Is cortical porosity in children determined by age-dependent osteonal morphology?
Structure of osteons and canals varied during growth. Large asymmetrical drifting osteons with giant active canals (remodeling space) predominated until the mid-teens and accounted for > 70% of childhood cortical porosity. Thereafter smaller concentric (adult type) osteons increasingly predominated. Gender differences may relate to greater fracture rates in boys, and race differences to greater fracture rates in whites. The role of osteocyte-mediated mechanotransduction in osteonal structure and cortical porosity during growth warrants further exploration.
The findings of the case-control and family-based studies clearly demonstrate that DNA sequence differences in eNOS gene influence the risk of cerebral vasospasm in subarachnoid hemorrhage.