Gestational, umbilical cord vitamin D levels don’t predict atopic disease in offspring

Vitamin D levels measured in maternal sera during gestation and in umbilical cord blood were not predictive of the prevalence of eczema, food allergy, asthma and allergic rhinitis in children at ages 2 years and 5 years, according to study results published in the journal Allergy.

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Áine Hennessy, PhD, from the School of Food and Nutritional Sciences at the University College Cork (Ireland), and her colleagues performed a prospective cohort study of 1,537 women in the Cork BASELINE Birth Cohort Study who underwent measurement of serum 25-hydroxyvitamin D (25[OH]D) from maternal sera followed by measurement of 25(OH)D in umbilical cord blood (1,050 cases). They then measured the prevalence of eczema, food allergy, allergic rhinitis, and asthma in infants at aged 2 and 5 years.

The researchers found at 2 years old, 5% of infants had persistent eczema, 4% of infants had a food allergy and 8% of infants had aeroallergen sensitization. At age 5 years, 15% of infants had asthma, while 5% had allergic rhinitis. Mothers whose children went on to have atopy did not differ in their 25(OH)D levels at 15 weeks’ gestation (mean 58.4 nmol/L vs. 58.5 nmol/L) or in the levels in umbilical cord blood (mean 35.2 nmol/L and 35.4 nmol/L).

Of the women in the cohort, 74% ranged in age from 25 to 34 years; 49% reported a personal history of allergy and 37% reported a paternal allergy. The mean birth weight of the infants was 3,458 g; infants were breastfed for mean 11.9 weeks, 73% of infants were breastfeeding by the time they left the hospital and 45% of infants were breastfeeding by age 2 months.

Limitations of the study included that parental atopy status was self-reported and that the researchers noted they did not examine genetic variants of immunoglobulin E synthesis or vitamin D receptor polymorphisms.

“To fully characterize relationships between intrauterine vitamin D exposure and allergic disease, analysis of well‐constructed, large‐scale prospective cohorts of maternal‐infant dyads, which take due consideration of an individual’s inherited risk, early‐life exposures and environmental confounders, is still needed,” Dr. Hennessy and her colleagues wrote.

The study was funded by grants from the European Commission, Ireland Health Research Board, National Children’s Research Centre, Food Standards Agency and Science Foundation Ireland. The authors report no relevant conflicts of interest.

SOURCE: Hennessy A et al. Allergy. 2018 Aug 7. doi: 10.1111/all.13590.