African Americans have lower TBS than whites among densitometry patients at a Chicago academic center

Bridging Genomic Research Disparities in Osteoporosis GWAS: Insights for Diverse Populations

PURPOSE OF REVIEW

Genome-wide association studies (GWAS) have significantly advanced osteoporosis research by identifying genetic loci associated with bone mineral density (BMD) and fracture risk. However, disparities persist due to the underrepresentation of non-European populations, limiting the applicability of polygenic risk scores (PRS). This review examines recent advancements in osteoporosis genetics, highlights existing disparities, and explores strategies for more inclusive research.

RECENT FINDINGS

European-focused GWAS have identified key loci for osteoporosis, including WNT signaling (SOST, LRP5) and RUNX2 transcriptional regulation. However, fewer than 40% of these variants can be replicated in Asian and African populations. Emerging studies in non-European groups reveal population-specific loci, sex-specific associations, and gene-environment interactions. Advances in machine learning (ML)-assisted GWAS and multi-omics integration are improving genetic discovery. Expanding GWAS in diverse populations, integrating multi-omics data, refining ML-based risk models, and standardizing biobank data are essential for equitable osteoporosis research. Future efforts must prioritize clinical translation to enhance personalized osteoporosis prevention and treatment.

Bone Structural Parameters as Measured by 3-Dimensional Dual-Energy X-Ray Absorptiometry Are Superior in Black Women and Demonstrate Unique Associations With Prior Fracture Versus White Women

OBJECTIVE

Black patients fracture less often than White patients at any given bone mineral density (BMD). This may be related to superior bone structure; however, bone structure is challenging to measure in clinical practice. Advances in 3-dimensional (3D) modeling have allowed for the measurement of trabecular and cortical parameters from dual-energy x-ray absorptiometry (DXA). This technology, known as 3D-DXA, may provide a way to assess hitherto unexplained differences in bone structure between Black and White patients.

METHODS

This is a secondary analysis of 775 women (368 Black and 407 White) previously recruited from an osteoporosis clinic. All women had undergone DXA and vertebral fracture assessment, and 3D-DXA was run retrospectively on the proximal femur BMD scan. Participants were classified as having a prior fracture if there was a fracture on vertebral fracture assessment or a self-reported history of fragility fracture.

RESULTS

Black women had generally superior 3D-DXA parameters, with the largest differences in cortical thickness of the femoral neck (FN) and buckling ratio of the FN. There were substantial differences in associations between fracture and 3D-DXA parameters in Black women compared with White women. After adjusting for age, glucocorticoids, and areal BMD T-score, cortical thickness of the FN was significantly associated with prior fracture (odds ratio, 1.4 per standard deviation decline; 95% CI, 1.0-1.9; P = .04) in Black women but not White women.

CONCLUSION

3D-DXA parameters were superior in Black women than in White women, and cortical thickness of the FN was associated with fractures only in Black women. 3D-DXA may improve fracture risk assessment in Black patients.

Clinical Use of Trabecular Bone Score: The 2023 ISCD Official Positions

Osteoporosis can currently be diagnosed by applying the WHO classification to bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry (DXA). However, skeletal factors other than BMD contribute to bone strength and fracture risk. Lumbar spine TBS, a grey-level texture measure which is derived from DXA images has been extensively studied, enhances fracture prediction independent of BMD and can be used to adjust fracture probability from FRAX® to improve risk stratification. The purpose of this International Society for Clinical Densitometry task force was to review the existing evidence and develop recommendations to assist clinicians regarding when and how to perform, report and utilize TBS. Our review concluded that TBS is most likely to alter clinical management in patients aged ≥ 40 years who are close to the pharmacologic intervention threshold by FRAX. The TBS value from L1-L4 vertebral levels, without vertebral exclusions, should be used to calculate adjusted FRAX probabilities. L1-L4 vertebral levels can be used in the presence of degenerative changes and lumbar compression fractures. It is recommended not to report TBS if extreme structural or pathological artifacts are present. Monitoring and reporting TBS change is unlikely to be helpful with the current version of the TBS algorithm. The next version of TBS software will include an adjustment based upon directly measured tissue thickness. This is expected to improve performance and address some of the technical factors that affect the current algorithm which may require modifications to these Official Positions as experience is acquired with this new algorithm.

