Alharthy, R. F.; Wong, A. K.; Szabo, E.; Yau, D.; Demaras, A.; Cheung, A. M.
To better estimate the risk of bone fractures, both bone mineral density (BMD) and microarchitecture should be measured. Dual-energy X-ray absorptiometry(DXA) scans are clinically used to provide information about BMD and can be used to determine trabecular bone score (TBS), which gives an estimate of trabecular microarchitecture for lumbar spine(L1-L4). High-resolution pQCT (HRpQCT) is an in vivo measurement of bone microstructure of the distal radius and tibia and its images can be converted to finite elements for estimation of bone strength.
This study assessed whether aBMD and TBS measured at central sites correlates with trabecular microstructure measured by HRpQCT at peripheral sites in men and women.
This cross-sectional analysis included participants from the Toronto cohort of CaMOS. HRpQCT and lumbar spine TBS were performed. Bone microstructure was determined from HRpQCT images and lumbar spine TBS from DXA scans. Correlations between HRpQCT and DXA measured indices in men and women were calculated.
197 participants were included (70M, 127F) with a mean age of 70 years. HRpQCT variables were significantly different among men and women with the exception of cortical vBMD (p=0.08) at distal radius. Correlations between aBMD at different skeletal sites and HRpQCT indices varied widely. The strongest correlation was seen at the ultra-distal radius (r ̴0.5-0.8, p<0.001). Femoral-neck, ⅓ radius, and total hip aBMD had low to moderate correlations. Lumbar spine TBS was the least correlated with HR-pQCT parameters, with the highest correlation between TBS and HR-pQCT being (r ̴0.2-0.3, p<0.05-0.001) at both distal radius and tibia (figure 1).
There is a clear difference in bone quality based on sex and age according to our assessment of bone microarchitecture and strength parameters. The weak association between lumbar spine TBS and peripheral HRpQCT indices may suggest that bone microstructure varies with site. Using them in combination may give a better understanding of overall fracture risk of an individual. Fig.