Vitamin D supplementation during pregnancy does not prevent asthma in offspring

Référence

Litonjua AA, Carey VJ, Laranjo N, et al. Six-year follow-up of a trial of antenatal vitamin D for asthma reduction. N Engl J Med 2020;382(6):525-533.

Sommaire

Previous studies have found an association between lower vitamin D levels in pregnant women and higher rates of asthma in their offspring. Pregnant women who had a history of asthma, eczema, or allergic rhinitis in themselves or their partner were recruited between 10 and 18 weeks of gestation. They were randomized to receive 4400 IU vitamin D or 400 IU vitamin D daily. The initial report of this trial found a reduced risk of asthma of borderline significance in treated children at 3 years of age (24.3% vs 30.4%; P = .051). This study is a follow-up through 6 years of age. The trial included 881 women who had 806 children of whom 52% were male with a low-ish mean maternal vitamin D level of 23 ng/mL. Asthma diagnosis was based on parent report of physician-diagnosed asthma, and recurrent wheeze was defined as use of asthma medications or reported wheeze. At age 6 years there was no difference in the incidence of asthma or recurrent wheeze, regardless of baseline vitamin D levels. There were some trivial differences in pulmonary function test results, but nothing important. There were also no harms to the mothers or fetuses from the high-dose vitamin D supplementation.