Vitamin D is a biomarker of clinical disease severity in oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory condition known to adversely impact patient quality of life and is associated with an increased risk of cancer. The diverse clinical presentation and poor knowledge of clinical factors that determine the course of disease are amongst the main challenges that hinder effective and personalised treatment for OLP patients. This study aimed to systematically identify clinical predictors of disease severity in OLP patients. A cohort of patients with histologically confirmed OLP (n=89) was recruited in a cross-sectional and single site study. A comprehensive assessment of clinical characteristics, medical and social history, haematological parameters, vitamin D levels, and Perceived Stress Scale (PSS-10) was carried out. Hierarchical linear regression identified the predictive value of clinical factors to OLP disease severity measured by the Oral Disease Severity Score (ODSS) and the Reticular/hyperkeratotic, Erosive/erythematous, Ulcerative (REU) scoring system. Findings revealed that extraoral lichen planus and insufficient vitamin D levels were significant predictors of both overall and gingival disease severity of OLP. Specifically, patients with lichen planus affecting the skin or other mucosal sites had a 5.766-unit higher OLP severity score (β=5.766, 95% CI=.744-10.788, p=.025) than those without extraoral involvement as measured by ODSS. Patients with insufficient vitamin D levels exhibited 5.490-unit increase in OLP severity (β=5.490, 95% CI=1.136-9.844, p=.014) compared to those with adequate vitamin D levels. The presence of dental plaque-induced gingivitis (β=4.833, 95% CI=.974-8.692, p=.015), was found to be a significant factor affecting gingival disease severity. This study revealed the importance of adequate vitamin D levels in OLP patients and suggests embedding vitamin D pre-treatment screening to optimise management of OLP. Future research should focus on elucidating the biological mechanisms underlying the protective effects of vitamin D in OLP. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement No external funding was received. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval was obtained from the West Midlands-Black Country Research Ethics Committee (Reference number: 21/WM/0247). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Pseudonymised data can be made available upon reasonable and FAIR-compliant requests to the corresponding author.