Should the Concentration of Vitamin D be Measured in All Patients with Hypertension?

With mounting evidence indicating the direct effect of vitamin D on the vascular smooth muscle cell, endothelial function and the renin-angiotensin-aldosterone system, it is clear that randomized trials of vitamin D replacement and renin and angiotensin inhibition in patients with hypertension and vitamin D deficiency are warranted. Preliminary research has shown an inverse relationship between BP and vitamin D levels, and supplementation appears promising. To that end, we have just initiated a randomized clinical trial evaluating the effects of vitamin D and/or a renin inhibitor on ambulatory and clinic BP in vitamin D deficient patients with hypertension (clinical trials.gov identifier NCT00974922). The high prevalence of vitamin D deficiency and insufficiency, particularly in northern latitudes and during the winter months, supports determining 25-hydroxyvitamin D levels in patients with hypertension and supplementation provided to those whose levels are \u3c 30 ng/ml. It is noteworthy that recommended 25-OH D levels of \u3e 30 ng/ml (75 nmol/L) are unlikely to be achieved with the previous recommendation of 200 IU for younger people and 600 IU of vitamin D for older adults [3]. Doses of vitamin D3 from 1000 to 2000 IU daily are often required [4,25]. For every 100 IU of vitamin D ingested, the levels in patients with vitamin D deficiency should increase by 1 ng/ml [4]. Therefore, to bring most of the adult population to levels of \u3e 30 ng/ml, vitamin D supplementation of 1000 IU would be required in most, but even doses as high as 4,000 I.U. are safe for short-term ‘loading’, and would bring about 90% of the population to levels above 30 ng/ml within a few weeks