PURPOSE OF REVIEW
To summarize recent findings on vitamin D deficiency and mortality. The serum concentration of 25-hydroxyvitamin D [25(OH)D], the metabolic precursor of the vitamin D hormone calcitriol, is the standard for assessing vitamin D status. Deficient 25(OH)D concentrations (<25 nmol/l) are prevalent in Europe and North America.
Several large nonrandomized studies indicate that different from adequate 25(OH)D concentrations (>75 nmol/l), deficient 25(OH)D concentrations are associated with excess mortality in the general population and in patients with increased cardiovascular disease risk. Results support an earlier meta-analysis of controlled trials that were not primarily designed to assess mortality showing a survival benefit of vitamin D supplementation over no supplementation in middle-aged and elderly persons. In patients with advanced chronic diseases such as end-stage heart failure, however, circulating calcitriol predicts mid-term mortality better than 25(OH)D does. Available data indicate that these patients may enter a vicious cycle of low calcitriol, increased inflammation markers, and renal impairment, which may be difficult to escape by simple vitamin D supplementation.
Accumulating evidence suggests that vitamin D deficiency is linked to excess mortality. However, future studies should clarify to which extent vitamin D supplementation can improve survival in the aging population and in specific patient groups.