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Principal findings and comparison with other studies 31 Because of the conflicting evidence, limitations of previous reviews, and availability of new data, we aimed to conduct a systematic review and meta-analysis of randomised controlled trials to evaluate the effect of vitamin D supplementation on all cause mortality.
#CALCULATING HARBORD EGGER BIAS REVMAN 5 TRIAL#
Among these trials, the Vitamin D and Omega 3 Trial (VITAL) did not confirm the benefit of vitamin D supplementation on mortality. Recently, additional trials 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 assessing the effect of vitamin D supplementation on mortality have become available, which have approximately doubled the number of trial participants. 12 13 14 15 Additionally, these reviews lack sufficient detail (eg, community versus institution settings), and trial sequential analysis showed that the pooled sample size failed to meet the optimum size. 5 10 11 Interpretation of these reviews is difficult because they include trials of vitamin D administered with calcium, which has been associated with uncommon but important side effects (eg, cardiovascular events). 6 7 8 9 Previous systemic reviews and meta-analyses of randomised controlled trials suggested that vitamin D supplementation has a small effect on total mortality. Observational studies have revealed an inverse association of vitamin D status and mortality.
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3 4 5 If adequate vitamin D concentrations were to reduce risk of death from a wide variety of medical conditions, vitamin D supplementation would be a safe, economical, and widely available method to reduce mortality.Ĭlinical data examining the effect of vitamin D supplementation on mortality reduction are inconsistent. 1 2 Therefore, supplemental vitamin D has been viewed as a potential strategy for preventing non-skeletal chronic diseases. Evidence from observational studies indicates that low vitamin D status is associated with higher mortality from life threatening conditions such as cancer and cardiovascular disease. Vitamin D supplementation has been advocated for maintaining or even improving musculoskeletal health.