Osteoporosis and Fracture Risk among Older US Asian Adults

PURPOSE OF REVIEW

This review summarizes the current knowledge regarding osteoporosis and fracture among older US Asian adults.

RECENT FINDINGS

Asian adults have lower (areal) bone density than non-Hispanic White adults and thus are more likely to be diagnosed and treated for osteoporosis, despite their lower risk of hip fracture. The latter may relate to favorable characteristics in hip geometry, volumetric bone density, and bone microarchitecture; lower risk of falls; and other clinical factors. The fracture risk calculator FRAX accounts for the lower risk of hip fracture among US Asian adults. However, data on major osteoporotic fracture risk remain limited. Fracture rates also vary by Asian subgroup, which may have implications for fracture risk assessment. Furthermore, among women receiving bisphosphonate drugs, Asian race is a risk factor for atypical femur fracture, an uncommon complication associated with treatment duration. Recent clinical trial efficacy data pertaining to lower bisphosphonate doses and longer dosing intervals may be relevant for Asian adults. More research is needed to inform osteoporosis care of US Asian adults, including risk-benefit considerations and the optimal duration of bisphosphonate treatment. Greater evidence-based guidance for primary fracture prevention among US Asian adults will ensure health equity in the prevention of osteoporotic fractures.

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

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

Race/ethnic difference in trabecular bone score in midlife women: The Study of Women's Health Across the Nation (SWAN)

There was no difference in Trabecular Bone Score (TBS) comparing White and Black women after adjusting for body mass index (BMI) and diabetes status. Japanese women had lower TBS than White women. Our results diverge from established differences in fracture rates by race/ethnicity.

INTRODUCTION

The TBS was developed as an indirect measure of vertebral bone microarchitecture derived from texture analysis of lumbar spine DXA scans. There is little information on race/ethnic differences in TBS.

METHODS

We compared TBS in 656 White, 492 Black, and 268 Japanese pre- and early perimenopausal women. We used a beta version of TBS that accounts for tissue thickness using DXA measured soft tissue thickness rather than BMI. The relation between BMI and tissue thickness corrected TBS differed by BMI; we used a three-segment linear spline to adjust for BMI.

RESULTS

The women were, on average, 46.5 years of age; 50% were premenopausal. In BMI and diabetes adjusted models, there was no difference in TBS between White and Black women. TBS was modestly (2%) lower in the Japanese women compared to White women, p = 0.04. In a sensitivity analysis, restricting the analysis to those with BMI 24-31 kg/m², results were similar.

CONCLUSIONS

TBS was similar in Black and White women after accounting for tissue thickness and adjusting for BMI, diabetes, and other covariates. The Japanese women had modestly lower TBS. These results diverge from established race/ethnic differences in fracture rates and areal bone mineral density, underscoring the need for further studies.

Trabecular bone score of postmenopausal women is positively correlated with bone mineral density and negatively correlated with age and body mass index

OBJECTIVE

Trabecular bone score (TBS), an indirect evaluation of skeletal microarchitecture, is calculated from dual-energy X-ray absorptiometry (DXA). This study aimed to determine the mean TBS values in healthy postmenopausal women and overall association between TBS and demographic features, bone mineral density (BMD) of the lumbar spine and femoral neck, and BMD to body mass index (BMI) ratio of the lumbar spine.

METHODS

Fifty-three postmenopausal healthy women were enrolled. The BMD of the lumbar spine and femoral neck was measured by DXA. Anteroposterior lumbar spine acquisitions were used to calculate the TBS for L1 to L4.

RESULTS

The mean BMD of the lumbar spine and femoral neck was 0.945 ± 0.133 and 0.785 ± 0.112 g/cm, respectively. The mean TBS was 1.354 ± 0.107. There was a significant positive moderate correlation between TBS and total lumbar BMD to BMI ratio (r = 0.595, P < 0.001), and significant positive weak correlations between TBS and BMD of the lumbar spine (r = 0.347, P = 0.011) as well as between TBS and femoral neck (r = 0.305, P = 0.026), whereas significant negative moderate correlations were observed between TBS and age (r = -0.393, P = 0.004) as well as between TBS and BMI (r = -0.333, P = 0.015).

