FIGURE 4.

Random-effects meta-analysis comparing the effects of daily 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 as a daily supplement. “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 no significant difference between D2 and D3 interventions in the raising of serum 25(OH)D concentrations when taken as a daily supplement (mean difference: 4.83; 95% CI: −0.98, 10.64; P = 0.10). D2, vitamin D₂; D3, vitamin D₃; IV, inverse variance; 25(OH)D, 25-hydroxyvitamin D.