Vertebral microarchitecture and fragility fracture in men: a TBS study

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

INTRODUCTION/BACKGROUND

Trabecular bone score (TBS) is an indirect measurement of bone quality and microarchitecture determined from dual-energy X-ray absorptiometry (DXA) imaging of the lumbar spine. TBS predicts fracture risk independent of bone mass/density, suggesting this assessment of bone quality adds value to the understanding of patients' bone health. While lean mass and muscular strength have been associated with higher bone density and lower fracture risk among older adults, the literature is limited regarding the relationship of lean mass and strength with TBS. The purpose of this study was to determine associations of DXA-determined total body and trunk lean mass, maximal muscular strength, and gait speed as a measure of physical function, with TBS in 141 older adults (65-84 yr, 72.5 +/- 5.1 yr, 74% women).

METHODOLOGY

Assessments included lumbar spine (L1-L4) bone density and total body and trunk lean mass by DXA, lower body (leg press) and upper body (seated row) strength by one repetition maximum tests, hand grip strength, and usual gait speed. TBS was derived from the lumbar spine DXA scan. Multivariable linear regression determined the contribution of proposed predictors to TBS.

RESULTS

After adjusting for age, sex, and lumbar spine bone density, upper body strength significantly predicted TBS (unadjusted/adjusted R2= 0.16/ 0.11, β coefficient =0.378, p=0.005), while total body lean mass index showed a trend in the expected direction (β coefficient =0.243, p=0.053). Gait speed and grip strength were not associated with TBS (p>0.05).

CONCLUSION

Maximum strength of primarily back muscles measured as the seated row appears important to bone quality as measured by TBS, independent of bone density. Additional research on exercise training targeting back strength is needed to determine its clinical utility in preventing vertebral fractures among older adults.

Male osteoporosis

Osteoporosis, a disease classically attributed to postmenopausal women, is underappreciated, underdiagnosed, and undertreated in men. However, it is not uncommon for osteoporotic fractures to occur in men. About 40% of fractures occur in men with an incidence that has increased over the years. After a first fracture, the risk of a subsequent episode, as well as the risk of death, is higher in the male than in the female population. Despite these facts, only 10% of men with osteoporosis receive adequate treatment. Up to half of the cases of male osteoporosis have a secondary cause, the most common being hypogonadism, excessive alcohol consumption, and chronic use of glucocorticoids. The International Society for Clinical Densitometry (ISCD) recommends using the female database for the diagnosis of osteoporosis by DXA (T-score ≤ -2.5 in men over 50 years old). In addition, osteoporosis can also be diagnosed independently of the BMD if a fragility fracture is present, or if there is a high risk of fractures by FRAX. Treatment is similar to postmenopausal osteoporosis, because the data regarding changes in bone density track closely to those in women. Data concerning fracture risk reduction are not as certain because the clinical trials have included fewer subjects for shorter period of time. In men with symptomatic hypogonadism, testosterone replacement, if indicated, can improve BMD.

Bone microstructure evaluated by TBS and HR-pQCT in Chinese adults with X-linked hypophosphatemia

X-linked hypophosphatemia (XLH) is the most common form of heritable hypophosphatemic rickets. Although generalized mineralization defects have been observed, elevated areal bone mineral density (aBMD) in the lumbar spine measured by dual-energy X-ray absorptiometry (DXA) has also been found in XLH. In contrast, high-resolution peripheral quantitative computed tomography (HR-pQCT) revealed lower volumetric BMD (vBMD) and damaged bone microstructure in the peripheral bone in XLH. Trabecular bone score (TBS), which can assess the trabecular microstructure in the lumbar spine, has not been explored in XLH. This study aimed to explore TBS and its correlations with biochemical indices and HR-pQCT parameters in adult XLH patients. A total of 66 patients with XLH (26 men and 40 women) aged 29.6 ± 9.6 years and 66 age- and sex-matched healthy controls were included. Z score of lumbar spine aBMD was relatively high [2.0 (0.6, 3.7)], with normal TBS (1.475 ± 0.129) in the XLH patients. HR-pQCT revealed larger total and trabecular area in the peripheral bone in the XLH group compared with the control group. In addition, lower trabecular and cortical vBMD, lower trabecular number with greater separation, and lower bone strength at both the radius and tibia were found in the XLH group compared with the control group. Smaller cortical area, lower thickness and higher porosity in the XLH group compared with controls were only found at the radius. TBS was not associated with any biochemical indices, while better HR-pQCT parameters correlated with higher serum phosphate and lower ALP levels. TBS was positively related with aBMD but not HR-pQCT parameters. In conclusion, adult patients with XLH had high bone mass and normal TBS in the lumbar spine but compromised microarchitecture and bone strength in the peripheral bone. This finding indicated a site-specific effect of the disease on the skeleton in the XLH patients.

Trabecular bone score in people with cystic fibrosis

People with cystic fibrosis (CF) are at increased risk of fractures. Our study found that low trabecular bone score (TBS) (a measure of bone strength) may help identify people with CF at risk of fractures especially when combined with bone density measured by DXA, age, hemoglobin A1c, and transplant status.

INTRODUCTION

People with cystic fibrosis (CF) are at increased risk of fractures. This study aims to evaluate the association of trabecular bone score (TBS) with fractures in CF.

METHODS

A cross-sectional study of adults with CF who completed bone density between 2009 and 2019. TBS was applied to lumbar spine studies.

RESULTS

A total of 202 people with CF were included. A history of fracture was present in 36 (17.8%) subjects. Patients with history of fractures had higher hemoglobin A1c (A1C) (7.8 ± 2.7% vs. 6.7 ± 1.7%, p = 0.024), lower femoral neck (FN) Z/T-score (- 1.05 ± 1.08 vs. - 0.44 ± 1.08, p = 0.012), and lower TBS (1.36 ± 0.13 vs. 1.40 ± 0.11, p = 0.05) compared to those without. Lung transplant recipients had a higher prevalence of fractures (50% vs. 14.1%, p < 0.001). The odds ratio (95%CI) of having a fracture for subjects with TBS (≤ 1.2 vs. > 1.2) stratified by FN Z/T-score (≤ - 2.0 or >  - 2.0) was 3.88 (0.92, 16.35), p = 0.07. ROC analysis showed TBS was significantly associated with fractures (p < 0.05); however, FN BMD was superior. A model combining FN BMD, age, A1c, transplant, and TBS improved ROC compared to FN BMD + age (0.837 vs. 0.779, p = 0.031).

CONCLUSIONS

TBS ≤ 1.2 may identify people with CF at high risk of fractures. A model combining FN BMD, age, A1c, transplant, and TBS was significantly associated with fractures compared to FN BMD + age. Future studies are needed to evaluate the prediction of fractures in people with CF using clinical and bone parameters.

Bone Mineral Density and Trabecular Bone Score in Predicting Vertebral Fractures in Male Employees of the Electricity Generating Authority of Thailand

PURPOSE

Osteoporotic VF is frequently asymptomatic and affects not only women but also men. Identifying patients at risk is essential for early management and prevention. BMD and the TBS are measurements of bone strength and trabecular microarchitecture, respectively. Their role in VF prediction in men is less well-studied. We determined the BMD and TBS predictive ability for osteoporotic VF in men.

METHODS

A total of 115 male participants of the Electricity Generating Authority of Thailand (EGAT) cohorts without a history of VF who completed the baseline BMD and TBS measurements in 2012 and a thoracolumbar spine radiograph in 2017 were recruited. The VF was assessed using the Genant semiquantitative method. Logistic regression analysis was performed to identify factors associated with the fracture. The area under the receiving operator curve (AUC) was analyzed to define VF predictive ability.

