Marked Disparity Between Trabecular and Cortical Bone Loss with Age in Healthy Men

Abstract

To define age-related changes in bone mineral content in normal men, radial (proximal and distal) and vertebral bone mineral content was measured in 62 men aged 30-92 yr. Radial bone mineral content (largely cortical bone) was measured by single photon absorptiometry, and trabecular vertebral content (T12, L1-L3) by computed tomography. Radial bone mineral content fell gradually (2-3.4% per decade) with age, but vertebral trabecular content fell more rapidly (12% per decade). Body size was not associated with the rate of bone loss from the distal radial and vertebral sites, but men with lower surface areas lost bone more rapidly at the predominantly cortical proximal radial site. The fact that radial cortical bone mineral content falls much less rapidly than vertebral trabecular content with age and is also associated with surface area indicates that trabecular and cortical bone compartments may be independently modulated. Age-related bone loss should not be considered a homogeneous process.