Osteoporosis is characterised by decreased trabecular bone mass in which both the mineral and the matrix are decreased to the same extent, but there is no gross abnormality of bone composition Although cortical bone is also affected, trabecular bone loss is most striking. Subtle chemical defects in mineral or matrix (bone proteins such as type-I collagen) may exist in some patients. This disease accounts for more than ninety per cent of patients with osteopenia.
There are no detectable abnormalities in calcium or phosphate homeostasis in osteoporosis.
