A Systematic Review and Meta-analysis of Association between Serum Vitamin D and Atopic Dermatitis

Objective: The relationship between vitamin D and atopic dermatitis remains controversial. Here, we systematically reviewed and meta-analyzed the association between serum 25-hydroxy vitamin D concentration (25(OH)D) and atopic dermatitis (AD), AD severity, and the benefits of oral vitamin D supplementation. Methods: A total of 15 observational studies and 5 RCTs from 12 countries were included in this review. The effects of vitamin D deficiency or vitamin D level on AD and standardized AD severity score were performed using a random-effects model on 3 aspects: 1) serum vitamin D and risk of AD, 2) serum vitamin D level and severity of AD, and 3) the benefits of oral vitamin D supplementation on AD severity. Results: The analysis showed serum 25(OH)D deficiency marginally increased the risk of AD (OR = 1.55, 95%CI = 0.94 - 2.55, p = 0.084). Low serum 25(OH)D was correlated with greater AD severity (r = -0.29, 95%CI = -0.504 to -0.048, p = 0.020), and oral vitamin D supplementation helped reduced AD severity score by 0.963 standard deviation (95%CI = 0.23 to 1.70, p = 0.011). Conclusion: The association between serum 25(OH)D deficiency and risk of AD was still controversial. However, our meta-analysis suggested that higher serum 25(OH)D is associated with lower severity of AD. Moreover, oral vitamin D supplementation also helps to reduce AD severity. Keywords: Atopic dermatitis, vitamin D, systematic review, meta-analysi