Fracture risk gradient assessed by categories of bone mineral density and trabecular bone score: the Manitoba BMD Registry.

Abstract

Trabecular bone score (TBS) enhances fracture risk prediction independent of bone mineral density (BMD) in older adults. The purpose of this study was to further evaluate the gradient of fracture risk based on TBS tertile categories and WHO BMD categories, adjusted for other risk factors. Using the Manitoba DXA registry, patients aged 40years and older with spine/hip DXA and L1-L4 TBS were identified. Any incident fractures, major osteoporotic fractures (MOF), and hip fractures were identified. Cox regression models were used to estimate unadjusted and covariate-adjusted hazard ratios (HR, 95%CI) for incident fracture by BMD and TBS category and for each SD decrease in BMD and TBS. The study population included 73,108 individuals, 90% female with mean age 64years. Mean (SD) minimum T-score was - 1.8 (1.1), and mean L1-L4 TBS was 1.257 (0.123). Lower BMD and TBS, both per SD, by WHO BMD category and by TBS tertile category, were significantly associated with MOF, hip, and any fracture (all HRs p < 0.001). However, the quantum of risk was consistently greater for BMD than TBS, with HRs showing non-overlapping CIs. TBS is complementary to BMD in prediction of incident major, hip, and any osteoporosis-related fracture, but reductions in BMD impart greater risk than reductions in TBS on both continuous and categorical scales.