RESULTS

Forty subjects (34.78%) had VFs. The unadjusted relative risks (95% confidence interval) for VF for one standard deviation decrease in the TBS and low TBS were 1.319 (1.157-1.506) and 2.347 (1.496-3.682), respectively, and remained significant after BMD and age adjustment. For VF prediction, combined models had a greater AUC than models predicted from a single variable. The use of low TBS, femoral neck BMD, and age provided the best AUC (0.693).

CONCLUSION

BMD and the TBS could predict osteoporotic VF in male EGAT employees. The use of both BMD and the TBS in the VF prediction process improved predictive ability.

Usefulness of the Trabecular Bone Score in Assessing the Risk of Vertebral Fractures in Patients with Cirrhosis

The trabecular bone score (TBS), a surrogate measure of bone microarchitecture, provides complementary information to bone mineral density (BMD) in the assessment of osteoporotic fracture risk. This cross-sectional study aimed to determine whether TBS can identify patients with liver cirrhosis that are at risk of vertebral fractures. We enrolled 275 patients who completed evaluations for lumbar BMD, TBS, and vertebral fractures between November 2018 and April 2021. BMD was measured using dual-energy X-ray absorptiometry (DXA), TBS was calculated by analyzing DXA images using TBS iNsight software, and vertebral fractures were evaluated using Genant’s semi-quantitative method with lateral X-ray images. Factors associated with vertebral fractures and their correlation with the TBS were identified using regression models. Of the enrolled patients, 128 (47%) were female, the mean age was 72 years, and 62 (23%) were diagnosed with vertebral fractures. The prevalence of vertebral fractures was higher in women than in men (33% vs. 14%; p < 0.001). The unadjusted odds ratio (OR) of the vertebral fractures for one standard deviation decrease in TBS and BMD was 2.14 (95% confidence interval [CI], 1.69−2.73) and 1.55 (95% CI, 1.26−1.90), respectively. After adjusting for age, sex, and BMD, the adjusted OR of the vertebral fractures in TBS was 2.26 (95% CI, 1.52−3.35). Multivariate linear regression analysis showed that TBS was independently correlated with age (β = −0.211), body mass index (β = −0.251), and BMD (β = 0.583). TBS can help identify patients with cirrhosis at risk of vertebral fractures.

Similarities and differences between bone quality parameters, trabecular bone score and femur geometry

Bone quality is a critical factor that, along with bone quantity, determines bone strength. Image-based parameters are used for assessing bone quality non-invasively. The trabecular bone score (TBS) is used to assess quality of trabecular bone and femur geometry for cortical bone. Little is known about the associations between these two bone quality parameters and whether they show differences in the relationships with age and body mass index (BMI). We investigated the associations between the trabecular bone score (TBS) and femur cortical geometry. Areal bone mineral density (BMD) was assessed using dual energy X-ray absorptiometry (DXA) and the TBS was assessed using iNsight software and, femur geometry using APEX (Hologic). A total of 452 men and 517 women aged 50 years and older with no medical history of a condition affecting bone metabolism were included. Z-scores for TBS and cortical thickness were calculated using the age-specific mean and SD for each parameter. A ‘discrepancy group’ was defined as patients whose absolute Z-score difference between TBS and cortical thickness was > 1 point. TBS and cortical thickness correlated negatively with age both in men and women, but the associations were stronger in women. Regarding the associations with BMI, TBS provided significant negative correlation with BMI in the range of BMI > 25 kg/m². By contrast, cortical thickness correlated positively with BMI for all BMI ranges. These bone quality-related parameters, TBS and cortical thickness, significantly correlated, but discordance between these two parameters was observed in about one-third of the men and women (32.7% and 33.4%, respectively). Conclusively, image-based bone quality parameters for trabecular and cortical bone exhibit both similarities and differences in terms of their associations with age and BMI. These different profiles in TBS and FN cortical thickness might results in different risk profiles for the vertebral fractures or hip fractures in a certain percentage of people.

Advances in the Bone Health Assessment of Children

The last 2 decades have seen tremendous growth in understanding the clinical characteristics of various childhood bone disorders, their mechanisms and natural histories, and their responses to treatment. In this review, the authors describe advances in bone assessment techniques for children. In addition, they provide their skeletal site-specific applications, underscore the principles that are relevant to the biology of the growing child, show how these methods assist in the diagnosis and management of pediatric bone diseases, and highlight how these techniques have shed light on bone development and underlying disease mechanisms.

Effect of Trabecular Microstructure of Spinous Process on Spinal Fusion and Clinical Outcomes After Posterior Lumbar Interbody Fusion: Bone Surface/Total Volume as Independent Favorable Indicator for Fusion Success

OBJECTIVE

We assessed the trabecular microarchitecture of the spinous process as an autograft and investigated its correlations with fusion success and clinical outcomes for patients undergoing posterior lumbar interbody fusion.

METHODS

Micro-computed tomography reconstruction techniques were used to scan cancellous bone specimens from spinous processes. We then measured the microarchitectural parameters for 105 subjects.

RESULTS

The patient cohort included 44 older men and 61 postmenopausal women with a minimum of 2-year follow-up data available. The complete fusion rate was 87.6% (92 of 105) at the last follow-up. When stratified by fusion status, the union group had significantly greater bone surface/total volume (BS/TV) and trabecular number but significantly lower trabecular separation than the nonunion group. No statistically significant differences were observed between the 2 groups in the clinical variables, except for the bone mineral density at the femoral neck (P = 0.028). On binomial logistic regression analysis, BS/TV was identified as an independent predictor for fusion success (odds ratio, 8.532; P = 0.032). The receiver operating characteristic curve showed that BS/TV had excellent performance in predicting successful fusion (area under the curve, 0.807). Using a cutoff value for BS/TV of 3.145, a greater BS/TV was significantly associated with visual analog scale scores for lower back pain 6 months postoperatively and lower Oswestry disability index scores at 12 and 24 months postoperatively but not with visual analog scale scores for leg pain.

CONCLUSIONS

Our data suggest that microstructural deterioration of the spinal process as an autograft has detrimental effects on spinal fusion and clinical outcomes for patients undergoing instrumented posterior lumbar interbody fusion. Specifically, the microstructural parameter BS/TV has good potential for assessing lumbar bone quality and predicting fusion success.

Older Age and Higher Body Mass Index Are Associated With a More Degraded Trabecular Bone Score Compared to Bone Mineral Density

Trabecular bone score (TBS) may detect subjects with a more degraded microarchitecture but whose bone mineral density (BMD) reflects normal or osteopenia. The purpose of this study was to evaluate whether age and body sizes were associated with the discordance between BMD and TBS. We analyzed BMD and TBS in 1505 Korean women over 40 yr of age who had no history of osteoporotic fractures or conditions that affect bone metabolism. We considered 3 groups to have TBS values that reflected a more degraded TBS than their BMD values: (1) normal BMD but partially degraded TBS, (2) normal BMD but degraded TBS, and (3) osteopenia but degraded TBS. We compared subjects in these 3 groups with other subjects in terms of age and body sizes, and used multivariable logistic regression to analyze the odds ratios (ORs) for the occurrence of a more degraded TBS than their BMD level using age and body mass index (BMI). One hundred sixty subjects (10.6%) were found to have a more degraded TBS than their BMD level; these subjects were older, heavier, and had higher BMIs than the other subjects. Age (OR: 1.038, 95% confidence interval: 1.020-1.057, p< 0.001) and BMI (OR: 1.223, 95% confidence interval: 1.166-1.283, p< 0.001) were statistically significant in the multivariable analysis for the occurrence of this feature. Women with a more degraded TBS than their BMD level are older and have higher BMIs than the other subjects. It may be helpful to consider the possibility of trabecular bone degradation when clinically evaluating fracture risk in patients who are older or who have high BMIs with normal BMD or osteopenia.

