SERUM LACTATE DEHYDROGENASE DYNAMICS IN TOBACCO USERS AND TOBACCO-ASSOCIATED ORAL POTENTIALLY MALIGNANT DISORDERS: A BIOMARKER-BASED COMPARATIVE STUDY

Abstract

Background: Oral potentially malignant disorders (OPMDs), particularly oral leukoplakia and oral submucous fibrosis (OSMF), are associated with an increased risk of malignant transformation. Lactate dehydrogenase (LDH), an intracellular glycolytic enzyme released during cellular injury and increased metabolic activity, has emerged as a potential biomarker for the early detection and monitoring of these lesions. This study compared serum LDH levels among healthy individuals, tobacco users without oral lesions, and patients with tobacco-associated OPMDs, and evaluated their association with lesion severity. Materials and Methods: A cross-sectional comparative study included 45 participants aged 30–45 years, equally divided into three groups (n = 15 each): healthy controls, tobacco users without oral lesions, and tobacco users with clinically diagnosed OPMDs. The OPMD group comprised nine patients with OSMF and six with oral leukoplakia. Venous blood (5 mL) was collected, and serum LDH levels were measured using an automated biochemical analyser. Statistical analysis was performed using IBM SPSS Statistics version 20.0, with p < 0.05 considered statistically significant. Results: Serum LDH levels were significantly higher in tobacco users than in healthy controls (p = 0.013) and were further elevated, though not significantly, in patients with OPMDs compared with tobacco users without lesions (p = 0.098). Within the OPMD group, Grade II OSMF showed significantly higher serum LDH levels than Grade I OSMF. Similarly, speckled leukoplakia demonstrated higher LDH levels than homogeneous leukoplakia, indicating a positive association between serum LDH levels and lesion severity. Conclusion: Serum LDH levels increased progressively from healthy individuals to tobacco users and were highest in patients with tobacco-associated OPMDs. These findings suggest that serum LDH may serve as a simple, inexpensive, and minimally invasive biomarker for the assessment and monitoring of tobacco-associated OPMDs. Larger longitudinal studies are needed to validate its clinical utility.