High-dose vitamin D

Summary: Background: Systematic reviews have suggested a beneficial effect of vitamin D supplementation in reducing asthma exacerbations and respiratory infections, with an underrepresentation of individuals with severe asthma and preschoolers. We aimed to examine the efficacy and safety of high-dose vitamin D supplementation for reducing severe exacerbations in preschool-aged children with viral-induced, high-morbidity, and asthma.

Methods

In this randomised, placebo-controlled, parallel-group, triple-blind, multicentre trial, children aged 1–5 years with prior viral-induced exacerbations requiring oral corticosteroids (OCS) were enrolled across nine paediatric asthma centres in Canada. Participants were randomly assigned to receive either two oral boluses of 100,000 IU (3·5 months apart) with daily 400 IU vitamin D3, or placebo boluses and daily placebo, over 7 months. The primary outcome was the rate of exacerbations requiring rescue OCS during the 7-month follow-up, analysed by a negative binomial regression model. Secondary outcomes included laboratory-confirmed respiratory infections, health care utilisation, duration and severity of exacerbations, and safety. This trial was prospectively registered with ClinicalTrials.gov ( NCT03365687 ).