Elderly men and women with similar areal bone density show significant differences in bone microstructure and fracture pattern

Abstract

Objective To compare bone microarchitecture and fracture patterns between elderly men and women with similar spine and hip bone mineral densities (BMDs). Subjects and methods Twenty-eight men and 84 age-BMI-BMD-matched women aged 65 years and older with at least one major osteoporotic fracture underwent laboratory tests, dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and trabecular bone score (TBS). Results There were no sex differences in biochemistry, BMD or lowest T-scores. TBS values were low in 67% of the cohort and significantly correlated with HR-pQCT parameters. At HR-pQCT evaluation, men had greater bones (total area and cortical perimeter at distal radius and tibia) and better trabecular vBMD and microstructure at distal radius, but similar values for cortical vBMD and cortical thickness. When compared with Brazilian age-sex-reference HR-pQCT data from healthy individuals, all parameters tested were numerically lower in the study group. These differences seemed more pronounced in men, particularly for cortical thickness at the distal tibia, where relative deficits reached -46.9% in men and -35.4% in women. There was no sex difference in vertebral fractures, but wrist and shoulder fractures were more common in women (p = 0.006), whereas hip fractures were more common in men (p = 0.03). Conclusion To achieve similar DXA values, men appear to have greater relative bone deficits than women when compared to age-sex-matched healthy Brazilian population. This study highlights the importance of HR-pQCT to understand sex-specific differences in fracture pattern in the study population.