Pathogenetic aspects of involutional osteoporosis.

The pathogenetic factors of postmenopausal and senile osteoporosis are reviewed. Both postmenopausal and senile osteoporosis occur as a result of a defective regulation of bone remodelling which leads to a negative uncoupling between bone resorption and bone formation. Systemic and local factors contribute to the development of the phenomenon. While studies of the systemic factors involved in age-related bone loss are well advanced, although still incomplete, the study of the local factors responsible at a tissue level for the negative skeletal balance has barely begun.