Uncovering the obesity paradox: waist-to-height ratio as a marker of vertebral fragility independent of bone mineral density

Chadi Rakieh; Claire Mennan; Jan-Herman Kuiper; Diane Powell; Shu Ho; Muhammad Javaid

doi:10.1530/obabs.08.P68

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Bone Abstracts (2026) 8 P68 | DOI: 10.1530/obabs.08.P68

OP2026 Poster Presentations Original Research (32 abstracts)

Uncovering the obesity paradox: waist-to-height ratio as a marker of vertebral fragility independent of bone mineral density

Chadi Rakieh ¹ , Claire Mennan ¹ , Jan-Herman Kuiper ¹ , Diane Powell ¹ , Shu Ho ¹ & Muhammad Javaid ²

Author affiliations

¹The Robert Jones Agnes Hunt Orthopaedic Hospital NHS Foundation Trust, Oswestry, United Kingdom;²University of Oxford, Oxford, United Kingdom

Background: The relationship between obesity and fracture risk is complex. While higher body mass index (BMI) associates with greater bone mineral density (BMD) and appears protective against hip fractures, clinical observations suggest central adiposity contributes to spinal fragility. We investigated whether waist-to-height ratio (WHtR) is associated with recent vertebral fractures, a relationship often obscured by the obesity paradox inherent in BMI-based assessment.

Methods: We conducted a cross-sectional study of 1,005 adults (postmenopausal women and men aged ≥50) attending a UK bone densitometry service in 2023. Logistic regression estimated associations between BMI or WHtR and recent fractures (within two years), specifically radiologically confirmed vertebral fractures. Models were adjusted for age, sex, and total hip BMD.

Results: Recent fractures occurred in 30.1% of participants; vertebral fractures in 10.8%. BMI correlated more strongly with BMD than WHtR (ρ 0.45 vs 0.28). BMI-defined obesity showed no independent association with vertebral fracture after adjustment, indicating no incremental value beyond BMD. In contrast, high central adiposity (WHtR ≥0.6) remained independently associated with vertebral fracture after adjustment (Table 1).

Table 1. Adjusted odds ratios for recent fracture by obesity measure, with reference categories normal BMI (18.525) and healthy WHtR (0.5).
Obesity measure	Vertebral fracture, adjusted OR (95% CI)	Any fracture, adjusted OR (95% CI)	Hip fracture, adjusted OR (95% CI)
BMI obese (≥30 kg/m²)	1.6 (0.92.8)	1.7 (1.12.4)*	1.2 (0.52.8)
WHtR high (≥0.6)	2.8 (1.36.6)*	2.2 (1.43.6)**	2.6 (0.99.5)
P 0.05; *P ≤0.001. Adjusted for age, sex, and total hip BMD.

Conclusion: BMI and WHtR capture different aspects of adiposity relevant to skeletal health. BMI may obscure vertebral fracture risk due to its strong association with BMD, whereas WHtR identifies central adiposity associated with fracture independent of bone density.