Relationship between vitamin D level and Bechcet's disease activity: A systematic review and meta-analysis.

Aim: In the present study, the evidence about the association between vitamin D deficiency and Behcet's disease activity was systematically reviewed and meta-analyzed. Method: We searched the English and Persian databases of Medline (Ovid), CINHAL, Scopus, Proquest, the Cochrane library and SID, IranDoc, Magiran, Iran Medex for articles published up until May 2018 with the keywords were related to serum vitamin D and active and inactive Behcet's disease in adults. Meta-analysis was done using the CMA software. Results: A total of 138 titles were retrieved and reduced to 80 titles after deletion of duplicates and finally after close assessing of titles and abstracts eight eligible studies including a total of 939 participants were identified for systematic review and meta-analysis. According to the results of the meta-analysis, the pooled effect size of the differences in the serum level of vitamin D in patients with inactive Behçet's Disease and healthy controls was [OR:-0.05; 95% CI:-2.05, 1.94; p = 0.95]. The serum vitamin D level was significantly lower in active patients compared with healthy controls [OR:1.21; 95%CI: -0.12, 2.31; p = 0.03]. The pooled effect size of the differences in the serum level of vitamin D in active and inactive Behçet's Disease was [OR:-0.71; 95%CI: -1.41, -0.007; p = 0.04] Conclusion: There is an association between vitamin D deficiency and active Behçet's Disease. Future studies investigating the association of vitamin D deficiency and Behçet's Disease needs to involve following information: dietary intake of calcium and vitamin D, measuring of sun exposure, report of drug consumption and physical activity level.