FRIDAY, July 8 (HealthDay News) -- Vitamin D3, but not other forms of vitamin D, is associated with reduced overall mortality, according to a review published in the July issue of the Cochrane Database of Systematic Reviews.
Goran Bjelakovic, M.D., Dr.Med.Sci., from the University of Nis in Serbia, and colleagues reviewed the available literature to evaluate the effects of vitamin D for prevention of mortality in adults. A total of 50 randomized trials were included, involving 94,148 participants, predominantly women, with a mean age of 74 years. The participants received vitamin D for a median of two years, at any dose, duration, and route; placebo; or no intervention. Risk ratios (RRs) were calculated and risk of bias was considered. Trial sequential analyses were performed to minimize the risk of random errors.
The investigators found that vitamin D intake decreased overall mortality (RR, 0.97; 95 percent confidence interval, 0.94 to 1.00; I² = 0 percent). A separate assessment of different forms of vitamin D (32 trials) showed a significant decrease in mortality with vitamin D3 (RR, 0.94; I² = 0 percent), which was not seen with vitamin D2, alfacalcidol, or calcitriol. A trial sequential analysis showed that the treatment of 161 individuals with vitamin D3 was needed to prevent one additional death. Vitamin D3 combined with calcium significantly increased nephrolithiasis (RR, 1.17; I² = 0 percent), while alfacalcidol and calcitriol were found to increase hypercalcemia (RR, 3.18; I² = 17 percent).
"Our analyses suggested that vitamin D3 reduces mortality by about 6 percent," the authors write.
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