VITamin D and OmegA-3 TriaL (VITAL) bone health ancillary study: clinical factors associated with trabecular bone score in women and men

We investigated the association of clinical variables with TBS at baseline in the bone health sub-cohort of the VITamin D and OmegA-3 TriaL (VITAL). Lower TBS was associated with female sex, aging, BMI ≥ 25 kg/m², SSRI use, high alcohol intake, and presence of diabetes; there was a trend towards significance between lower TBS and history of fragility fractures.

INTRODUCTION

We investigated whether TBS differs by sex, race, body mass index (BMI), and other clinical variables.

METHODS

The VITamin D and OmegA-3 TriaL (VITAL) is determining effects of vitamin D₃ and/or omega-3 fatty acid (FA) supplements in reducing risks of cancer and cardiovascular disease. In the VITAL: Effects on Bone Structure/Architecture ancillary study, effects of these interventions on bone will be investigated. Here, we examine the associations of clinical risk factors with TBS assessments at baseline in the bone health sub-cohort, comprised of 672 participants (369 men and 303 women), mean (± SD) age 63.5 ± 6.0 years; BMI ≤ 37 kg/m², no bisphosphonates within 2 years or other bone active medications within 1 year.

RESULTS

TBS was greater in men than women (1.311 vs. 1.278, P < 0.001) and lower with elevated BMIs (P < 0.001), higher age (P = 0.004), diabetes (P = 0.008), SSRI use (P = 0.044), and high alcohol intake (P = 0.009). There was a trend for history of fragility fractures (P = 0.072), and lower TBS. TBS did not vary when analyzed by race, smoking, history of falls, and multivitamin or caffeine use.

CONCLUSIONS

Lower TBS was associated with female sex, aging, BMI ≥ 25 kg/m², SSRI use, alcohol use, and presence of diabetes; there was a trend between lower TBS and history of fragility fractures. TBS may be useful clinically to assess structural changes that may be associated with fractures among patients who are overweight or obese, those on SSRIs, or with diabetes. Ongoing follow-up studies will clarify the effects of supplemental vitamin D₃ and/or FA's on TBS and other bone health measures.

TRIAL REGISTRATION

NCT01747447.

The effect of metformin versus placebo in combination with insulin analogues on bone mineral density and trabecular bone score in patients with type 2 diabetes mellitus: a randomized placebo-controlled trial

Some antihyperglycemic medications have been found to affect bone metabolism. We assessed the long-term effects of metformin compared with placebo on bone mineral density (BMD) and trabecular bone score (TBS) in patients with type 2 diabetes. Metformin had no significant effect on BMD in the spine and hip or TBS compared with a placebo.

INTRODUCTION

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fractures despite a high bone mass. Some antihyperglycemic medications have been found to affect bone metabolism. We assessed the long-term effects of metformin compared with placebo on bone mineral density (BMD) and trabecular bone score (TBS).

METHODS

This was a sub-study of a multicenter, randomized, 18-month placebo-controlled, double-blinded trial with metformin vs. placebo in combination with different insulin regimens (the Copenhagen Insulin and Metformin Therapy trial) in patients with T2DM. BMD in the spine and hip and TBS in the spine were assessed by dual-energy X-ray absorptiometry at baseline and after 18 months follow-up.

RESULTS

Four hundred seven patients were included in this sub-study. There were no between-group differences in BMD or TBS. From baseline to 18 months, TBS decreased significantly in both groups (metformin group, - 0.041 [- 0.055, - 0.027]; placebo group - 0.046 [- 0.058, - 0.034]; both p < 0.001). BMD in the spine and total hip did not change significantly from baseline to 18 months. After adjustments for gender, age, vitamin D, smoking, BMI, duration of T2DM, HbA1c, and insulin dose, the TBS between-group differences increased but remained non-significant. HbA_1c was negatively associated with TBS (p = 0.009) as was longer duration of diabetes, with the femoral neck BMD (p = 0.003). Body mass index had a positive effect on the hip and femoral neck BMD (p < 0.001, p = 0.045, respectively).

CONCLUSIONS

Eighteen months of treatment with metformin had no significant effect on BMD in the spine and hip or TBS in patients with T2DM compared with a placebo. TBS decreased significantly in both groups.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT00657943).

The trabecular bone score is associated with bone mineral density, markers of bone turnover and prevalent fracture in patients with end stage kidney disease

Fracture risk increases in end-stage kidney disease (ESKD), but bone mineral density (BMD) measurement is less predictive of risk than in the general population. In this study of patients with ESKD, a lower trabecular bone score (TBS), indicative of microarchitectural deterioration, was associated with higher bone turnover markers and prevalent non-vertebral fracture.

INTRODUCTION

Declining renal function carries increased fracture risks, but BMD is less predictive of fracture for dialysis patients than the general population. The TBS, obtained from lumbar spine dual-energy X-ray absorptiometry (DXA) images, provides information on microarchitectural integrity not captured by BMD. The aim of this study was to assess associations of the TBS to clinical, DXA, radiological, and laboratory measures in patients with ESKD undergoing kidney and simultaneous pancreas kidney (SPK) transplantation.

METHODS

A total of 147 patients with ESKD underwent pre-transplant laboratory testing, DXA, lateral spine X-ray, and structured history within 4 weeks of transplantation. Associations of the TBS to demographic data, prevalent fracture, BMD, and laboratory variables were assessed.

RESULTS

Of 147 patients (60% male, mean age 48 ± 13 years), 36% had diabetes mellitus (DM) and 54 patients had fractures: 21 prevalent vertebral fractures only, 22 non-vertebral fractures only, and 11 had both. The mean TBS (1.345 ± 0.125) was lower in patients undergoing SPK than kidney-only transplants (1.292 vs. 1.364, p = 0.001). The TBS correlated to spine and total hip BMD, body mass index and inversely to parathyroid hormone, alkaline phosphatase and procollagen 1 N-propeptide. By multivariable logistic regression, lower TBS was significantly associated to prior non-vertebral fracture (p = 0.026).

CONCLUSIONS

A lower TBS, suggestive of increased microarchitectural damage, was associated with type 1 DM, markers of higher bone turnover, and prevalent fracture. These data support the need for prospective studies to evaluate whether TBS inclusion improves fracture prediction in patients with ESKD.

Trabecular bone score (TBS) is associated with sub-clinical vertebral fractures in HIV-infected patients

Fragility fractures risk is increased among HIV infected patients. Bone microstructure alterations, in addition to bone mineral density (BMD) reduction, might be responsible for the increased risk. The aim of this study was to determine the prevalence of vertebral fractures (VFs) and their association with trabecular bone score (TBS), an indirect index of bone microstructure, in a cohort of HIV-infected subjects. One-hundred and forty-one HIV-infected patients (87% males, median age 43 years, 94% on stable antiretroviral therapy with undetectable viral load) underwent viro-immunological and bone metabolism biochemical screenings. Lumbar TBS and BMD at femoral neck, total hip, and lumbar spine, were measured with dual-energy X-ray absorptiometry (DXA). VFs were identified using the semiquantitative method and quantitative morphometric analysis from thoracic and lumbar spine X-ray images. VFs were observed in 19 patients (13.5%). BMD was below the expected range for age in 18 (12.8%) subjects. No significant differences were found stratifying VFs prevalence by BMD, whereas patients with lower TBS showed a higher prevalence of VFs (p = 0.03). In multivariate analysis, TBS was the only factor significantly associated to VFs (OR = 0.56; 95% CI = 0.33-0.96; p = 0.034), with increased fracture risk for lower TBS values. VFs are prevalent and associated with low TBS among HIV-positive patients, whereas no significant association was found with BMD.

