Figure 3.

(A) displays the overall impact of vitamin D on chronic pruritus, as measured by the visual analog scale, compared to the placebo. (B–D) show subgroup analyses corresponding to (A): (B) examines the effect based on the duration of treatment, (C) focuses on the specific disease diagnosis, and (D) considers the method of treatment administration. The pruritus-relieving effect of vitamin D is represented by squares, which indicate the standardized mean difference, with the squares shifting to the left to signify a reduction in pruritus. The horizontal lines through the squares depict the 95% confidence intervals, while the diamond symbol represents the pooled effect size [2,3,15,17,34,35,36,37,38].