[Osteoporosis and osteomalacia].

The pathogenesis, clinical course and treatment of senile-postmenopausal osteoporosis are reviewed. It is likely that several factors, including genetic and racial determinants as well as nutritional calcium and/or vitamin D deficiency in the elderly play a pathogenic role. Available data are consistent with the possibility that the primary alteration of bone metabolism in senile-postmenopausal osteoporosis may be a decrease in de-novo bone formation below the level necessary to compensate for age-related bone loss. The second part of the study deals with the osteomalacia syndrome. The most common known causes of osteomalacia are vitamin D deficiency, especially secondary to malabsorption, and a defective vitamin D metabolism associated with chronic renal insufficiency or prolonged anticonvulsant therapy. The hypophosphatemic forms of osteomalacia may be induced by renal tubular dysfunction or by phosphate deficiency of other origin; in these disorders a pathogenic role of altered vitamin D metabolism has not yet been established.