The Trabecular Bone Score (TBS) Complements DXA and the FRAX as a Fracture Risk Assessment Tool in Routine Clinical Practice

PURPOSE OF THE REVIEW

There is an increasing body of evidence that the trabecular bone score (TBS), a surrogate of bone microarchitecture extracted from spine DXA, could play an important role in the management of patients with osteoporosis or at risk of fracture. The current paper reviews this published body of scientific literature on TBS and answers the most relevant clinical questions.

RECENT FINDINGS

TBS has repeatedly been proven to be predictive of fragility fractures, current and future, and this is largely independent of BMD, CRF, and the FRAX, and when used in conjunction with any one of these measures, it consistently enhances their accuracy. There also is a growing body of evidence indicating that the TBS has particular advantages over BMD for specific causes of increased fracture risk, like chronic corticosteroid excess, type-2 diabetes, and chronic kidney disease, and patients being treated with anti-aromatase and primary hyperparathyroidism, conditions wherein BMD readings are often misleading. TBS enhances performance of the FRAX tool, where its greatest utility appears to lie in its ability to accurately classify those patients whose BMD level lies close to the intervention threshold, aiding in decisions on whether treatment is warranted or not. Furthermore, TBS has also particular advantages over BMD in secondary osteoporosis. While the role of TBS with monitoring could be important as the different molecules impact logically TBS to various degrees, large clinical trials are still needed.

Utility of trabecular bone score in the evaluation of osteoporosis

PURPOSE OF REVIEW

Trabecular bone score (TBS) is a lumbar spine dual-energy absorptiometry texture index which provides information on skeletal quality partially independent of bone mineral density (BMD). A body of work has emerged demonstrating the relationship between TBS and fracture risk, with lower TBS values associated with increased risk for osteoporotic fracture in postmenopausal women and older men. TBS is derived from standard DXA images; however, the information provided by TBS is complementary to that provided by BMD. In this article, we review the current state of TBS and its evolving role in the assessment and management of osteoporosis, with particular emphasis on the literature of the previous year.

RECENT FINDINGS

TBS-adjusted The Fracture Risk Assessment tool (FRAX) probabilities enhance fracture risk prediction compared with conventional FRAX predictions. TBS has been found to better categorize fracture risk and assists in FRAX-based treatment decisions, particularly for patients close to an intervention threshold. However, change in lumbar spine TBS while undergoing antiresorptive treatment is not a useful indicator of antifracture effect.

SUMMARY

Lumbar spine TBS is a recently developed image-based software technique for skeletal assessment, complementary to conventional BMD, which has been shown to be clinically useful as a fracture risk prediction tool.

Effects of Teriparatide, Denosumab, or Both on Spine Trabecular Microarchitecture in DATA-Switch: a Randomized Controlled Trial

In postmenopausal women, 2 yr of combined teriparatide and denosumab increases bone mineral density more than either drug alone, and switching from either combination or teriparatide to denosumab for an additional 2 yr further increases bone mineral density. Conversely, switching from denosumab to teriparatide results in transient bone loss. The effects of these interventions on spine microarchitecture are unknown. In the DATA and DATA-Switch studies, 94 postmenopausal osteoporotic women were randomized to receive 24 mo of teriparatide (20 µg daily), denosumab (60 mg every 6 mo), or both. Then, women originally assigned to 24 mo of teriparatide received 24 mo of denosumab, whereas subjects originally randomized to 24 mo of denosumab received 24 mo of teriparatide. Subjects who received both drugs received an additional 24 mo of denosumab alone. Spine trabecular bone score (TBS, a gray-level textural assessment of bone microarchitecture) was measured blinded from treatment groups using images from 2-dimensional dual-energy X-ray absorptiometry spine scans at 0, 12, 24, 30, 36, and 48 mo in 65 women who had posterior-anterior spine dual-energy X-ray absorptiometry images suitable for TBS analysis. After 24 mo, TBS increased by 2.7 ± 4.7% in the teriparatide group (p = 0.009 vs baseline), by 1.8 ± 5.0% in the denosumab group (p = 0.118 vs baseline), and by 4.5 ± 6.7% in the combination group (p = 0.017 vs baseline), with no significant between-group differences. In the 6 mo after the treatments were switched (months 24-30), TBS continued to increase in the combination-to-denosumab and teriparatide-to-denosumab groups but decreased by -1.1 ± 4.0% in the denosumab-to-teriparatide group (p < 0.05 vs other groups). After 48 mo, compared to month 0, TBS increased by 5.1 ± 5.8% in the teriparatide-to-denosumab group, by 3.6 ± 4.2% in the denosumab-to-teriparatide group, and by 6.1 ± 4.7% in the combination-to-denosumab group (p < 0.001 vs baseline for all groups, p = not significant for between-group differences). Switching from teriparatide to denosumab also increased spine TBS. Conversely, switching from denosumab to teriparatide transiently degraded spine trabecular microarchitecture, the clinical consequences of which require further study.

The main autoimmune and nonautoimmune etiologies of endogenous hyperthyroidism do not seem to influence the increased prevalence of morphometric vertebral fractures and osteoporosis in Portuguese men

OBJECTIVES

The purpose of this study was to evaluate the effects of hyperthyroidism and their etiology on bone mineral density (BMD), on body soft tissue composition, on the prevalence of vertebral fractures detected by vertebral fracture assessment (VFA) and on the trabecular bone score (TBS).

METHODS

From an initial population of 119 Portuguese men (78 with hyperthyroidism [HT]+ 41 controls [CTs]) admitted to the Endocrinology Department we selected 41 men aged over 50 with clinical hyperthyroidism to participate; each one was matched by age and height with a control person. BMD (g/cm2) at the lumbar spine, hip, radius 33% and whole body and the total body masses (kg) were studied by dual-energy X-ray absorptiometry (DXA). VFA with Genant semiquantitative method was used to detect fractures. The TBS was obtained from lumbar spine DXA images. No patient had been treated previously for hyperthyroidism or osteoporosis. Adequate statistical tests were used.

RESULTS

In the hyperthyroidism group, total lean mass (CT 58.16 ± 7.7 vs. HT 52.3 ± 5.7, P = 0.03) and distal radius BMD (CT 0.769 ± 0.05 vs. HT 0.722 ± 0.08, P = 0.005) were lower; there was a significantly higher prevalence of osteoporosis (CT 9.7% vs. HT 29.3%, P = 0.015) and vertebral fractures (CT 2.4% vs. HT 24.4%, P = 0.007). TBS was similar in both groups (CT 1.328 ± 0.11 vs. HT 1.356 ± 0.11, P = not significant). Comparing patients with Graves' disease with patients with toxic goiter, there were no differences regarding BMD, BMD qualification, prevalence of fractures and TBS and just total lean mass was significantly lower in patients with Graves' disease.

CONCLUSIONS

These results suggest that in a group of hyperthyroid men aged over 50 there are significant decreases in cortical bone BMD and lean mass and a higher prevalence of osteoporosis and silent vertebral fractures, but the etiology of the hyperthyroidism does not seem to influence it. Besides the antithyroid drugs, some patients may benefit from bone-directed treatments.