CONCLUSIONS

TBS values of postmenopausal women were negatively correlated with age and BMI, and positively with BMD and BMD to BMI ratio.

The utility and limitations of using trabecular bone score with FRAX

PURPOSE OF REVIEW

Trabecular bone score (TBS) is a texture index derived from the lumbar spine dual-energy X-ray absorptiometry which can assess skeletal quality and provide information about fracture risk independent of bone mineral density (BMD). TBS is useful in assessing osteoporotic fracture risk, with lower TBS values associated with increased fracture risk. In this article, we review the current state of TBS, including its utility and limitations in the assessment and management of osteoporosis, with particular emphasis on the recent literature.

RECENT FINDINGS

Ten-year fracture risk assessment using the FRAX tool can be improved through the use of a TBS adjustment. The use of TBS-adjusted FRAX can change management in a modest but significant number of patients, particularly in those close to an intervention threshold. Change in lumbar spine TBS for patients undergoing antiresorptive treatment is not a useful indicator of antifracture effect.

SUMMARY

Lumbar spine TBS provides information complementary to conventional BMD, and has been shown to be clinically useful for enhancing fracture risk prediction.

Physical activity as measured by accelerometer in NHANES 2005-2006 is associated with better bone density and trabecular bone score in older adults

In an analysis of NHANES 2005-2006, older, but not younger, women and men with higher levels of physical activity had higher TBS, total hip T-score, and femoral neck T-score. Even modest levels of physical activity may be a crucial component of bone health maintenance.

PURPOSE

Physical activity is associated with improved bone parameters in adolescence, but it is not clear if this persists into adulthood. Further, it is unclear how low levels of physical activity as measured by accelerometer may impact bone parameters.

METHODS

We analyzed data from subjects from NHANES 2005-2006 over the age of 20 who had accelerometry and bone mineral density (BMD) testing. We analyzed women and men separately and grouped by over or under 50 years of age: 484 younger women, 486 older women, 604 younger men, and 609 older men. Moderate-to-vigorous physical activity (MVPA) was categorized as low (less than 5 min daily), intermediate (5-20 min daily), or high (at least 20 min daily).

RESULTS

Among younger women and men, there was no significant relationship between MVPA and BMD or trabecular bone score (TBS). Conversely, older women with intermediate and high MVPA had higher TBS (1.360 ± 0.008 and 1.377 ± 0.009 vs 1.298 ± 0.010, p < 0.001), total hip T-score (- 1.02 ± 0.13 and - 0.90 ± 0.09 vs. - 1.51 ± 0.08, p < 0.01), and femoral neck T-score than women with low MVPA, respectively. Similarly, older men with high MVPA had higher TBS, total hip T-score, and femoral neck T-score than men with intermediate and low MVPA.

CONCLUSIONS

Older, but not younger, women and men with higher levels of activity had higher BMD and TBS. Benefits were noted with as little as 5-20 min of daily physical activity. Our results suggest that physical activity is a crucial component of bone health maintenance.

The trabecular bone score: Relationships with trabecular and cortical microarchitecture measured by HR-pQCT and histomorphometry in patients with chronic kidney disease

The trabecular bone score (TBS) is a novel tool using grayscale variograms of the lumbar spine bone mineral density (BMD) to assess trabecular bone microarchitecture. Studies in patients with chronic kidney disease (CKD) suggest it may be helpful in assessing fracture risk. However, TBS has not been validated as a measure of trabecular architecture against transiliac bone biopsy with histomorphometry in CKD patients. We hypothesized that TBS would reflect trabecular architecture at the iliac crest in CKD patients. We obtained tetracycline double labeled transiliac crest bone biopsy, areal BMD of the spine, total hip, femoral neck (FN) and spine TBS by dual energy X-ray absorptiometry (DXA), and cortical and trabecular volumetric density and microarchitecture by high resolution peripheral quantitative computed tomography (HR-pQCT) in CKD patients from two centers: twenty-two patients from Columbia University Medical Center, USA and thirty patients from Hospital das Clinicas - Universidade de São Paulo, Brazil. Two patients were excluded for outlier status. Univariate and multivariate relationships between TBS and measures from DXA, HR-pQCT and histomorphometry were determined. Patients were 50.2 ± 15.8 years old, 23 (46%) were men, and 33 (66%) were on dialysis. TBS was <1.31 in 21 (42%) patients and 22%, 14% and 10% had T-scores ≤ -2.5 at spine, FN and total hip respectively. In univariate regression, TBS was significantly associated with trabecular bone volume (BV/TV), trabecular width (Tb.Wi), trabecular spacing, cortical width but not with trabecular number or cortical porosity. FN Z-score and height were also associated with cancellous BV/TV and Tb.Wi, In multivariate analysis, TBS remained an independent predictor of BV/TV and Tb.Wi. There were no relationships between TBS and dynamic parameters from histomorphometry. These data suggest that TBS reflected trabecular microarchitecture and cortical width measured by bone biopsy in CKD patients. Future studies should address its utility in the identification of CKD patients who may benefit from fracture prevention strategies.

