The Obesity–Bone Paradox in Postmenopausal Women: Divergent Associations of BMI with Bone Mineral Density and Trabecular Bone Score in a Real-World DXA Cohort
Aug 2026· Medicina· Vol 62· 0 citations· 44 references
Medicine
TL;DR
In postmenopausal women, higher BMI was associated with higher BMD but lower TBS, supporting a divergent relationship between densitometric findings and DXA-derived trabecular texture parameters, and suggesting that TBS may complement BMD in describing skeletal imaging status in overweight and obese women.
Abstract
Background and Objectives: Body mass index (BMI) has a complex relationship with skeletal health. Higher BMI is often associated with higher bone mineral density (BMD), but this apparent densitometric advantage may not fully reflect bone microarchitecture. Trabecular bone score (TBS) may provide complementary information in overweight and obese postmenopausal women. This study evaluated the associations between BMI, BMD, and TBS in postmenopausal women and assessed whether increased BMI is associated with discordant skeletal phenotypes characterized by non-osteoporotic densitometric status but impaired trabecular microarchitecture. Materials and Methods: This retrospective observational study screened 110 DXA/TBS reports from patients evaluated in a tertiary DXA center. Inclusion criteria were female sex, postmenopausal status, available BMI or sufficient anthropometric data for BMI calculation, valid lumbar spine DXA, at least one valid hip DXA assessment, and valid lumbar TBS assessment. Four cases were excluded: two male patients and two non-menopausal female patients. The final analytical cohort included 106 postmenopausal women. Lumbar spine and hip BMD, T-scores, TBS, Bone Resilience Index, anthropometric variables, and menopausal variables were extracted from DXA/TBS reports. BMI was analyzed both continuously and by category: under/normal-weight, overweight, and obesity. Correlation analyses, group comparisons, and linear regression models were used to evaluate the relationship between BMI and skeletal parameters. Discordant skeletal phenotypes were defined descriptively as non-osteoporotic DXA findings combined with degraded TBS. Results: The final cohort had a mean age of 65.2 ± 7.6 years and a mean BMI of 27.3 ± 4.5 kg/m2. BMI was positively associated with lumbar spine BMD (r = 0.392, p < 0.001), minimum femoral neck BMD (r = 0.382, p < 0.001), and minimum total hip BMD (r = 0.508, p < 0.001), but negatively associated with TBS (r = −0.307, p = 0.001). Mean TBS decreased across BMI categories, from 1.283 ± 0.084 in the under/normal-weight group to 1.255 ± 0.088 in the overweight group and 1.199 ± 0.109 in the obesity group. In the fully adjusted regression model including BMI, age, years since menopause, lumbar spine BMD, and lowest hip T-score, BMI remained an independent negative predictor of TBS (β = −0.0126, p < 0.001). Discordant skeletal phenotypes combining non-osteoporotic DXA status with degraded TBS were more frequent in patients with obesity. Conclusions: In postmenopausal women, higher BMI was associated with higher BMD but lower TBS, supporting a divergent relationship between densitometric findings and DXA-derived trabecular texture parameters. These findings suggest that TBS may complement BMD in describing skeletal imaging status in overweight and obese women. Because fracture outcomes and complete clinical risk data were not available, the present results should be interpreted as evidence of imaging discordance rather than direct evidence of clinical underdiagnosis or misclassification.
Background
Obesity has been considered protective against osteoporosis due to its association with higher bone mineral density (BMD). However, metabolic dysfunction, particularly insulin resistance (IR), may compromise bone quality even with BMD preserved.
Methods
This retrospective cross-sectional study (n=254) included 153 individuals with severe obesity undergoing bariatric metabolic surgery and 101 age- and sex-matched non-obese controls. BMD and trabecular bone score (TBS) were measured using dualenergy X-ray absorptiometry. A subgroup of participants with obesity was further analyzed to examine associations between IR, assessed using the homeostasis model assessment of insulin resistance (HOMA-IR), and bone parameters.
Results
BMD was significantly higher in the obese group, indicating preserved bone mass in obesity. But the proportions of spine-hip Z-score discordance was significant higher in the obese group (P=0.001). TBS displayed sitespecific findings: TBS at L1 was significantly higher in the obese group (P=0.002), whereas no significant differences were observed at L2-L4. Partially degraded or degraded TBS were higher in the obese group (P=0.021). Among participants with obesity, TBS decreased progressively across HOMA-IR quartiles (P=0.043), whereas BMD remained stable. In multivariable regression, higher HOMA-IR was independently associated with lower TBS (β=-0.0025; 95% confidence interval, -0.0043 to -0.0006; P=0.015), although this association was attenuated by hemoglobin A1c adjustment.
Conclusion
Patients with obesity demonstrated site-specific reductions in trabecular bone quality, particularly in the lower lumbar spine compared with non-obese people. IR was independently and inversely associated with TBS, suggesting that metabolic dysfunction, not mechanical loading, influences bone fragility in obesity. TBS represents a valuable adjunct to BMD for assessing skeletal health in metabolically impaired obese populations.
Taehoon Park, K. Seo, Ki Hyun Kim et al.· Endocrinology and Metabolism· 0 citations
It is indicated that trabecular microarchitecture deteriorates earlier and more rapidly with aging than bone mass loss captured by BMD, supporting the use of TBS as a complementary tool for evaluating skeletal health and fracture risk.
