Therapy of osteoporosis with calcium and vitamin D.

Inadequate intakes of vitamin D and calcium lead to reduced calcium absorption, higher bone remodeling rates, and increased bone loss. Vitamin D insufficiency has also been linked to reduced muscle function and increased risk of falling. The mechanisms for the performance and muscle effects are not well understood. Administering vitamin D to those with inadequate vitamin D status has been shown to lower fracture rates in some trials but not in others. The purpose of this presentation is (1) to examine how calcium and vitamin D work in concert, (2) to consider key evidence that increasing vitamin D intake will affect risk of falls and fractures, and (3) to estimate the 25-hydroxyvitamin D [25(OH)D] level needed to achieve maximum fracture protection.