FIGURE 3.

Random-effects meta-analysis comparing the effects of bolus supplementation of D3 with that of D2 on net changes in serum 25(OH)D concentrations. The forest plot indicates that the absolute change in 25(OH)D from baseline favored the D3 intervention when administered as a bolus dose. In the figure, “Δ25(OH)D” denotes the change in serum 25(OH)D concentrations from baseline (net change), squares denote mean differences [with 95% CIs (lines)], and “Total” denotes the cumulative n from all included studies. With the use of a random-effects model, overall, there was a significantly greater effect in the raising of serum 25(OH)D concentrations over time for D3 supplementation as a bolus dosage (single and multiple bolus) than for D2 supplementation (mean difference: 34.10; 95% CI: 16.38, 51.83; P = 0.0002). D2, vitamin D₂; D3, vitamin D₃; IV, inverse variance; 25(OH)D, 25-hydroxyvitamin D.