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.

Association of trabecular bone score (TBS) and prior fracture differs among minorities in NHANES 2005-2008

The study investigates the association of trabecular bone score (TBS) and fractures among minority populations. In NHANES 2005-2008, TBS was associated with history of fractures in Caucasian subjects but demonstrated somewhat weaker associations in African American and Mexican American women.

INTRODUCTION

Trabecular bone score (TBS), a textural analysis of the lumbar spine DXA image, predicts fractures well in Caucasian (CA) and Asian populations but is less well studied in African American (AA) and Mexican American (MA) subjects. It is not clear whether TBS is associated with or is predictive of fragility in these racial/ethnic groups.

METHODS

We analyzed data from subjects from NHANES 2005-2008 over the age of 40 who had TBS: 1178 CA, 467 AA, and 397 MA women and 1200 CA, 502 AA, and 386 MA men. TBS was categorized into normal, ≥ 1.310, partially degraded < 1.310, and > 1.230, or degraded, ≤ 1.230. History of fracture was assessed by questionnaire.

RESULTS

Among women, there was an increasing prevalence of fracture with worsening TBS category. However, when controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA women (OR 1.49 per worsening category, 95% CI 1.20-1.85). In men, there was also an increase in the prevalence of fracture with worsening TBS category in all races/ethnicities. When controlling for age, BMI, and low T-score, the association between TBS category and previous fracture was only significant in CA men (OR 1.47 per worsening category, 95% CI 1.10-1.95), though analysis was somewhat limited by small fracture numbers.

CONCLUSIONS

The association of fracture and TBS varies by race/ethnicity and gender with weaker association observed in AA and MA women. More research is needed to define the proper use of TBS for predicting fractures in minority groups.

Trabecular Bone Score Is a Valuable Addition to Bone Mineral Density for Bone Quality Assessment in Older Mexican American Women With Type 2 Diabetes

Altered bone quality due to the underlying metabolic changes of type 2 diabetes (T2D) has been hypothesized to affect bone strength, leading to increased fracture risk in patients with T2D. Lumbar spine trabecular bone score (LS-TBS), an indirect measure of trabecular microarchitecture, provides information on bone quality and has been associated with T2D. However, trabecular bone score (TBS) is also affected by demographic patterns and body size, and is expected to be different in people from various ethnic or racial backgrounds. Therefore, it is important to understand associations between T2D and TBS for each ethnic or racial group separately. Although the relationship between TBS and age has been reported to be similar between non-Hispanic Caucasians and Mexican Americans (MAs), data on associations of LS-TBS with T2D in older MAs are lacking. Here, we report associations between TBS and T2D in 149 older MA men and women. Participants are part of a cohort known as the Cameron County Hispanic Cohort in Texas who have high prevalence of obesity and poor glycemic control. Bone mineral density was not altered for MA women with T2D, but was significantly higher in MA men with T2D compared with MA men without diabetes. Low LS-TBS was associated with T2D in women in our study. Although low TBS was associated with older age in men, TBS did not show any significant association with T2D for men. These results are similar to those found in other studies of non-Hispanic whites with diabetes. LS-TBS may add value in diagnosing poor bone quality in older MA women with T2D regardless of bone mineral density scoring.

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.