Clinical, biochemical, radiographic, epidemiologic, and economic features of osteoporosis.

Osteoporosis is a clinical syndrome characterized by low bone mass and fracture, primarily of vertebrae, hip, and distal forearm. Many factors play a role in the pathogenesis of the final clinical event, the fracture. In some patients an initial deficiency or rapid loss of trabecular bone may result in vertebral collapse. In others, loss of cortical bone may result in hip fracture. Fracture itself may occur not only because of low bone mass but also because of other factors intrinsic to bone, such as accumulation of microdamage, or extrinsic to bone, such as poor coordination or frequency of trauma. The many factors that play a role in the pathogenesis of the disorder may appear confusing; however, they provide several areas in which therapeutic intervention may prove to be value to the patient.