Vitamin D Supplementation for Treating Atopic Dermatitis in Children and Adults: A Systematic Review and Meta-Analysis

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease affecting up to 20% of children and 10% of adults worldwide. Current research suggests a correlation between serum vitamin D level and AD severity and that vitamin D supplementation could have a potential therapeutic effect on AD. Objectives: To conduct a systematic review and meta-analysis of studies of vitamin D supplementation for disease improvement in children and adults with AD. Methods: PubMed, EMBASE, and Cochrane were searched from 19 April to 20 April 2024. We included randomized controlled trials (RCTs) of patients with AD comparing an intervention group with a control group. The risk of bias of the selected studies was assessed using the Cochrane risk-of-bias tool for randomized trials. All analyses were conducted in R (v4.1.2; R Core Team 2021). Results: Eleven RCTs with 686 participants were included. The included trials had measured AD severity by using the SCOring Atopic Dermatitis (SCORAD) or the Eczema Area and Severity Index (EASI). Vitamin D supplementation significantly reduced AD severity compared with the control group (standardized mean difference = −0.41, 95% CI: −0.67 to −0.16, I2 = 58%, p < 0.01). Conclusions: Vitamin D supplementation reduces AD severity in children and adults. Larger-scale and longer-term studies are still needed to confirm this conclusion. This study has been registered on PROSPERO (CRD42024535014).