A prospective cohort study of cord blood 25(OH)D3 and food allergies in 6-month-old Chinese infants.

BACKGROUND Vitamin D is closely related to childhood allergic diseases, such as food allergies, atopic dermatitis, and asthma. However, it is unclear whether vitamin D status in the cord blood from mothers is related to food allergies in infants. OBJECTIVE We performed a prospective cohort study on the relationship between the cord blood vitamin D [i.e., 25-hydroxyvitamin D3(25(OH)D3)] level and infant food allergies. METHODS This study selected 741 newborns to observe until 6 months of age and used open oral food challenges (OFCs) to diagnose their food allergies. Cord blood and 6-month serum 25(OH)D3 levels of the infants were measured by liquid chromatography-tandem mass spectrometry. RESULTS The proportion of children with cord blood 25(OH)D3 deficiency (< 20 ng/mL) was 86.27%. Cord blood vitamin D was positively correlated with the supplementation frequency of egg yolk, multivitamins, calcium, and docosahexaenoic acid (DHA) during pregnancy and the mother's age. No significant difference was found in the cord blood 25(OH)D3 level between summer born and winter born infants (p = 0.465). After adjusting for seasonal factors, the risk of food allergies in the 25(OH)D3 non-deficiency group was 2.72 times that of the 25(OH)D3 deficiency group. Infants in the 25(OH)D3 non-deficiency group ≥20 ng/mL) had a higher risk of allergies compared with the deficiency group (< 20 ng/mL) (RR = 2.49). CONCLUSIONS Cord blood 25(OH)D3 is associated with infant food allergies. Maintaining 25(OH)D3 in maternal cord blood at a low level may be conducive to the prevention of infant food allergies.