Exploring the association between diabetes and oral lichen planus: A systematic review

Persistent inflammatory oral mucosal lesions characteristic of oral lichen planus (OLP) have attracted considerable attention due to their potential association with diabetes mellitus (DM). This systematic review aimed to synthesize evidence from different study designs, including cross-sectional and case-control studies, to clarify the complex relationship between OLP and DM. The study was conducted according to predefined objectives and eligibility criteria. Using the PECOS framework, the review evaluated the prevalence, risk factors and comorbidities associated with DM among individuals with clinically diagnosed OLP. A search strategy combining Medical Subject Heading (MeSH) terms and relevant keywords was applied across multiple databases. The findings demonstrated variability in the reported prevalence and clinical associations between type 2 DM (T2DM) and OLP. Some studies reported a strong correlation, whereas others yielded conflicting findings, potentially reflecting methodological differences. Cross-sectional studies generally demonstrated high methodological quality, supporting the reliability of findings. Case-control studies showed greater variability in methodological quality, with some areas requiring improvement. Quality assessment using the Newcastle-Ottawa Scale (NOS) indicated generally good methodological quality, although differences in selection and comparability were observed across studies. The risk-of-bias assessment identified potential sources of bias, emphasizing the need for cautious interpretation of the available evidence. This study underlines the importance of standardized management procedures, emphasizes individualized patient care and supports further research into the mechanisms underlying the association between OLP and DM.