Therapeutic effect of vitamin D supplementation on allergic rhinitis

Purpose In this study, we aimed to determine whether short-term (2 months) vitamin D supplementation could improve the allergic symptoms in AR patients. Methods A randomized double-blind placebo-controlled clinical trial was performed on allergic rhinitis patients with vitamin D deficiency from Nov. 2017-2018. 80 cases with allergic rhinitis and vitamin D deficiency were divided into two groups and vitamin D plus routine antihistamine medication (cetirizine) was prescribed for the study group, whereas the control group received cetirizine plus placebo. The clinical symptoms questionnaire was completed at baseline and after 4 and 8 weeks of treatment initiation. Vitamin D levels were re-measured at the end of the 8-week treatment course. Results In total, 80 patients with allergic rhinitis and vitamin D deficiency were enrolled. Among them, 35 cases and 33 controls visited the clinic after 8 weeks; the mean age in the aforementioned groups was 29.68 years and 29.13 years demonstrating no meaningful difference (P > 0.05). At study initiation, the mean vitamin D level was 14 ng/ml and 14.67 ng/ml in the study and control groups, respectively, indicating no significant difference (P = 0.189). The mean serum vitamin D level at 8 weeks of treatment in the study group (24.08 ng/ml) indicated a statistically meaningful difference with the mean vitamin D level at baseline (P < 0.001). Comparison of the mean scores of symptoms severity showed no significant difference between the two groups at study initiation and 4 weeks later (P = 0.073), whereas a significant difference was obtained between baseline and 8 weeks of treatment initiation (P = 0.007). Conclusion Based on the findings of the present study, it can be concluded that vitamin D supplementation along with antihistamines can result in relative symptoms improvement in AR patients with vitamin D deficiency.