Association of oral disease with cancer incidence and mortality among adults in South Korea: A nationwide retrospective cohort study

<b>Objectives:</b> While studies have begun to suggest a potential link between periodontal disease and cancer, there remains a paucity of comprehensive investigations into its association with specific cancer incidence and mortality. This study aimed to analyze association between three oral diseases and site-specific cancer incidence and mortality. <b>Methods:</b> A retrospective cohort study was conducted on a population of 3,845,280, utilizing data sourced from the Korean National Health Insurance Database from 2006 to 2019, supplemented by National Statistics Data from 2010 to 2019. Cox proportional hazards models were applied to estimate the association between oral disease (dental caries, gingivitis, and tooth loss) and site-specific cancer risk of incidence and mortality. <b>Results:</b> After a median follow up of 10.11 years, we identified 181,754 new cancer cases and 37,135 deaths from cancer. Tooth loss was significantly associated with stomach cancer (adjusted hazard ratio (aHR): 1.08, 95% confidence interval (CI): 1.05-1.11), colorectal cancer (1.13, 1.09-1.16), liver cancer (1.09, 1.04-1.14), and lung cancer (1.04, 1.01-1.08) incidences. Tooth loss was significantly associated with mortality for total cancer (1.12, 1.09-1.14), stomach cancer (1.21, 1.12-1.31), colorectal cancer (1.14, 1.05-1.23), liver cancer (1.16, 1.09-1.23), lung cancer (1.08, 1.03-1.13), and prostate cancer (1.24, 1.04-1.47) mortality. Gingivitis was significantly associated with liver cancer incidence and mortality (1.08, 1.03-1.13; 1.11, 1.05-1.18). <b>Conclusions:</b> The results of this study showed that not only tooth loss but also gingivitis, an early stage of periodontal disease, may increase the risk of cancer incidence and mortality. Improving oral health can be prioritized to enhance overall public health, including reducing the risk of cancer.