Bone microarchitecture and estimated strength in 499 adult Danish women and men: a cross-sectional, population-based...

High-resolution peripheral quantitative computed tomography (HR-pQCT) allows in vivo assessment of cortical and trabecular bone mineral density (BMD), geometry, and microarchitecture at the distal radius and tibia in unprecedented detail. In this cross-sectional study, we provide normative and descriptive HR-pQCT data from a large population-based sample of Danish Caucasian women and men (n = 499) aged 20-80 years. In young adults (<35 years), women (n = 100) compared to men (n = 64) had smaller total and cortical areas, inferior metric trabecular indices, higher network inhomogeneity, lower cortical porosity, and lower finite element estimated bone strength. The changes in parameters with age were estimated from multiple regression analyses. In men, with age the greatest changes (from parameter minimum or maximum) until 80 years were found for cortical porosity (1.91 IQR), BV/TV (-1.09 IQR), and trabecular thickness (-0.87 IQR) in the radius and BV/TV (-1.55 IQR), cortical BMD (-1.25 IQR), and cortical porosity (1.25 IQR) in the tibia. In women changes were most pronounced for cortical porosity (4.76 IQR), trabecular inhomogeneity (3.84 IQR), and cortical BMD (-2.86 IQR) in the radius and cortical BMD (-5.06 IQR), cortical porosity (3.86 IQR), and cortical area (-1.64 IQR) in the tibia. These findings emphasize the age- and sex-related differences in bone morphology, with men having a structural advantage over women from early adult life translating into superior indices of bone strength. With age women are further disadvantaged compared to men by greater decrements in cortical and trabecular architecture in the radius and cortical architecture in the tibia.