Use of Trabecular Bone Score (TBS) as a Complementary Approach to Dual-energy X-ray Absorptiometry (DXA) for Fracture Risk Assessment in Clinical Practice

Osteoporosis is a common bone disease characterized by low bone mass and altered bone microarchitecture, resulting in decreased bone strength with an increased risk of fractures. In clinical practice, physicians can assess the risk of fracture for a patient based on several risk factors. Some such as age, weight, and history of fractures after 50 years of age, parental fracture, smoking status, and alcohol intake are incorporated into FRAX, an assessment tool that estimates the 10-year probability of hip fracture and major osteoporotic fractures based on the individual's risk factors profile. The diagnosis of osteoporosis is currently based on bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry scans. Among other widely recognized limitations of BMD is that BMD considers only the density of the bone and fails in measuring bone microarchitecture, for which novel techniques, such as trabecular bone score (TBS), have been developed. TBS is a texture parameter related to bone microarchitecture that may provide skeletal information that is not captured from the standard BMD measurement. Several studies have examined the value of TBS on predicting osteoporotic fractures. Our study aimed to summarize a review of the current scientific literature with focus on fracture risk assessment and to present both its findings and its conclusions regarding how and when TBS should be used. The existing literature indicates that low lumbar spine TBS is associated with a history of fracture and the incidence of new fracture. The effect is largely independent of BMD and of sufficient magnitude to enhance risk stratification with BMD. The TBS effect is also independent of FRAX, with likely greatest utility for those individuals whose BMD levels lie close to an intervention threshold. The clinical and scientific evidence supporting the use of TBS, with the ability of this technology to be seamlessly integrated into a daily workflow, makes TBS an attractive and useful clinical tool for physicians to improve patient management in osteoporosis. Further research is ongoing and necessary to further clarify the role of TBS in additional specific disorders.

Trabecular Bone Score: A New DXA-Derived Measurement for Fracture Risk Assessment

Trabecular bone score (TBS) is a novel method that assesses skeletal texture from spine dual-energy X-ray absorptiometry (DXA) images. TBS improves fracture-risk prediction beyond that provided by DXA bone mineral density (BMD) and clinical risk factors, and can be incorporated to the Word Health Organization Fracture Risk Assessment tool (FRAX®) to enhance fracture prediction. There is insufficient evidence that TBS can be used to monitor treatment with bisphosphonates. TBS may be particularly helpful to assess fracture risk in diabetes. This article reviews technical and clinical aspects of TBS and its potential utility as a clinical tool to predict fracture risk.

Bone Health in Athletes

CONTEXT

The health of the skeletal system is important for athletes young and old. From the early benefits of exercise on bones to the importance of osteoporosis prevention and treatment, bone health affects the ability to be active throughout life.

EVIDENCE ACQUISITION

PubMed articles dating from 1986 to 2016 were used for the review. Relevant terms such as keywords and section titles of the article were searched and articles identified were reviewed for relevance to this article.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Levels 1 through 4 evidence included.

RESULTS

There is strong evidence that exercise benefits bone health at every age and is a critical factor in osteoporosis prevention and treatment. Vitamin D, calcium, and hormones play vital roles in ensuring optimal bone health. When there is an imbalance between exercise and nutrition, as seen in the female athlete triad, bone health is compromised and can lead to bone stress injuries and early osteoporosis. Both of these can lead to morbidity and lost time from training and competition. Thus, early recognition and appropriate treatment of the female athlete triad and other stress fracture risk factors are vital to preventing long-term bone health problems.

CONCLUSION

To optimize bone health, adequate nutrition, appropriate weightbearing exercise, strength training, and adequate calcium and vitamin D are necessary throughout life.

Assessment of trabecular bone score (TBS) in overweight/obese men: effect of metabolic and anthropometric factors

The "trabecular bone score" (TBS) indirectly explores bone quality, independently of bone mineral density (BMD). We investigated the effects of anthropometric and metabolic parameters on TBS in 87 overweight/obese men. We assessed BMD and TBS by DXA, and some parameters of glucose metabolism, sex-and calciotropic hormone levels. Regression models were adjusted for either age and BMI, or age and waist circumference, or age and waist/hip ratio, also considering BMI >35 (y/n) and metabolic syndrome (MS) (y/n). Correlations between TBS and parameters studied were higher when correcting for waist circumference, although not significant in subjects with BMI >35. The analysis of covariance showed that the same model always had a higher adjusted r-square index. BMD at lumbar spine and total hip, fasting glucose, bioavailable testosterone, and sex hormone-binding globulin are the only covariates having a significant effect (p < 0.05) on the variations of TBS. The presence of MS negatively affected only the association between TBS and BMD at total hip. We did not find any significant effect of BMI >35 on TBS values or significant interaction terms between each covariate and either BMI >35 or the presence of MS. Obesity negatively affected TBS, despite unchanged BMD. Alterations of glucose homeostasis and sex hormone levels seem to influence this relationship, while calciotropic hormones have no role. The effect of waist circumference on TBS is more pronounced than that of BMI.

The Association Between Trabecular Bone Score and Lumbar Spine Volumetric BMD Is Attenuated Among Older Men With High Body Mass Index

Trabecular bone score (TBS) has been proposed as a dual-energy X-ray absorptiometry (DXA) derived measure of underlying quality of trabecular bone; however, TBS is not considered valid for those with body mass index (BMI) >37 kg/m² . Our objective was to determine the association between TBS and lumbar spine (trabecular) volumetric BMD (LS-VBMD) and to examine whether the association varied by BMI and body composition among older men below this clinical threshold. We used regression models to study 3479 men age ≥65 years enrolled in the Osteoporotic Fractures in Men (MrOS) study who had TBS from spine DXA scans, LS-VBMD from central quantitative computed tomography, measures of trunk fat and lean mass from DXA, and BMI <37 kg/m² . TBS was categorized as normal (n = 925), partially degraded (n = 1747), and degraded (n = 807). TBS was inversely related to BMI, trunk fat mass, and trunk lean mass (all p < 0.001). The relationship between TBS and LS-VBMD was nonlinear with magnitude of effect (slope of regression line using standardized variables) ranging from 0.07 (95% CI, -0.02 to 0.15) among those with degraded TBS up to 0.71 (95% CI, 0.54 to 0.89) among those with normal TBS. The relationship was still nonlinear after adjusting for age, clinical site, and either BMI, trunk lean mass, or trunk fat mass. The magnitude of effect relating TBS and LS-VBMD also decreased with increasing BMI (interaction, p = 0.090) and increasing trunk lean mass (interaction, p = 0.001), but not with increasing trunk fat mass (interaction, p = 0.224). In summary, the strength of the association between TBS and LS-VBMD among older men was variable and dependent on BMI and body composition, particularly trunk lean mass. The clinical utility of TBS among older men may be somewhat limited among men with high BMI or high trunk lean mass. © 2016 American Society for Bone and Mineral Research.

THE MEASUREMENT OF BONE QUALITY USING GRAY LEVEL CO-OCCURRENCE MATRIX TEXTURAL FEATURES

In this paper, statistical methods for the estimation of bone quality to predict the risk of fracture are reported. Bone mineral density and bone architecture properties are the main contributors of bone quality. Dual-energy X-ray Absorptiometry (DXA) is the traditional clinical measurement technique for bone mineral density, but does not include architectural information to enhance the prediction of bone fragility. Other modalities are not practical due to cost and access considerations. This study investigates statistical parameters based on the Gray Level Co-occurrence Matrix (GLCM) extracted from two-dimensional projection images and explores links with architectural properties and bone mechanics. Data analysis was conducted on Micro-CT images of 13 trabecular bones (with an in-plane spatial resolution of about 50μm). Ground truth data for bone volume fraction (BV/TV), bone strength and modulus were available based on complex 3D analysis and mechanical tests. Correlation between the statistical parameters and biomechanical test results was studied using regression analysis. The results showed Cluster-Shade was strongly correlated with the microarchitecture of the trabecular bone and related to mechanical properties. Once the principle thesis of utilizing second-order statistics is established, it can be extended to other modalities, providing cost and convenience advantages for patients and doctors.

Treatment of acromegaly increases BMD but reduces trabecular bone score: a longitudinal study

CONTEXT

Bone turnover is increased in acromegaly. Despite normalization of bone turnover after treatment, the risk for vertebral fractures remains increased. Gonadal status, but not BMD, is correlated with vertebral fractures. Trabecular bone score (TBS) is related to bone microarchitecture.

OBJECTIVE

The aim of this study is to assess the longitudinal change in TBS and BMD following treatment for acromegaly. DESIGN, SETTING, PATIENTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: This longitudinal study included 48 patients with acromegaly between 2005 and 2015. BMD, TBS, and markers for bone turnover (P1NP and CTX-1) were measured at baseline and following treatment.

