T-score is an acceptable method by which to estimate fracture risk.

Validation of the osteoporosis self-assessment tool in US male veterans

The osteoporosis self-assessment tool (OST) is a screening instrument that uses age and weight as parameters to predict the risk of osteoporosis. This study was designed to evaluate OST in predicting osteoporosis in males. Male veterans aged 50yr and older with no prior diagnosis of osteoporosis and no prior bone densitometry (dual-energy X-ray absorptiometry [DXA]) testing were eligible for the study. Sociodemographic information, medical history, and risk factors for osteoporosis were recorded. Anthropometric measurements were taken and DXA testing performed. The OST index for each subject was calculated and predictive values and receiver operating characteristic (ROC) curves were evaluated for OST and osteoporosis. Five hundred eighteen subjects underwent DXA, 92 (17.8%) had osteoporosis, 281 (54.2%) had low bone mass, and 145 (28.0%) had normal bone mineral density. The OST index ranged from -8 to 23 with a mean of 4 (standard deviation ± 4.3). An OST index of 6 or lower predicted osteoporosis with a sensitivity of 82.6%, specificity of 33.6%, and an area under the curve for the ROC curve of 0.67. OST index performed better in non-Hispanic whites and males >65 yr. OST predicts osteoporosis with moderate sensitivity and poor specificity in men.

Bone mineral density evaluation in osteoporosis: why yes and why not?

Osteoporosis is a diffuse skeletal disease in which a decrease in bone strength leads to an increased risk of fractures. A wide variety of types of bone densitometry measurements are available, including quantitative computed tomography measurements of the spine, quantitative ultrasound devices for measurements of the heel and other peripheral sites and dual-energy X-ray absorptiometry (DXA) for measurement of bone mineral density (BMD) at the lumbar spine, proximal femur, forearm and total body scans. Compared with alternative bone densitometry techniques, hip and spine DXA examinations have a number of advantages that include a consensus that BMD results can be interpreted using the World Health Organization T score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting anti-fracture therapies, and the ability to monitor response to treatment. However, in recent years, the authors have raised some important questions about the objective limits of this method that have led to doubts about its effectiveness in terms of clinical outcome.

Utility of spine bone mineral density in fracture prediction within FRAX

Predicting individuals at risk for fracturing and modifying that risk are important in preventative health. Our aim was to quantify the impact of spine bone mineral density (BMD) on fracture risk prediction and determine the positive predictive value of fracture prediction using the lowest BMD value at the femoral neck, total hip, or lumbar spine. A retrospective cross-sectional analysis of 15,033 women was performed, assessing the contribution of age, body mass index, number of clinical risk factors, T-score, and osteoporosis category to the presence of fracture. In patients whose lumbar spine T-scores are 1 or 2 osteoporosis categories lower than femoral neck, there is an approximately 30% increased risk of fracture compared with the femoral neck alone. For patients younger than 60 years, the odds ratio of having a fracture based on the presence of lumbar spine osteoporosis was greater than that based on femoral neck osteoporosis. Osteoporosis at the total hip correlated best with the presence of fracture. When using FRAX, we recommend that the 10-yr fracture prediction be adjusted when lumbar spine T-score is 1-2 osteoporosis categories lower than the femoral neck T-score or when lumbar spine T-score is ≥1 standard deviation less than femoral neck T-score.

Forearm bone mineral density measurement with different scanning positions: a study in right-handed Chinese using dual-energy X-ray absorptiometry

The purpose of our study was to determine whether different scanning positions influence forearm bone mineral density (BMD) measurements and to evaluate the association between forearm BMDs in different scanning positions and those of other skeleton sites. The study population consisted of 30 right-handed healthy Chinese volunteers. BMD was measured with GE Lunar Prodigy at the left forearm in both sitting and supine positions, and at lumbar spine and the right femur. All subjects received repeated measurements in the same day (repositioning), and the average of repeated BMD results was used for analysis. The BMD precision errors of the nondominant forearm in the sitting and supine positions varied from 1.13% to 2.46%. There were no statistically significant differences between BMD precision errors for each region of interest (ROI) between sitting and supine positions (all the p values were greater than 0.05). When comparing BMDs on the same side in the sitting position with those in the supine position, there were significant differences at both the 1/3 radius level and in the total radius (p<0.05). The BMD values at these ROIs obtained in the supine position were lower than those in the routine sitting position. The BMDs of the ultradistal radius in the both 2 different scanning positions were significantly associated with lumbar spine and femoral neck BMD, respectively. The total radius BMD in the different positions was associated with the BMD of the femoral neck. A change in body scanning position from sitting to supine will significantly influence forearm BMD results.

