Vitamin D During Pregnancy Could Lower Offspring Asthma Risk

Vitamin D sufficiency could help to reduce the risk of asthma among the offspring of pregnant women with asthma, according to the results of a recent study. 

The researchers conducted a cohort study of data from the Vitamin D Antenatal Asthma Reduction Trial, a randomized, double-blind, placebo-controlled trial involving 766 pregnant women with increased risk of offspring asthma. The women underwent vitamin D serum level measurement in early and late pregnancy. The main outcome of the study was offspring with asthma or recurrent wheeze at age 3 years.

Overall, the proportion of women with vitamin D sufficiency during the third trimester was higher than the proportion of those with sufficiency at baseline (420 of 766 [54.8%] vs 166 of 766 [21.7%], respectively [P < 0.001]). Vitamin D sufficiency status was not found to be different between women with and without asthma at either measurement point.

Of 766 offspring, 202 has either asthma or recurrent wheeze before age 3 years. After adjustment for maternal age, income, atopy; paternal asthma; treatment arm; study site; preterm birth; child sex; and race, children with mothers who had asthma had nearly 2-fold higher odds of asthma or recurrent wheeze than did those with mothers without asthma.

Among women with asthma, the researchers observed a decreasing trend in risk of offspring asthma or recurrent wheeze with increasing vitamin D sufficiency. However, in women without asthma, vitamin D status appeared to have no effect on the risk of offspring asthma or recurrent wheeze, and no differences were observed in risk of offspring asthma among women with vitamin D sufficiency at both measurements, regardless of asthma status.

“In conclusion, this study indicates a protective effect of prenatal VD sufficiency throughout pregnancy on the development of childhood asthma or recurrent wheeze by age 3 years, particularly in attenuating the increased baseline risk conferred by maternal asthma. Further studies may shed light on the underlying mechanisms, as this effect appears to interact with the genetic contribution from maternal asthma risk,” the researchers concluded.

—Michael Potts

Reference:

Lu M, Litonjua AA, O’Connor GT, et al. Effect of early and late prenatal vitamin D and maternal asthma status on offspring asthma or recurrent wheeze. JACI. Published online August 18, 2020. Doi: https://doi.org/10.1016/j.jaci.2020.06.041