Effects of Vitamin D Levels and Supplementation on Atopic Dermatitis: A Systematic Review

Background: Atopic dermatitis (AD) is a chronic inflammatory skin condition affecting 5%-20% of children worldwide. Studies suggested both a correlation between serum vitamin D (VD) levels and AD severity and a therapeutic potential role for VD supplementation.

Objectives: To determine whether serum VD levels correlate with AD severity and the effects of supplementation for disease improvement in children.

Data Sources: Ovid MEDLINE, EMBASE, and Cochrane Library databases were searched.

Study Selection: Publications with children 0-18 years old with AD and data evaluating effects of VD levels or supplementation on AD severity were included.

Data Extraction: Author, year, inclusion criteria, study design, location, age, VD levels, VD supplementation regimens, and baseline and final disease severities were extracted.

Results: Of the 21 included publications, 15, 5, and 1 evaluated VD level, VD supplementation, and both factors with disease severity, respectively. There were 4 randomized control trials (RCTs), 5 cohort, 6 case-control, and 6 cross-sectional studies. A significant inverse correlation between VD level and severity was described in 62.5% (10/16) of studies. There were 67% (4/6) that reported a significant improvement in AD severity with supplementation.

Limitations: Studies meeting inclusion criteria were limited. Furthermore, papers were heterogeneous in terms of location, season, and VD supplementation regimen. Language and publication bias was another potential limitation.

Conclusion: In children, the majority of existing literature confirmed a link between serum VD levels and AD severity. Weak evidence was found supporting improvement of AD with VD supplementation. Future large-scale studies are needed to support our findings.