Effect of Vitamin D Supplementation on Improvement of Symptoms in Mild-to-Moderate Asthma Patients with Vitamin D Insufficiency and Deficiency

BACKGROUND: In the current study, we assessed the effect of vitamin D supplementation on improvement of symptoms in mild-to-moderate asthma patients with vitamin D insufficiency and deficiency. MATERIALS AND METHODS: This randomized, controlled clinical trial included 132 mild-to-moderate asthma patients with vitamin D insufficiency (n=66) and those with vitamin D deficiency (n=66). They were assigned randomly to two groups of cases (with two subgroups) and controls (with two subgroups). In the case subgroups, for patients with vitamin D deficiency, a dose of 50,000 U vitamin D supplementation was administered orally on a weekly basis and for six weeks followed by a maintenance dose of 1000 U daily. For patients with vitamin D insufficiency, a dose of 1000 U vitamin D supplementation was prescribed daily. In control group, we administered placebo. The information including asthma symptoms, parameters measured by spirometer (Forced Vital Capacity-FVC, Forced Expiratory Volume in one second-FEV1) and 25-hydroxyvitamin D [25(OH)D] concentration was collected at baseline and three months later and analyzed using SPSS, Version 20. RESULTS: Improvement of FEV1/FVC ratios were found in both groups but this improvement in both case subgroups of patients with vitamin D insufficiency and deficiency suggested more appropriate results compared to control group (P-value=0.022). Moreover, the correlation between changes in 25(OH)D level and changes in FEV1 was positive and significant in patients receiving vitamin D supplementation within a three-month follow up (r=0.202, P-value=0.042). CONCLUSION: According to the results, vitamin D supplementation can be associated with the improvement of asthma symptoms and lung function in mild-to-moderate asthma patients with vitamin D insufficiency and deficiency.