Effect of Vitamin D3 Supplementation on Severe Asthma Exacerbations in Children With Asthma and Low Vitamin D Levels: The VDKA Randomized Clinical Trial

RCT (n=192) found that vitamin D3 supplementation, compared with placebo, did not significantly improve the time to a severe asthma exacerbation (240 days vs 253 days for vitamin D and placebo respectively, HR 1.13, 95%CI=0.69-1.85).

Journal of the American Medical Association