[Vitamine D in patients with osteoporosis: sufficient or necessary?].

Vitamin D is essential for intestinal calcium absorption, bone mineralisation and plays an important role in neuromuscular functions. Vitamin D insufficiency is highly prevalent among postmenopausal women with osteoporosis and in the elderly. In turn, supplements of vitamin D3 (cholecalciferol), and to a lesser extent vitamin D2 (ergocalciferol), may decrease falls and fracture risk by 25%. Despite some recent negative studies, the actual question is not to know whether vitamin D is necessary, but rather how much vitamin D is sufficient to prevent secondary hyperparathyroidism, falls and fractures. Moreover, the risk of osteoporosis and of fragility fractures may be influenced by genetic variation in the vitamin D receptor (VDR).