Background and objectives: Cow milk allergy is the most common food allergic disease in young infants and vitamin D has a critical role in regulating intestinal inflammation.
Methods and study design: To determine roles of vitamin D in cow milk allergy, fifty-six young infants with cow milk allergy were enrolled. The serum 25-hydroxyvitamin D (25OHD), total and specific IgE, circulating regulatory T lymphocytes, and blood eosino-phil counts were determined.
Results: The serum 25OHD in cow milk allergy and age-matched infants were sim-ilar (68.3±38.9 nmol/L versus 72.9±33.1 nmol/L, p>0.05), 71% Cow milk allergy infants (40/56) had serum 25OHD lower than 75 nmol/L compared to 66% (37/56) in the controls. The cow milk allergy infants with 25OHD lower than 75 nmol/L had persistent blood eosinophilia and delayed resolution of symptoms after cow milk elimination compared to those with 25OHD above 75 nmol/L (odd ratio 3.7, 95% CI 1.1-12.6, p<0.05). The serum 25OHD inversely correlated with blood eosinophil counts after cow milk elimination (r=-0.37, p<0.01). Cow milk allergy infants with 25OHD lower than 50 nmol/L (vitamin D deficiency, n = 22) were in general at younger age (1.6±0.6 months) compared to infants with insufficient (50-75 nmol/L) or normal (>=75 nmol/L) group (4.3±1.2 and 4.6±0.9 months, respectively, p<0.001).
Conclusions: Low serum vitamin D associates with persistent blood eosinophilia and symptoms in young cow milk allergy infants.