Lourdes Ramirez, MD
Allergy and Clinical Immunology
Lourdes G. Ramirez*, MD; Kathleen Lee-Sarwar, MD, MS; Scott T. Weiss, MD, MS; Augusto A. Litonjua, MD, MPH
Background: The risk of asthma and wheeze during childhood is multifactorial, and the role of prenatal and early life exposures, specifically vitamin D supplementation, in the development of asthma is not fully understood.
Objective: Describe the association of prenatal and postnatal vitamin D on asthma outcomes in participants of the Vitamin D Antenatal Asthma Reduction Trial (VDAART)
Methods: 748 mother-offspring pairs were classified into four groups based on randomization to high versus standard-dose vitamin D supplementation during pregnancy and offspring vitamin D exposure sufficiency during infancy based on vitamin and formula intake: “Both” – high maternal dose/sufficient infant vitamin D; “Neither” – standard-dose/insufficient; “Mother” – high-dose/insufficient and “Infant” – standard-dose/sufficient. We used logistic regression to test the association between vitamin D exposure and asthma/recurrent wheeze by age 3 years, asthma at age 6 years and atopic asthma at age 6 years.
Results: Asthma/wheeze at 3 years was least frequent in the “Mother” group (aOR compared to “Neither” 0.40, 95% CI 0.15-0.98, p = .05). When evaluating postnatal vitamin sufficiency by drops, we found the “Infant” group that received < 32 ounces/day of formula (versus ≥ 32 ounces/day) had reduced atopic asthma (OR compared to “Neither” 0.29, 95% CI 0.09-0.81, p = .02) at age 6 years. We did not find other significant associations with active or atopic asthma at age 6 years.
Conclusion: High-dose prenatal vitamin D supplementation is associated with reduced asthma/wheeze at age 3 years in infants with insufficient postnatal vitamin D supplementation, and postnatal vitamin D supplementation sufficiency derived from drops is associated with reduced atopic asthma at age 6 years in infants consuming < 32 ounces/day of formula.
This study expands our understanding of the role and optimal timing of vitamin D supplementation for childhood asthma prevention. Defining whether supplementation prenatally and/or throughout infancy differentially affects asthma outcomes will help shape current nutritional guidelines for expecting mothers and infants and potentially provide a practical and cost-effective strategy to modify childhood asthma risk.