Association of Chronic Periodontitis with Migraine in a Korean Adult Population: A Nationwide Nested Case-Control Study

<b>Background:</b> Migraine and chronic periodontitis are prevalent conditions that may share common inflammatory and neurovascular pathways. Growing evidence suggests an association between periodontal inflammation and migraine, yet large-scale population-based studies are limited. <b>Objective:</b> To investigate the association between chronic periodontitis and the occurrence of migraine using a nested case-control design in a nationally representative Korean adult cohort. <b>Methods:</b> This study utilized data from the Korean National Health Insurance Service-Health Screening Cohort (2002-2019). A total of 43,359 individuals diagnosed with migraine (ICD-10: G43) were matched 1:4 by age, sex, income, and residence with 173,436 controls. Chronic periodontitis was identified using ICD-10 code K053. Conditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for demographic, behavioral, and clinical covariates. <b>Results:</b> A significant association was observed between chronic periodontitis and migraine. Individuals with at least one diagnosis of periodontitis within one year prior to migraine onset had increased odds of migraine (adjusted OR = 1.10, 95% CI: 1.08-1.13). Similar associations were observed for two diagnoses within one year (OR = 1.05; 95% CI: 1.01-1.09) and one diagnosis within two years (OR = 1.10; 95% CI: 1.08-1.13). No association was found with three or more diagnoses in one year. Subgroup analyses confirmed consistent associations across migraine subtypes and demographic strata. <b>Conclusions:</b> This study demonstrated a statistically significant association between chronic periodontitis and migraine, suggesting a potential shared inflammatory or neurovascular mechanism. Recognizing periodontal disease as a modifiable factor may offer new insights into migraine prevention and management. Further longitudinal and interventional studies are warranted to establish causality.