Serum level of vitamin D in patients with recurrent aphthous stomatitis: A systematic review and meta-analysis of case control studies.

Objectives: Recurrent aphthous stomatitis (RAS) is an ulcerative condition with unknown etiology. The effect of vitamin D in the etiology of RAS is still a matter of controversy. In this study, we aimed at review the available evidence on the role of vitamin D deficiency in RAS etiology.

Material And Methods: PubMed, Cochrane Library for Systematic Reviews, ISI Web of Science, Scopus, and EmBase were systematically searched for evidence on RAS and vitamin D up to January 2020. Retrieved records were screened and assessed by two of the authors independently. Newcastle-Ottawa scale was used to assess the quality of individual studies. AMSTAR tool was used for assessing the quality of the study.

Results: Eight studies including 383 healthy control and 352 patients with RAS were eligible for the meta-analysis. Serum vitamin D levels were significantly lower in RAS patients. The weighted mean difference was -7.90 (95% CI: -11.96 to -3.85).

Conclusions: The results highlighted the importance of vitamin D deficiency in the etiology of RAS. However, more studies are needed to reach a robust decision. The observed association between vitamin D and RAS is probably due to the effect of vitamin D on the immune system.