Joint Official Positions of the International Society for Clinical Densitometry and International Osteoporosis Foundation on FRAX(®). Executive Summary of the 2010 Position Development Conference on Interpretation and use of FRAX® in clinical practice

The International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) convened the FRAX(®) Position Development Conference (PDC) in Bucharest, Romania, on November 14, 2010, following a two-day joint meeting of the ISCD and IOF on the "Interpretation and Use of FRAX(®) in Clinical Practice." These three days of critical discussion and debate, led by a panel of international experts from the ISCD, IOF and dedicated task forces, have clarified a number of important issues pertaining to the interpretation and implementation of FRAX(®) in clinical practice. The Official Positions resulting from the PDC are intended to enhance the quality and clinical utility of fracture risk assessment worldwide. Since the field of skeletal assessment is still evolving rapidly, some clinically important issues addressed at the PDCs are not associated with robust medical evidence. Accordingly, some Official Positions are based largely on expert opinion. Despite limitations inherent in such a process, the ISCD and IOF believe it is important to provide clinicians and technologists with the best distillation of current knowledge in the discipline of bone densitometry and provide an important focus for the scientific community to consider. This report describes the methodology and results of the ISCD-IOF PDC dedicated to FRAX(®).

Measurements of bone mineral density in the lumbar spine and proximal femur using lunar prodigy and the new pencil-beam dual-energy X-ray absorptiometry

OBJECTIVE

We evaluated the correlation of the absolute bone mineral density (BMD) values of the lumbar spine and standard sites of the proximal femur obtained from a Lunar Prodigy and the newly developed pencil-beam dual-energy X-ray absorptiometry (Dexxum).

MATERIALS AND METHODS

Between June 2008 and December 2008, 79 Korean volunteers were enrolled. Measurements were obtained on the same day using both densitometers. The absolute BMD values (g/cm(2)) from the two densitometers were evaluated using Pearson's correlation analysis with Bonferroni's correction for the three clinically important sites. In order to evaluate precision, we performed duplicate Dexxum measurements, and calculated the within-subject coefficient of variation (WSCV).

RESULTS

The Pearson's correlation coefficient (r) of BMD values for the total proximal femur, femoral neck, and lumbar spine by the two densitometers were 0.926, 0.948, and 0.955 respectively, and the null hypotheses of r = 0.8 were all rejected (p < 0.001 by one-sided Z-test with Fisher's z-transformation for each site). The T-scores (r ≧ 0.842) and Z-scores (r ≧ 0.709) also showed strong positive correlations. The duplicate BMD values of Dexxum showed a high level of precision (WSCV ≦ 4.27%).

CONCLUSION

Dexxum measurements of BMD, T-scores, and Z-scores showed a strong linear correlation with those measured on Lunar Prodigy.

Comparison of antegonial index, mental index, panoramic mandibular index and mandibular cortical index values in the panoramic radiographs of normal males and male patients with osteoporosis

OBJECTIVE

The aim of the study was to compare the values of the antegonial index (AI), mental index (MI), panoramic mandibular index (PMI) and mandibular cortical index (MCI) in the panoramic radiographs of normal males and male patients with osteoporosis.

METHODS

In panoramic radiographs obtained from 40 male individuals (20 normal and 20 with osteoporosis), the mean was calculated for MI, AI, PMI and MCI index values measured in the right and left mandibles. The MI, AI and PMI index values were evaluated using the paired t-test, and MCI values were analysed using the chi(2) test.

RESULTS

MI (P < 0.001), AI (P < 0.01) and PMI (P < 0.05) values were significantly smaller in the group with osteoporosis; however, MCI (P > 0.05) was not significantly different.

CONCLUSION

MI, PMI and AI values, as radiomorphometric indices, were found to be smaller among male patients with osteoporosis, compared with normal patients in this study. It is suggested that these indices, used as an ancillary method in the diagnosis of osteoporosis in women, could also be useful for male patients. Further studies, of larger groups are needed on this subject, including of the MCI, which in this study showed no significant difference.

[Bone mineral density in patients with renal hyperparathyroidism undergoing surgery: relationship with bone parameters]

BACKGROUND AND OBJECTIVES

Hyperparathyroidism (HPT) in chronic kidney disease (CKD) may alter the composition and bone architecture, and cause fractures. The DEXA bone mineral density (BMD), used to predict fracture risk, measures the amount of calcium in bone. However, we do not know the relationship between BMD and bone composition.

PATIENT AND METHOD

Our study, conducted in two groups of renal patients with HPT who underwent parathyroidectomy (PTX): patients on hemodialysis (HD group) and patients with renal transplant (RT group). The aims were to quantify and value the differences among groups and by gender on bone mineral density, quantify and define differences between these two groups and a control group regarding the elemental composition of bone marrow biopsy obtained and static parameters of bone histomorphometry, and define a possible relationship between bone mineral density and bone elements versus histomorphometric parameters.

RESULTS

The BMD mean in femur was higher in TR group than in HD group. Linear correlation analysis performed between parameters versus BMD and bone histomorphometry elements, considering both TR and HD, only correlation between femur BMD (gr/cm2) and calcium (r=0.435, p=0.034, n=24) was observed.

CONCLUSION

Hyperparathyroidism patients undergoing renal transplant had better femoral BMD than those on hemodialysis; the trabecular volume was lower in kidney transplantation, while the volume of fibrosis was higher in hemodialysis patients; the elements in bone transplant and hemodialysis were in similar proportion, while the calcium content tended to be higher in renal transplant.