Association of periodontitis with incidence of metabolic syndrome in Korea: A retrospective cohort study

BACKGROUND: Although periodontitis has been linked to systemic conditions such as metabolic syndrome, longitudinal evidence remains limited. This nationwide population-based cohort study aimed to investigate whether periodontal status is associated with the incidence of metabolic syndrome in Korea. METHODS: We analyzed data obtained from the National Health Insurance Service-Health Screening cohort (2009-2019), including 43,713 participants aged ≥40 years. Periodontitis was assessed using diagnostic codes and periodontal treatment procedures. Metabolic syndrome was defined based on the modified National Cholesterol Education Program Adult Treatment Panel III criteria. This longitudinal cohort analysis used Cox proportional hazards models to examine the association between baseline periodontitis and the subsequent incidence of metabolic syndrome. RESULTS: During the 9-year follow-up, individuals with severe periodontitis had a significantly elevated risk of developing metabolic syndrome compared with those without periodontitis (hazard ratio [HR] = 1.10; 95% confidence interval [CI]: 1.05-1.16). The association was particularly pronounced in individuals aged 50-59 years (HR = 1.16; 95% CI: 1.10-1.23), indicating a significant interaction between age and periodontal severity (p for interaction = 0.015). CONCLUSIONS: These findings suggest that oral inflammatory conditions may be implicated in metabolic health, with the strength of the association varying by age. Thus, age-specific vulnerability should be considered when developing preventive strategies.