Introduction

Emerging evidence suggests that poor oral health may play a role in gastrointestinal carcinogenesis through inflammatory and microbiome-mediated mechanisms. However, its association with esophageal cancer remains insufficiently explored.

Aims & Methods

We aimed to assess the association of oral health indicators and oral hygiene behaviors with esophageal cancer risk using both dental health screening and claims-based data. We conducted a population-based case-control study using the Korean National Health Insurance Service (NHIS) database and the National Health Screening (NHS) records. To enhance the reliability of our study, we examined oral hygiene from two complementary perspectives: (1) oral health assessed through dental examinations and questionnaires in the NHS database and (2) periodontal disease status determined based on a claim-based analysis of the NHIS database. Individuals newly diagnosed with esophageal cancer were identified and matched at a 1:4 ratio to cancer-free controls through rigorous propensity score (PS) matching based on sociodemographic factors, comorbidities, lifestyle behaviors, and laboratory parameters. Oral health variables were assessed using national dental screening program data (status of decayed, missing, and filled teeth; gingivitis severity; dental calculus; and self-reported oral hygiene practices) and NHIS claims data identifying periodontal disease using ICD-10 codes and procedure codes. Multivariable-adjusted conditional logistic regression analyses were performed to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

Results

After PS matching, the oral health analysis included 4,238 cancer cases and 16,904 controls, while the claim-based periodontal disease analysis comprised 18,905 cancer cases and 75,604 matched controls in the final analysis. In multivariable analysis, missing teeth (adjusted OR, 1.16; 95% CI, 1.08–1.25) and inadequate oral hygiene behaviors—including brushing fewer than three times daily (aOR, 1.14; 95% CI, 1.07–1.23), infrequent toothbrushing before bedtime (aOR, 1.08; 95% CI, 1.00–1.16), infrequent use interdental cleaning tools (aOR, 1.10; 95% CI, 1.01–1.19), and dental visits in the past year (aOR, 1.09; 95% CI, 1.02–1.16)—were significantly associated with an increased risk of esophageal cancer. Additionally, claim-based periodontal disease was independently associated with elevated risk (aOR, 1.05; 95% CI, 1.01–1.09). Subgroup analyses revealed consistent associations across smoking and obesity strata, while sex-, age-, and alcohol-stratified analyses demonstrated differential patterns.

Conclusion

This study provides comprehensive, population-based evidence that both clinically assessed dental health indicators and behavioral oral hygiene practices are associated with esophageal cancer risk. The integration of screening-based and claims-based data enhances the validity of the findings and highlights oral health as a potential modifiable risk factor for esophageal cancer prevention.