Vitamin D May Reduce Asthma Exacerbations
Vitamin D supplementation reduced the rate of asthma exacerbations that required treatment with systemic corticosteroids, according to a recent meta-analysis.
For their systematic review and meta-analysis, the researchers identified 8 randomized, double-blind, placebo-control trials that included participants with asthma who received vitamin D2 or vitamin D3 supplementation or placebo. Seven studies provided individual participants’ data (955 participants) and were included in the final analysis.
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The incidence of asthma exacerbation requiring treatment with systemic corticosteroids was assessed as the primary outcome. In addition, subgroup analyses were used to determine whether the associations between vitamin D supplementation and asthma exacerbation were effected by baseline 25 hydroxyvitamin D (25[OH]D) concentration, age, ethnicity or race, body mass index, vitamin D dosing, use of inhaled corticosteroids, or end-study 25(OH)D levels.
Overall, vitamin D supplementation reduced the rate of asthma exacerbations requiring systemic corticosteroid treatment (rate ratio [RR] 0.74). However, there were no significant differences in the time to first asthma exacerbation or proportion of participants with at least 1 asthma exacerbation between the vitamin D and placebo groups.
In subgroup analyses, vitamin D supplementation was found to have a protective effect among participants with baseline 25(OH)D levels below 25 nmol/L but not among those with higher baseline 25(OH)D levels (RR 0.33 vs 0.77, respectively).
Additionally, analyses did not show the effects of vitamin D on asthma to be stronger in any one subgroup and showed no heterogeneity. Six studies were found to have a low risk of bias.
“Vitamin D supplementation reduced the rate of asthma exacerbations requiring treatment with systemic corticosteroids overall,” the researchers concluded. “We did not find definitive evidence that effects of this intervention differed across subgroups of patients.”
—Melissa Weiss
Reference:
Jolliffe DA, Greenberg L, Hooper RL, et al. Vitamin D supplementation to prevent asthma exacerbations: a systematic review and meta-analysis of individual participant data [published online October 3, 2017]. Lancet Respir Med. http://dx.doi.org/10.1016/S2213-2600(17)30306-5.