Vitamin D is a novel 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 ({beta}=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 ({beta}=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 ({beta}=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.