Vitamin D and Asthma: a Systematic Review of Clinical Trials

To perform a systematic review of prospective clinical trials to determine whether improving vitamin D status improves asthma control.

In cross sectional studies suboptimal viramin D status is often associated with poor asthma control. However, decreased 25-hydroxycholecalciferol (25 (OH) D) concentrations might not be causally associated with asthma control. We performed a systematic review until December 15, 2021 according to PRISMA guideline, searching MEDLINE, MEDLINE In-Process, Embase, Cochrane Database of Systematic Reviews, and Cochrane Central Register of Controlled Trials. Two searches were performed, the first using "vitamin D" and the second using "Vitamin D" or "ergocalciferol" or "cholecalciferol" and "Asthma". From 419 retrieved papers, after removal of duplicate and after using exclusion criteria, 28 full-text articles were eligible, of which 6 remained for quantitative analysis and 11 (9 studies) for qualitative analysis. From both analyses, prospective studies do not support that improving the vitamin D status of asthmatic children improves asthma control.