Objective: There has been growing interest in vitamin D insufficiency as a predisposing factor for allergy development based on immunoregulatory properties and epidemiological studies. The aim of this study was to investigate the association between vitamin D exposure in utero and allergic outcomes in the first year of life.
Methods: Cord blood (CB) vitamin D was measured in 231 high-risk infants from an Australian prospective birth cohort. CB 25-hydroxyvitamin D(3) (25[OH]D(3)) concentration was analyzed in relation to maternal vitamin D intake and the development of infant eczema, allergen sensitization, and immunoglobulin E-mediated food allergy.
Results: Maternal intake of supplemental vitamin D was significantly correlated with CB 25(OH)D(3) concentration (ρ = 0.244, P = .003), whereas dietary vitamin D did not influence CB levels. There was significant seasonal variation in CB 25(OH)D(3) concentration suggesting that sunlight exposure was an important determinant. Lower CB vitamin D status was observed in infants that developed eczema (P = .018), and eczema was significantly more likely in those with concentrations <50 nmol/L in comparison with those with concentrations ≥ 75 nmol/L (odds ratio 2.66; 95% confidence interval 1.24-5.72; P = .012). This association remained significant after adjustment for multiple confounding factors. The associations between CB 25(OH)D(3) concentration and allergen sensitization, immunoglobulin E-mediated food allergy, and eczema severity (SCORing Atopic Dermatitis) were not significant.
Conclusions: Reduced vitamin D status in pregnancy may be a risk factor for the development of eczema in the first year of life, reinforcing the need to explore the role of vitamin D exposure during development for disease prevention.