Background: Trials in school-aged children suggest vitamin D supplementation reduces asthma exacerbations.
Aims: To examine whether vitamin-D3 (100,000IU) raises serum 25-hydroxy-vitamin D (25OHD) and ascertain the feasibility for a large-scale intervention in preschoolers.
Methods: In a 6-month, double-blind, randomised, placebo-controlled, pilot trial, children aged 1-5 years with viral-induced asthma were allocated to receive orally 100,000IU vitamin-D3 (intervention) or identical placebo (control), plus 400IU vitamin-D3 daily for six months. Serum 25OHD was measured at baseline, 10days, 3 and 6 months. Outcomes included the group difference in 25OHD change from baseline (Δ25OHD) at 3 months (primary); the proportion of children with 25OHD ≥75nmol/L at 3 months (secondary); and health event rates.
Results: Twenty-two children were randomised (intervention:11; control:11). At 3 months, the group difference in Δ25OHD (7.2nmol/L; 95%CI: -13.7, 28.1) was not significant; yet, 100% versus 54.5% (intervention versus control) had serum vitamin D ≥75nmol/L. Overall, there was a significant group, time, and group*time effect on 25OHD, in favour of the intervention, with a significant group difference in Δ25OHD at 10days (110.3nmol/L; 95%CI: 64.0, 156.6). Group rates for oral corticosteroids were 0.82 and 1.18/child (intervention versus control; Rate Ratio=0.68; 95%CI: 0.30, 1.62).
Conclusion: Following 100,000IU vitamin-D3, all children reached a serum vitamin D level ≥75nmol/L, compared with half those who received placebo. Daily supplementation, sun exposure and insufficient power may explain the absence of a significant 3-month group difference in Δ25OHD. Oral corticosteroid rates suggest an effect size concordant with previous trials.
Funding source: Thrasher Research Fund