Maternal asthma is a major risk factor for a child also developing asthma. A report examines whether vitamin D sufficiency in pregnancy can change that risk.
Childhood asthma is one of the most common respiratory diseases in children. Having a mother who has asthma is a strong risk factor for her offspring also having the condition. Recent research has shown that vitamin D is a modifiable prenatal exposure. A report from the Journal of Allergy and Clinical Immunology looked at the effect of both early and late prenatal vitamin D status in pregnancy in both women with asthma and without on the development of recurrent wheeze or childhood asthma.1
Investigators ran a cohort study that used prospectively collected data from the vitamin D Antenatal Asthma Reduction Trial, which was a randomized, double-blinded, placebo-controlled vitamin D supplementation trial in pregnant women who were at high risk of offspring asthma. The women were either randomized into the control group (a multivitamin containing 400 IU of vitamin D daily) or the intervention group (4400 IU of VD daily). The 25-Hydroxyvitamin-D (25(OH)D) level was measured early and late in the pregnancy. The main exposure for the study was an ordered variable that represented early and late prenatal vitamin D sufficiency (25(OH)D level ≥30 ng/mL) status in pregnant women with or without asthma.
The study included 776 mother-offspring pairs who had vitamin D measurements from both early and late pregnancy. Among the 766 children, 202 children either had physician-diagnosed asthma or recurrent wheeze before their third birthday. Children who had mothers with asthma had nearly 2 times odds of developing asthma or a recurrent wheeze by age 3 years when compared to those children with mothers who did not have asthma, even after adjusting for a number of variables including maternal income, maternal atopy, paternal asthma, preterm birth, child sex, and child race. An examination of early and late prenatal vitamin D status and its impact on offspring asthma or recurrent wheeze, the investigators noted a significant interaction seen between prenatal vitamin D and maternal status, with the highest decrease in risk of offspring asthma or recurrent wheeze seen among mothers with asthma who had prenatal vitamin D sufficiency at both measurements.
The investigators concluded that vitamin D sufficiency throughout pregnancy appears to have a protective role, particularly when mitigating the risk caused by maternal asthma on the development of childhood asthma or recurrent wheeze.
1. Lu M, Litonjua A, O’Connor G, et al. Effect of early and late prenatal vitamin D and maternal asthma status on offspring asthma or recurrent wheeze. Journal of Allergy and Clinical Immunology. 2021;147(4):1234-1241.e3. doi:10.1016/j.jaci.2020.06.041