Association of vitamin D levels and oral lichen planus. Systematic review and meta-analysis

Oral lichen planus (OLP) is an inmuno-mediated mucocutaneous chronical inflammatory disease. Multiple predisposing factors are considered, such as autoimmune response, microorganisms, medications, dental materials, psychological stress, genetic predisposition or nutritional deficiencies. The deficiency of vitamin D has been related to various autoimmune diseases like OLP. The electronic search was conducted in the MEDLINE (Pubmed), Scopus, Cochrane Library and Web of Science databases. To assess any potential risk of bias, the authors critically appraised each study by the Newcastle-Ottawa Scale for cohort and case-control studies. Pooled analyses were performed using a random-effects model. Heterogeneity of the studies was assessed by the I2 statistics. Forest Plots were performed to graphically represent the difference between vitamin D concentrations in the OLP compared to healthy group, with a 95% confidence interval. After applying our inclusion and exclusion criteria, 7 articles were included in our review. The median concentration vitamin D in ng/ml found in serum for patients with OLP was of 26,6311,75ng/ml and for healthy patients was of 31,438,7ng/ml. Regarding the quantitative analysis, 7 studies were included. The difference in the concentration of vitamin D in healthy patients and patients with OLP statistically significant (Weighted Mean Difference (WMD): -6.20, 95% CI: -11.24 to -1.15, p=0.02 and I2 heterogeneity: 94%, p