Determinants of trabecular bone score and prevalent vertebral fractures in women with fragility fractures: a cross-sectional sub-study of NoFRACT.

Abstract

Determinants of trabecular bone score (TBS) and vertebral fractures assessed semiquantitatively (SQ1-SQ3) were studied in 496 women with fragility fractures. TBS was associated with age, parental hip fracture, alcohol intake and BMD, not SQ1-SQ3 fractures. SQ1-SQ3 fractures were associated with age, prior fractures, and lumbar spine BMD, but not TBS. Trabecular bone score (TBS) and vertebral fractures assessed by semiquantitative method (SQ1-SQ3) seem to reflect different aspects of bone strength. We therefore sought to explore the determinants of and the associations between TBS and SQ1-SQ3 fractures. This cross-sectional sub-study of the Norwegian Capture the Fracture Initiative included 496 women aged ≥ 50 years with fragility fractures. All responded to a questionnaire about risk factors for fracture, had bone mineral density (BMD) of femoral neck and/or lumbar spine assessed, TBS calculated, and 423 had SQ1-SQ3 fracture assessed. Mean (SD) age was 65.6 years (8.6), mean TBS 1.27 (0.10), and 33.3% exhibited SQ1-SQ3 fractures. In multiple variable analysis, higher age (β_{per SD} = - 0.26, 95% CI: - 0.36,- 0.15), parental hip fracture (β = - 0.29, 95% CI: - 0.54,- 0.05), and daily alcohol intake (β = - 0.43, 95% CI - 0.79, - 0.08) were associated with lower TBS. Higher BMD of femoral neck (β_{per SD} = 0.34, 95% CI 0.25-0.43) and lumbar spine (β_{per SD} = 0.40, 95% CI 0.31-0.48) were associated with higher TBS. In multivariable logistic regression analyses, age (OR_{per SD} = 1.94, 95% CI 1.51-2.46) and prior fragility fractures (OR = 1.71, 95% CI 1.09-2.71) were positively associated with SQ1-SQ3 fractures, while lumbar spine BMD (OR_{per SD} = 0.75 95% CI 0.60-0.95) was negatively associated with SQ1-SQ3 fractures. No association between TBS and SQ1-SQ3 fractures was found. Since TBS and SQ1-SQ3 fractures were not associated, they may act as independent risk factors, justifying the use of both in post-fracture risk assessment.