Maternal serum 25-hydroxyvitamin D levels and infant atopic dermatitis: A prospective cohort study.

Background: Maternal vitamin D status during pregnancy has been linked with the risk of atopic dermatitis (AD) in children, while the results were inconsistent. The objective of this study was to assess the potential association.

Methods: Serum 25-hydroxyvitamin D (25(OH)D) levels were measured in pregnant women from the birth cohort MKFOAD. Infant AD was diagnosed according to Williams' criteria. Multivariate logistic regression model was used to examine the association of maternal serum 25(OH)D levels in the first, second, and third trimester of gestation with the risk of infant AD at first year of age.

Results: In total, 121 (26.5%) of 456 infants developed AD prior to 1 year of age. In general, higher maternal serum 25(OH)D levels throughout pregnancy were associated with increased risks of AD in infants prior to 1 year of age in multivariate logistic regression models, with borderline statistical significance in the first (per ln unit increase: adjusted OR = 1.93, 95% CI: 0.96, 3.88) and second (per ln unit increase: adjusted OR = 1.72, 95% CI: 0.93, 3.19) trimester. Multivariate logistic regression models using categorical variables of maternal 25(OH)D levels by tertiles showed similar results: Infants born to mothers with serum 25(OH)D levels in the highest tertile had higher risk of AD than those with 25(OH)D in the lowest tertile.

Conclusions: The present study found some evidence supporting that higher maternal 25(OH)D levels during pregnancy increased the risk of infant AD. However, the clinical implication of the findings should be limited for those with blood levels over the recommendations.