Bidirectional association between chronic periodontitis and bronchiectasis: A nationwide, population-based cohort study

Background: This study investigated the potential bidirectional association between chronic periodontitis (CP) and bronchiectasis using the Korean National Health Insurance Service claims database. Methods: In study I, individuals with CP (n = 54,535) were matched to those without CP, and in study II, individuals with bronchiectasis (n = 2804) were matched to those without bronchiectasis, using 1:1 propensity score matching. Individuals were followed until the date of bronchiectasis diagnosis (study I), the date of CP diagnosis (study II), death, or December 31, 2019, whichever came first. Results: In study I, during a median follow-up of 11.8 years, 4.25% of the CP group and 0.77% of the control group developed bronchiectasis. The risk of developing bronchiectasis was significantly higher in the CP group compared to the matched controls (hazard ratio [HR] 3.35; 95% confidence interval [CI] 3.02–3.73). In study II, the risk of CP was also higher in the bronchiectasis group compared with matched controls (HR 1.07; 95% CI 1.01–1.15). Conclusion: CP and bronchiectasis were bidirectionally associated, although CP had a stronger impact on bronchiectasis risk than the reverse association.