Serum vitamin D levels in patients with oral lichen planus: A systematic review and meta-analysis

Aims: Vitamin D is an indispensable vitamin which is actively engaged in immune upregulation. Several studies have been conducted to explore the association between vitamin D and oral lichen planus (OLP), but the results are still inconclusive. This meta-analysis was performed to understand the association of serum vitamin D levels in OLP. Methods: A search was conducted for observational studies that inspected the association between vitamin D and OLP from inception to June 2020 on scientific databases in accordance with PRISMA guidelines. The Newcastle-Ottawa Scale was used to assess the quality of the studies. Statistical analysis of the meta-analysis was performed with Review Manager version 5.4. Results: Five case-control studies met the selection criteria. The number of OLP cases ranged from 18 to 102. Finally, 3 case-control studies were eligible for random-effects meta analyses of the mean difference in serum 25-hydroxyvitamin D concentrations between OLP cases and controls using inverse-variance method. The pooled mean difference in random-effects meta-analysis was 5.98 and this difefrence did not reach statistical significance. Conclusions: The current meta-analysis showed numerically lower vitamin D level in patients with OLP, which was statistically non-significant. Keywords: Vitamin D, oral lichen planus, calcitriol, 25(OH)D, autoimmune disease