RESULTS

Following treatment, the mean TBS decreased by 3.0 (±7.0) %, whereas the BMD at the lumbar spine (LS) increased by 3.2 (±4.9) % (both P<0.01). The changes in BMD LS and TBS were not correlated (P=0.87). The TBS change was found to be -4.5 % (±6.7; P=0.003) in men and -0.3 % (±6.8; P=0.85) in women (P=0.063 for interaction men vs women). The mean BMD LS increased in men +4.2 g/cm(2) (±4.3; P<0.001), but not in women +1.5 g/cm(2) (±5.6; P=0.36); (P=0.073 for interaction). BMD increased in the ultradistal radius and total body (both P<0.01). The increase in BMD LS was associated with a decrease in P1NP and CTX-1 (P<0.001) and with lower P1NP and CTX-1 at the follow-up (P<0.02).

CONCLUSION

Treatment of acromegaly affects TBS and BMD at LS in different manners. The reduction of bone turnover markers predicts the increase in BMD but not the decrease in TBS. The DXA changes were more pronounced in men. Alterations in trabecular bone architecture may explain the persistent fracture risk despite the increase in BMD after disease control.

Trabecular bone scores and lumbar spine bone mineral density of US adults: comparison of relationships with demographic and body size variables

This study examines demographic patterns and body size relationships in trabecular bone score and lumbar spine BMD of US adults from NHANES 2005-2008.

INTRODUCTION

Limited data exist on demographic and body size relationships for trabecular bone score (TBS), a new variable derived from bone texture analysis of lumbar spine dual-energy X-ray absorptiometry (DXA) scans. This study compares demographic patterns and correlations with body size (body mass index (BMI), weight, waist circumference, total body fat, trunk fat, trunk lean) between TBS and lumbar spine bone mineral density (LSBMD) for adults age ≥20 years from the National Health and Nutrition Examination Survey (NHANES) 2005-2008 with BMI in the optimal range for TBS (15-37 kg/m(2)).

METHODS

LSBMD, TBS, body fat, and lean were obtained by DXA. Weight, height, and waist circumference were measured. BMI was calculated from height and weight.

RESULTS

Sex differences in TBS varied by age and race/ethnicity (p sex X age interaction and p sex X race/ethnicity interaction < 0.001). In most of the nine demographic subgroups examined, TBS did not differ by sex (four subgroups) or was significantly higher in women (three subgroups). TBS differences by race/ethnicity were inconsistent in men; in women, non-Hispanic whites (NHWs) had higher TBS than non-Hispanic blacks (NHBs) or Mexican Americans (MAs) in all age groups. In contrast, LSBMD was either significantly higher in men (five subgroups) or did not differ by sex (four subgroups). Race/ethnic differences in LSBMD were consistent across age and sex (NHB > NHW > MA). All body size variables were negatively related to TBS but positively related to LSBMD.

CONCLUSIONS

Demographic patterns and body size relationships differed between TBS and LSBMD.

Osteoporosis Imaging in the Geriatric Patient

Given the expected rapid growth of the geriatric world population (=individuals aged >65 years) to 1.3 billion by 2050, age-related diseases such as osteoporosis and its sequelae, osteoporotic fractures, are on the rise. Areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) is the current gold standard to diagnose osteoporosis, to assess osteoporotic fracture risk, and to monitor treatment-induced BMD changes. However, most fragility fractures occur in patients with normal or osteopenic aBMD, indicating that factors beyond BMD impact bone strength. Recent developments in DXA technology such as TBS, VFA, and hip geometry analysis are now available to assess some of these non-BMD parameters from the DXA image. This review will discuss the use of DXA and DXA-assisted technologies and their respective advantages and disadvantages. Special attention is given to if and how each method is indicated in the geriatric population, and the latest ISCD 2015 guidelines have been incorporated.

Predictors of trabecular bone score in school children

Trabecular bone score (TBS) is a DXA-based tool that assesses bone texture and reflects microarchitecture. It has been shown to independently predict the risk of osteoporotic fracture in the elderly. In this study, we investigated the determinants of TBS in adolescents.

INTRODUCTION

TBS is a gray-level textural measurement derived from lumbar spine DXA images. It appears to be an index of bone microarchitecture that provides skeletal information additional to the standard BMD measurement and clinical risk factors. Our objectives were to characterize the relationship between TBS and both age and pubertal stages and identify other predictors in adolescents.

METHODS

We assessed TBS by reanalyzing spine DXA scan images obtained from 170 boys and 168 girls, age range 10-17 years, gathered at study entry and at 1 year, using TBS software. The results are from post hoc analyses obtained using data gathered from a prospective randomized vitamin D trial. Predictors of TBS were assessed using t test or Pearson's correlation and adjusted using regression analyses, as applicable.

RESULTS

The mean age of the study population was 13.2 ± 2.1 years, similar between boys and girls. Age, height, weight, sun exposure, spine BMC and BMD, body BMC and BMD, and lean and fat mass are all significantly correlated with TBS at baseline (r = 0.20-0.75, p < 0.035). Correlations mostly noted in late-pubertal stages. However, after adjustment for BMC, age remained an independent predictor only in girls.

CONCLUSIONS

In univariate exploratory analyses, age and pubertal stages were determinants of TBS in adolescents. Studies to investigate predictors of TBS and to investigate its value as a prognostic tool of bone fragility in the pediatric population are needed.

Epidemiology of Vertebral Fractures

Vertebral fractures are one of the most common fractures associated with skeletal fragility and can cause as much morbidity as hip fractures. However, the epidemiology of vertebral fractures differs from that of osteoporotic fractures at other skeletal sites in important ways, largely because only one quarter to one-third of vertebral fractures are recognized clinically at the time of their occurrence and otherwise require lateral spine imaging to be recognized. This article first reviews the prevalence and incidence of clinical and radiographic vertebral fractures in populations across the globe and secular trends in the incidence of vertebral fracture over time. Next, associations of vertebral fractures with measures of bone mineral density and bone microarchitecture are reviewed followed by associations of vertebral fracture with various textural measures of trabecular bone, including trabecular bone score. Finally, the article reviews clinical risk factors for vertebral fracture and the association of vertebral fractures with morbidity, mortality, and other subsequent adverse health outcomes.

Association between trabecular bone score and risk factors for fractures in Korean female patients with rheumatoid arthritis

OBJECTIVE

To identify the association between trabecular bone score (TBS) and other known risk factors for fractures in rheumatoid arthritis (RA) patients.

METHODS

One hundred female RA patients aged ≥50 years were enrolled. The following risk factors for fracture were selected: prevalent vertebral fracture (VF), bone mineral density (BMD), TBS, and 10-year probability of major osteoporotic fracture by FRAX® (MOF-FRAX scores). The associations between risk factors were identified, and accuracy of TBS, BMD, and FRAX scores to detect the prevalent VF, the strongest risk factor for future fracture, were assessed.

RESULTS

Twenty-six patients were revealed to have moderate to severe VFs. There was a modest negative correlation between MOF-FRAX score and TBS (r =  -0.367, p < 0.01), while there was no correlation between MOF-FRAX score and L-spine BMD (r =  -0.050, p = 0.62). The areas under curves (AUCs) were 0.818, 0.683, and 0.518 for the MOF-FRAX score, TBS, and L-spine BMD, respectively. Among patients with glucocorticoids (GC) use (n = 57), AUCs were 0.762, 0.758, and 0.448 for their MOF-FRAX score, TBS, and L-spine BMD, respectively.

CONCLUSIONS

TBS showed better correlation with MOF-FRAX score than BMD, and it was superior to BMD in identifying prevalent VFs in RA patients, especially who are in use of GCs.

