Periodontal Disease and Incident Chronic Bronchitis: A Nationwide Population-Based Cohort Study

Background/Objectives: Periodontal inflammation has been implicated in respiratory disease, but longitudinal evidence regarding chronic bronchitis (CB) remains limited. This study examined the association between claims-based periodontal status and newly recorded CB in a nationally representative Korean cohort. Methods: This retrospective cohort study used Korean National Health Insurance Service-National Sample Cohort data from 2002 to 2015. Periodontal status was assessed during 2002-2004, and 189,274 adults were followed during 2005-2015. Participants were classified as No PD, Gingivitis (K05.0-K05.1), or Periodontitis-related (K05.2-K05.6). Periodontal treatment was defined as recorded scaling or root planing. Cox models estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Results: During follow-up, 52,955 participants (28.0%) had newly recorded CB. Periodontitis-related diagnoses were associated with a modestly higher CB risk than No PD (aHR = 1.05, 95% CI = 1.02-1.08), whereas Gingivitis was not (aHR = 1.01, 95% CI = 0.99-1.03). The association was observed among adults aged 40-59 years (aHR = 1.06, 95% CI = 1.02-1.11) and those without recorded periodontal treatment (aHR = 1.08, 95% CI = 1.03-1.12). No significant association was observed among treated participants (aHR = 0.86, 95% CI = 0.74-1.01). Conclusions: Periodontitis-related diagnoses were associated with a small increase in newly recorded CB risk, whereas Gingivitis was not. Treatment-stratified findings were exploratory and should not be interpreted as evidence that periodontal treatment prevents CB.