Childhood asthma developmental programming is complex. Maternal asthma is a strong risk factor for childhood asthma, while vitamin D (VD) has emerged as a modifiable prenatal exposure.
To examine the combined effect of early and late prenatal VD status in pregnancies with and without asthma on childhood asthma/recurrent wheeze development.
We conducted a cohort study using prospectively collected data from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized, double-blinded, placebo-controlled vitamin D supplementation trial in pregnant women at high risk of offspring asthma (N=806 mother-offspring pairs). 25-hydroxyvitamin-D [25(OH)D] was measured in early and late pregnancy. Our main exposure was an ordered variable representing early and late prenatal VD sufficiency [25(OH)D>30ng/mL)] status in pregnancies with and without asthma. The primary outcome was offspring asthma or recurrent wheeze by age 3 years. We also examined the effect of prenatal VD on early life asthma/recurrent wheeze progression to active asthma at age 6 years.
Among maternal asthmatics, compared to those with early and late prenatal VD insufficiency, those with early or late VD sufficiency (aOR=0.56; 95% CI 0.31-1.00) or early and late VD sufficiency (aOR=0.36; 95% CI 0.15-0.81) had lower risk of offspring asthma/recurrent wheeze by age 3 years (P=0.008). This protective trend was reiterated in asthma/recurrent wheeze progression to active asthma from age 3 to 6 years (P=0.04).
This study implicates a protective role for VD sufficiency throughout pregnancy, particularly in attenuating the risk conferred by maternal asthma on childhood asthma/recurrent wheeze development.
Early identification and correction of vitamin D insufficiency in asthmatic pregnant women have implications for the prevention of early offspring asthma/recurrent wheeze and the persistence of offspring asthma to later childhood.
Copyright © 2020. Published by Elsevier Inc.