TBS reflects trabecular microarchitecture in premenopausal women and men with idiopathic osteoporosis and low-traumatic fractures

Transiliac bone biopsies, while widely considered to be the standard for the analysis of bone microstructure, are typically restricted to specialized centers. The benefit of Trabecular Bone Score (TBS) in addition to areal bone mineral density (aBMD) for fracture risk assessment has been documented in cross-sectional and prospective studies. The aim of this study was to test if TBS may be useful as a surrogate to histomorphometric trabecular parameters of transiliac bone biopsies. Transiliac bone biopsies from 80 female patients (median age 39.9 years-interquartile range, IQR 34.7; 44.3) and 43 male patients (median age 42.7 years-IQR 38.9; 49.0) with idiopathic osteoporosis and low traumatic fractures were included. Micro-computed tomography values of bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), structural model index (SMI) as well as serum bone turnover markers (BTMs) sclerostin, intact N-terminal type 1 procollagen propeptide (P1NP) and cross-linked C-telopeptide (CTX) were investigated. TBS values were higher in females (1.282 vs 1.169, p< 0.0001) with no differences in spine aBMD, whereas sclerostin levels (45.5 vs 33.4 pmol/L) and aBMD values at the total hip (0.989 vs 0.971 g/cm(2), p<0.001 for all) were higher in males. Multiple regression models including: gender, aBMD and BTMs revealed TBS as an independent, discriminative variable with adjusted multiple R(2) values of 69.1% for SMI, 79.5% for Tb.N, 68.4% for Tb.Sp, and 83.3% for BV/TV. In univariate regression models, BTMs showed statistically significant results, whereas in the multiple models only P1NP and CTX were significant for Tb.N. TBS is a practical, non-invasive, surrogate technique for the assessment of cancellous bone microarchitecture and should be implemented as an additional tool for the determination of trabecular bone properties.

Spinal Bone Texture Assessed by Trabecular Bone Score in Adolescent Girls With Anorexia Nervosa

CONTEXT

Trabecular bone score (TBS) is a bone assessment tool that offers information beyond that afforded by dual-energy x-ray absorptiometry (DXA) bone mineral density (BMD) measurements. Adolescents with anorexia nervosa (AN) are known to exhibit compromised bone density and skeletal strength.

OBJECTIVES

This study aimed to determine TBS among adolescents with AN and evaluate the correlation with anthropometric, clinical and densitometric variables.

DESIGN

Areal BMD spinal measures were analyzed for TBS. Findings were compared with clinical (height, weight, body mass index [BMI], age, pubertal development, 25-hydroxyvitamin D) and self-reported data (illness duration, amenorrhea, exercise, fracture, family history of osteoporosis, and antidepressant use), and BMD measures by DXA and peripheral quantitative computed tomography (pQCT).

SETTING AND PARTICIPANTS

This was an urban adolescent program consisting of 57 females with AN, age 11-18 y.

INTERVENTIONS

Interventions included DXA (absolute BMD and Z-score), pQCT (volumetric BMD [vBMD] and stress-strain index [SSI]), laboratory evaluation, and questionnaire administration.

MAIN OUTCOME MEASURES

Main outcome measures included TBS, areal and vBMD, SSI, fracture history, disease duration.

RESULTS

The TBS of six participants (11%) showed degraded and 19 (33%) partially degraded microarchitecture. Spinal TBS was correlated (P < .05) with age, height, weight, BMI, pubertal stage, BMD, and body composition by DXA, and BMD and SSI by pQCT. TBS was not correlated with disease duration, fracture, vitamin D status, race, or ethnicity, and self-reported health data.

CONCLUSIONS

TBS showed evidence of degraded microarchitecture in over 40% of this study sample, and strongly correlated with anthropometric data and measures of BMD and skeletal strength. TBS is a novel tool that captures another dimension of bone health in adolescents with AN.

Choosing the tool for osteoporosis risk prediction

PURPOSE OF REVIEW

Predicting fracture risk is a major challenge because it allows the prevention of major osteoporotic fracture in high-risk populations. With the aging of the population, this matter will become of even greater importance. In recent years, novel clinical, biochemical, and imaging tools have been developed to improve the assessment of fracture risk.

RECENT FINDINGS

The present review summarizes novel clinical strategies, Dual energy X-ray absorptiometry (DXA)-derived tools, imaging techniques, and biochemical markers that have been developed recently to improve fracture risk prediction.

SUMMARY

DXA and clinical fracture risk prediction tools are preferential markers of fracture risk. Clinical fracture risk alone might be used if DXA facilities are unavailable. The fracture risk assessment tool may be used in osteoporosis consultation in many countries. Other tools may be used soon after more studies are performed, particularly trabecular bone score, quantitative ultrasound, bone turnover markers. Specific factors for example falls, hip axis length, vertebral fracture assessment could be used in individual patients. This may significantly improve the clinical decision-making.

Trabecular bone score (TBS) as a new complementary approach for osteoporosis evaluation in clinical practice

Trabecular bone score (TBS) is a recently-developed analytical tool that performs novel grey-level texture measurements on lumbar spine dual X-ray absorptiometry (DXA) images, and thereby captures information relating to trabecular microarchitecture. In order for TBS to usefully add to bone mineral density (BMD) and clinical risk factors in osteoporosis risk stratification, it must be independently associated with fracture risk, readily obtainable, and ideally, present a risk which is amenable to osteoporosis treatment. This paper summarizes a review of the scientific literature performed by a Working Group of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis. Low TBS is consistently associated with an increase in both prevalent and incident fractures that is partly independent of both clinical risk factors and areal BMD (aBMD) at the lumbar spine and proximal femur. More recently, TBS has been shown to have predictive value for fracture independent of fracture probabilities using the FRAX® algorithm. Although TBS changes with osteoporosis treatment, the magnitude is less than that of aBMD of the spine, and it is not clear how change in TBS relates to fracture risk reduction. TBS may also have a role in the assessment of fracture risk in some causes of secondary osteoporosis (e.g., diabetes, hyperparathyroidism and glucocorticoid-induced osteoporosis). In conclusion, there is a role for TBS in fracture risk assessment in combination with both aBMD and FRAX.

Fracture Risk Prediction by Non-BMD DXA Measures: the 2015 ISCD Official Positions Part 2: Trabecular Bone Score

Bone mineral density (BMD) as measured by dual-energy X-ray absorptiometry (DXA) is the gold standard for the diagnosis and management of osteoporosis. However, BMD explains only 60%-80% of bone strength, and a number of skeletal features other than BMD contribute to bone strength and fracture risk. Advanced imaging modalities can assess some of these skeletal features, but compared to standard DXA, these techniques have higher costs and limited accessibility. A major challenge, therefore, has been to incorporate in clinical practice a readily available, noninvasive technology that permits improvement in fracture-risk prediction beyond that provided by the combination of standard DXA measurements and clinical risk factors. To this end, trabecular bone score (TBS), a gray-level textural index derived from the lumbar spine DXA image, has been investigated. The purpose of this International Society for Clinical Densitometry task force was to review the evidence and develop recommendations on how to incorporate TBS in clinical practice. Clinical applications of TBS for fracture risk assessment, treatment initiation, monitoring of treatment, and use of TBS in special conditions related to greater fracture risk, were addressed. We present the official positions approved by an expert panel following careful review of the recommendations and evidence presented by the TBS task force.

