(HealthDay News) — Vitamin D supplementation during pregnancy and infancy may reduce aeroallergen sensitization in children, according to a study published online April 6 in Allergy.

Cameron C. Grant, MBChB, from the University of Auckland in New Zealand, and colleagues conducted a randomized, double-blind, placebo controlled trial. Pregnant women (27 weeks of gestation to birth) and then their infants were randomized to receive placebo or one of two doses of daily oral vitamin D (placebo/placebo; 1,000 IU/400 IU; 2,000 IU/800 IU). Specific serum immunoglobulin (Ig)E antibodies were measured when the children were 18 months old.

Specific IgE was measured in 71% of 260 enrolled children. The researchers found that for four mite antigens: Dermatophagoides farina (Der-f1, Der-f2) and Dermatophagoides pteronyssinus (Der-p1, Der-p2), the proportion of children sensitized varied for placebo, lower-dose, and higher-dose vitamin D, respectively: 18, 10, 2%; 14, 3, 2%; 19, 14, 3%; and 12, 2, 3%, respectively (all P<0.05). Study group differences were seen in the proportion of children with primary care visits for asthma (11, 0, 4%, respectively; P=0.002), but not for other respiratory diagnoses.

“Vitamin D supplementation during pregnancy and infancy reduces the proportion of children sensitized to mites at age 18 months,” the authors write. “Preliminary data indicate a possible effect on primary care visits where asthma is diagnosed.”

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