title: [Mechanisms of bone loss in osteoporosis].
abstract: Aging and menopause are the two main determinants of osteoporosis, a rarifying osteopathy due to bone loss. Type I osteoporosis observed in post-menopausal women is characterized mainly by trabecular bone loss results from an unbalanced coupling between resorption and formation inducing a thinning of trabeculae and from an increased osteoclast activation resulting in irreversible trabecular perforation. Anti-osteoclastic drugs prevent trabecular and cortical bone loss. Drugs that stimulate osteoblastic proliferation thicken trabecular plates but do not restore the normal trabecular microarchitecture after complete destruction of a large number of trabeculae. In type II osteoporosis, cortical bone loss is favoured by secondary hyperparathyroidism and is responsible for hip fracture. Calcium and vitamin D supplementations decrease the risk of hip fractures by reducing the secondary hyperparathyroidism.
authors.affiliation: INSERM unité 403, Faculté Alexis Carrel, Lyon.
authors.forename: P
authors.initials: P
authors.lastname: Chavassieux
authors.forename: P J
authors.initials: PJ
authors.lastname: Meunier
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D010024:Osteoporosis / Q000188:drug therapy / Q000503:physiopathology*; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy / Q000503:physiopathology*
vernacular_title: Mécanismes de la perte osseuse dans les ostéoporoses.