Vitamin D deficiency in the pathogenesis of hypertension: still an unsettled question.

Vitamin D deficiency is inversely associated with blood pressure and is felt to contribute to the genesis and maintenance of hypertension. Although well demonstrated in animal studies, in many clinical studies the association between vitamin D status and blood pressure has not been consistently observed or else has been quite small. These discrepancies may relate in part to methodological differences including: patient selection, study size and duration, and, in the case of vitamin D repletion studies, differences in the vitamin D supplement used, its dose, and dosing intervals. Polymorphisms in genes regulating vitamin D activation and function may explain some of the observed inconsistencies as suggested by recent studies. The present review examines experimental and clinical studies bearing on the inverse association between blood pressure and vitamin D status and concludes that a new definition of vitamin D deficiency using additional biomarkers may better select patients with hypertension who will respond to vitamin D supplementation.