Comment to: ‘Meta-analysis of long-term vitamin D supplementation on overall mortality’

 

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  Figure 1

Figure 1. Intervention effect of vitamin D3 and vitamin D2 vs placebo or no intervention on mortality.

 Figure 2

Figure 2. Trial sequential analysis of 20 vitamin D3 trials with low risk of bias. The diversity-adjusted required information size (DARIS) was calculated based on mortality in the control group of 10%; relative risk reduction of 5% in the experimental group; type I error of 5%; and type II error of 20% (80% power). No diversity was noted. The required information size was 110,505 participants. The cumulative Z-curve (blue line) did not cross the trial sequential monitoring boundaries for benefit (red line) at any time. Accordingly, the crossing of the conventional statistical 5% boundary (the horizontal brown line) may be due to random errors.