Wang M, et al. - Via this meta-analysis of 14 randomized, controlled trials involving 1,421 participants, researchers examined the link between vitamin D status and asthma-related respiratory outcomes. These trials were identified from PubMed, EMBASE, and Cochrane Library, and reported vitamin D supplementation in patients with asthma. The outcomes of interest were the rate of asthma exacerbation and predicted percentage of forced expiratory volume in first second, as well as asthma control test scores, fractional exhaled nitric oxide, interleukin-10, and adverse events. Reduction in the rate of asthma exacerbation was observed among participants who received vitamin D supplementation; this effect was particularly profound in patients with vitamin D insufficiency. In patients with air limitation and vitamin D insufficiency, the benefit of vitamin D had a positive impact on pulmonary function.