Cortical bone parameters measured at the one-third distal radius obtained with axial transmission and HR-pQCT compared with anthropometric data in a representative population

Fragility fractures remain an important health issue, in the context of aging populations. Ultrasonic measurement of cortical bone thickness (Ct.Th) and porosity (Ct.Po) at peripheral sites (forearm or leg) has been shown to be predictive of non-vertebral fragility fractures, with performance comparable with X-ray gold standard (DXA). Ultrasonic parameters (Ct.Th and Ct.Po) were measured using a Bi-Directional Axial Transmission (BDAT) device at the one-third distal radius. These values were validated, compared with site matched measurement of Ct.Th and volumetric Bone Mineral Density (Ct.vBMD) obtained with High Resolution peripheral Computed Tomography (HR-pQCT). Sixty-six participants (41 women, 25 men), aged 18 to 87 years old, with Body Mass Index (BMI) ranging from 16 to 30 kg.m⁻², were included. Significant linear correlations ($p<0.01$) were observed considering regular measurements: Ct.Th decreases with age and increases with Body Surface Area (BSA), height and weight. Opposite variations were observed for Ct.Po. Irregular measurements were associated with significantly older participants ($71\pm 10$ vs $49\pm 17$ y.o.) and with thinner ($2.3\pm 0.5$ vs $3.2\pm 0.6\mathrm{mm}$) and more porous ($10.9\pm 3.5$ vs $8.6\pm 3.3$ %) cortical bone with respect to regular measurements ($p<0.002$), while no significant differences were observed for other anthropometric data. It suggests that measurement irregularities can be associated with the trabecularization process. The integration of these reference values, with respect to anthropometric data (height, weight, BSA), should improve the detection of people at risk of fragility fractures using ultrasonic devices.