Association Between Metabolic Syndrome and Risk of Laryngeal Cancer: A Systematic Review

<b>Background</b><b>:</b> Metabolic syndrome (MetS) is a significant global health burden and a known risk factor of cardiovascular disease and diabetes. Growing evidence also links MetS to cancer development, likely via chronic inflammation, insulin resistance, and hormone disruption. However, its association with laryngeal cancer remains largely unclear and underexplored. <b>Methods:</b> For this review, we thoroughly searched PubMed/MEDLINE, Scopus, and Web of Science for observational studies investigating associations of MetS with laryngeal or head and neck cancers (HNCs) until 1 August 2025. Five large population-based studies were found to meet inclusion criteria, and risk of bias was assessed using the Joanna Briggs Institute checklist (JBI). <b>Results:</b> Three Korean cohort studies consistently found that MetS increased the risk of laryngeal cancer (HR 1.13-1.32), independent of smoking and alcohol use. Hypertension and hyperglycemia were the most consistent components associated with increased risk, and chronic MetS conferred the highest hazard. In contrast, analyses from the UK Biobank (HNC) and SEER-Medicare (HNSCC) cohorts showed null and inverse associations, respectively. Additional findings included dose-response effects with increasing MetS components, U-shaped associations for HDL-C and waist circumference and increased risk associated with elevated C-reactive protein. <b>Conclusions:</b> Current evidence suggests a possible association between MetS and risk of laryngeal cancer, although the direction and strength of effect vary across populations. Findings from Korean cohorts provide consistent signals of increased risk, whereas Western datasets have not replicated this pattern. Overall, the certainty of evidence is low to moderate, warranting cautious interpretation and further validation in diverse populations before inferring causality.