Fig. 3From: The effect of vitamin D supplementation on hemoglobin concentration: a systematic review and meta-analysisForest plot showing results of a meta-analysis on the effects of vitamin D supplementation on ferritin. Data were reported as SMDs with 95% CIs. (Toxqui study at 4, 8, 12 and 16 weeks after intervention, Panwar study at 1, 4 and 6 weeks after supplementation)Back to article page