Bone Structural Parameters as Measured by 3-Dimensional Dual-Energy X-Ray Absorptiometry Are Superior in Black Women...

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.

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.

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.

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.