Random field assessment of inhomogeneous bone mineral density from DXA scans can enhance the differentiation between postmenopausal women with and without hip fractures

Bone mineral density (BMD) measurements from Dual-energy X-ray Absorptiometry (DXA) alone cannot account for all factors associated with the risk of hip fractures. For example, the inhomogeneity of bone mineral density in the hip region also contributes to bone strength. In the stochastic assessment of bone inhomogeneity, the BMD map in the hip region is considered as a random field and stochastic predictors can be calculated by fitting a theoretical model onto the experimental variogram of the BMD map. The objective of this study was to compare the ability of bone mineral density and stochastic assessment of inhomogeneous distribution of bone mineral density in predicting hip fractures for postmenopausal women. DXA scans in the hip region were obtained from postmenopausal women with hip fractures (N=47, Age: 71.3±11.4 years) and without hip fractures (N=45, Age: 66.7±11.4 years). Comparison of BMD measurements and stochastic predictors in assessing bone fragility was based on the area under the receiver operating characteristic curves (AUC) from logistic regression analyses. Although stochastic predictors offered higher accuracy (AUC=0.675) in predicting the risk of hip fractures than BMD measurements (AUC=0.625), this difference was not statistically significant (p=0.548). Nevertheless, the combination of stochastic predictors and BMD measurements had significantly (p=0.039) higher prediction accuracy (AUC=0.748) than BMD measurements alone. This study demonstrates that stochastic assessment of bone mineral distribution from DXA scans can serve as a valuable tool in enhancing the prediction of hip fractures for postmenopausal women in addition to BMD measurements.

Utility of the trabecular bone score (TBS) in secondary osteoporosis

Altered bone micro-architecture is an important factor in accounting for fragility fractures. Until recently, it has not been possible to gain information about skeletal microstructure in a way that is clinically feasible. Bone biopsy is essentially a research tool. High-resolution peripheral Quantitative Computed Tomography, while non-invasive, is available only sparsely throughout the world. The trabecular bone score (TBS) is an imaging technology adapted directly from the Dual Energy X-Ray Absorptiometry (DXA) image of the lumbar spine. Thus, it is potentially readily and widely available. In recent years, a large number of studies have demonstrated that TBS is significantly associated with direct measurements of bone micro-architecture, predicts current and future fragility fractures in primary osteoporosis, and may be a useful adjunct to BMD for fracture detection and prediction. In this review, we summarize its potential utility in secondary causes of osteoporosis. In some situations, like glucocorticoid-induced osteoporosis and in diabetes mellitus, the TBS appears to out-perform DXA. It also has apparent value in numerous other disorders associated with diminished bone health, including primary hyperparathyroidism, androgen-deficiency, hormone-receptor positive breast cancer treatment, chronic kidney disease, hemochromatosis, and autoimmune disorders like rheumatoid arthritis. Further research is both needed and warranted to more clearly establish the role of TBS in these and other disorders that adversely affect bone.

Management of postmenopausal osteoporosis

A hallmark of menopause, which follows the decline in the ovarian production of estrogen, is the aggressive and persistent loss of bone mineral and structural elements leading to loss of bone strength and increased fracture risk. This review focuses on newer methods of diagnosing osteoporosis and assessing fracture risk, as well as on novel management strategies for prevention and treatment. Fracture-risk prediction has been significantly enhanced by the development of methods such as the trabecular bone score, which helps assess bone microarchitecture and adds value to standard bone densitometry, and the Fracture Risk Assessment Tool (FRAX) algorithm techniques. The treatment of osteoporosis, which has the goals of fracture prevention and risk reduction, is moving beyond traditional monotherapies with antiresorptives and anabolic agents into new combination regimens.

Spine bone texture assessed by trabecular bone score (TBS) predicts osteoporotic fractures in men: the Manitoba Bone Density Program

INTRODUCTION

One quarter of osteoporotic fractures occur in men. TBS, a gray-level measurement derived from lumbar spine DXA image texture, is related to microarchitecture and fracture risk independently of BMD. Previous studies reported the ability of spine TBS to predict osteoporotic fractures in women. Our aim was to evaluate the ability of TBS to predict clinical osteoporotic fractures in men.

METHODS

3620 men aged ≥50 (mean 67.6years) at the time of baseline DXA (femoral neck, spine) were identified from a database (Province of Manitoba, Canada). Health service records were assessed for the presence of non-traumatic osteoporotic fracture after BMD testing. Lumbar spine TBS was derived from spine DXA blinded to clinical parameters and outcomes. We used Cox proportional hazard regression to analyze time to first fracture adjusted for clinical risk factors (FRAX without BMD), osteoporosis treatment and BMD (hip or spine).

RESULTS

Mean followup was 4.5years. 183 (5.1%) men sustain major osteoporotic fractures (MOF), 91 (2.5%) clinical vertebral fractures (CVF), and 46 (1.3%) hip fractures (HF). Correlation between spine BMD and spine TBS was modest (r=0.31), less than correlation between spine and hip BMD (r=0.63). Significantly lower spine TBS were found in fracture versus non-fracture men for MOF (p<0.001), HF (p<0.001) and CVF (p=0.003). Area under the receiver operating characteristic curve (AUC) for incident fracture discrimination with TBS was significantly better than chance (MOF AUC=0.59, p<0.001; HF AUC=0.67, p<0.001; CVF AUC=0.57, p=0.032). TBS predicted MOF and HF (but not CVF) in models adjusted for FRAX without BMD and osteoporosis treatment. TBS remained a predictor of HF (but not MOF) after further adjustment for hip BMD or spine BMD.

CONCLUSION

We observed that spine TBS predicted MOF and HF independently of the clinical FRAX score, HF independently of FRAX and BMD in men. Studies with more incident fractures are needed to confirm these findings.

Comparing bone microarchitecture by trabecular bone score (TBS) in Caucasian American women with and without osteoporotic fractures

Several cross-sectional studies have shown the ability of the TBS to discriminate between those with and without fractures in European populations. The aim of this study was to assess the ability of TBS to discriminate between those with and without fractures in a large female Caucasian population in the USA. This was a case-control study of 2,165 Caucasian American women aged 40 and older. Patients with illness or taking medications known to affect bone metabolism were excluded. Those in the fracture group (n = 289) had at least one low-energy fracture. BMD was measured at L1-L4, TBS calculated directly from the same DXA image. Descriptive statistics and inferential tests for difference were used. Univariate and multivariate logistic regression models were created to investigate possible association between independent variables and the status of fracture. Odds ratios per standard deviation decrease (OR) and areas under the ROC curve were calculated for discriminating parameters. Weak correlations were observed between TBS and BMD and between TBS and BMI (r = 0.33 and -0.17, respectively, p < 0.01). Mean age, weight, BMD and TBS were significantly different between control and fracture groups (all p ≤ 0.05), whereas no difference was noted for BMI or height. After adjusting for age, weight, BMD, smoking, and maternal and family history of fracture, TBS (but not BMD) remained a significant predictor of fracture: OR 1.28[1.13-1.46] even after adjustment. In a US female population, TBS again was able to discriminate between those with and those without fractures, even after adjusting for other clinical risk factors.

Trabecular bone score: perspectives of an imaging technology coming of age

The trabecular bone score (TBS) is a new method to describe skeletal microarchitecture from the dual energy X-ray absorptiometry (DXA) image of the lumbar spine. While TBS is not a direct physical measurement of trabecular microarchitecture, it correlates with micro-computed tomography (µCT) measures of bone volume fraction, connectivity density, trabecular number, and trabecular separation, and with vertebral mechanical behavior in ex vivo studies. In human subjects, TBS has been shown to be associated with trabecular microarchitecture and bone strength by high resolution peripheral quantitative computed tomography (HRpQCT). Cross-sectional and prospective studies, involving a large number of subjects, have both shown that TBS is associated with vertebral, femoral neck, and other types of osteoporotic fractures in postmenopausal women. Data in men, while much less extensive, show similar findings. TBS is also associated with fragility fractures in subjects with secondary causes of osteoporosis, and preliminary data suggest that TBS might improve fracture prediction when incorporated in the fracture risk assessment system known as FRAX. In this article, we review recent advances that have helped to establish this new imaging technology.