Sex differences in cortical bone of humeral head region

Abstract Background Proximal humerus fractures are highly related to age, and are particularly high in women. The goal of this study was to investigate sex-related similarities and differences in humeral head structure. Methods Computed tomography (CT) scans of 147 healthy subjects (76 men /71 women) spanning a wide range of ages (20-88 years) were analyzed. Three groups of subjects were identified according to age: group A (aged 20-39 years), group B (aged 40-59 years), and group C (aged> 60 years). For each subject, cortical bone mapping (CBM) was applied to create color 3D thickness map for the proximal humerus. Regions of interest (ROI) were defined in three walls of humeral head which corresponded to the anterior, lateral and posterior aspects. Cortical parameters, including the cortical thickness (CTh), cortical mass surface density (CM), and the endocortical trabecular density (ECTD) were measured using CBM. Results In both sexes, the CTh value of proximal ROIs in lateral and anterior wall tended to decrease with age. No significant difference was detected between three age groups for each parameter in the posterior wall in men and women. In ROIs 1-9, the ECTD tended to show a notable decline with age in women. In contrast, the ECTD remained unchanged in men. When pooled across all decades, the CTh, CM and ECTD values of ROI 1-9 were approximately equivalent between men and women. Conclusions There was no sex difference in cortical bone parameters in the humeral head region. However, the endocortical trabecular density decreased significantly with age only in women.