C. Gomes, R. M. R. Pereira, J. C. Alvarenga et al.· Menopause· 0 citations
It is suggested that visceral adiposity measured by opportunistic CT may serve as a potential biomarker for identifying postmenopausal women with osteopenia who are at an increased risk of fracture.
Tae Ran Ahn, Hyun Su Kim, D. Cha et al.· Skeletal Radiology· 0 citations
The trabecular bone score (TBS) provides complementary, indirect information on trabecular microarchitecture that may be independently impaired in SSc, and SSc patients exhibit significantly impaired bone microarchitecture compared with matched controls.
Nipaporn Intarasattakul, C. Pongchaiyakul, C. Foocharoen et al.· Journal of clinical densitom...· 0 citations
Study Design
Retrospective sex- and age-matched case-control study.
Purpose
To assess bone mineral density (BMD)-trabecular bone score (TBS) discordance and high-burden abdominal aortic calcification (AAC) in patients with radiographically confirmed osteoporotic vertebral compression fracture (OVCF).
Overview of Literature
Conventional BMD thresholds may fail to identify all patients with vertebral skeletal fragility, as vertebral fractures can occur despite nonosteoporotic BMD. TBS complements BMD by evaluating trabecular microarchitecture, while AAC may serve as a marker of systemic bone-vascular health associated with skeletal fragility.
Methods
This retrospective sex- and age-matched case-control study enrolled patients aged ≥50 years who underwent dual-energy X-ray absorptiometry (DXA) with TBS assessment and vertebral imaging. OVCF was defined as a Genant grade 2 or 3 vertebral fracture. The primary cohort included 47 OVCF patients and 188 matched controls. BMD T-scores at the lumbar spine, femoral neck, total hip, TBS, and AAC-24 were evaluated. Matched conditional logistic regression was used to determine associations with OVCF.
Results
More than half of OVCF patients did not demonstrate osteoporotic BMD at any measured DXA site (53.2%). Among those with nonosteoporotic BMD, low TBS was more common in cases than in controls (48.0% vs. 22.7%). Low TBS remained independently associated with OVCF after adjusting for the lowest BMD T-score and high-burden AAC (odds ratio, 2.66; 95% confidence interval, 1.25-5.63; p =0.011). High-burden AAC was more frequent among cases, although its association was attenuated after adjustment.
Conclusions
Low TBS may aid in identifying vertebral skeletal fragility in OVCF patients with nonosteoporotic BMD on conventional DXA. High-burden AAC may provide vascular information, although its incremental association beyond BMD and TBS was attenuated.
Highlights What are the main findings? Higher appendicular skeletal muscle mass index was independently associated with higher bone mineral density at the lumbar spine, total hip, and femoral neck. Waist circumference remained independently associated with bone mineral density at the total hip, but not at the lumbar spine or femoral neck, after multivariable adjustment. What are the implications of the main findings? Assessment of muscle mass provides additional information beyond body weight or body mass index when evaluating skeletal health in postmenopausal women. Combining routine waist circumference measurement with bioelectrical impedance analysis-derived muscle assessment may provide complementary information on body composition and skeletal health in outpatient practice. Abstract Background/Objectives: Postmenopausal aging is accompanied by progressive loss of skeletal muscle mass and increased abdominal adiposity, both of which may influence bone health through distinct mechanical and metabolic pathways. However, their independent associations with bone mineral density (BMD) at different skeletal sites remain incompletely characterized. This study investigated the independent associations of appendicular skeletal muscle mass index (ASMI) and waist circumference (WC) with site-specific BMD in postmenopausal women. Methods: This cross-sectional study included 345 postmenopausal women who attended a university hospital menopause clinic in Thailand. Body composition was assessed using multi-frequency bioelectrical impedance analysis, and ASMI was calculated according to the Asian Working Group for Sarcopenia (AWGS) 2019 consensus criteria. WC was measured using standardized anthropometric procedures. BMD at the lumbar spine (L1–L4), total hip, and femoral neck was determined by dual-energy X-ray absorptiometry. Multivariable linear regression analyses were performed to evaluate the independent associations of ASMI and WC with site-specific BMD after adjustment for age, years since menopause, hormone replacement therapy use, osteoporosis medication use, calcium supplementation, vitamin D supplementation, and fracture history. Robust standard errors were used in the final models. Results: Higher ASMI was independently associated with higher BMD at the lumbar spine (standardized β = 0.362, p < 0.001), total hip (standardized β = 0.371, p < 0.001), and femoral neck (standardized β = 0.353, p < 0.001). WC was positively associated with total hip BMD (standardized β = 0.158, p = 0.006), whereas no statistically significant associations were observed at the lumbar spine (standardized β = 0.009, p = 0.899) or femoral neck (standardized β = 0.105, p = 0.092). Conclusions: ASMI was consistently associated with BMD across all measured skeletal sites, whereas the association between WC and BMD varied according to skeletal region. These findings support the complementary assessment of skeletal muscle mass and central adiposity for characterizing body composition and skeletal health in postmenopausal women.
Pattama Tongdee, S. Kupittayanant, Khanidtha Marungrueng et al.· Healthcare· 0 citations
