Oral health and gastrointestinal cancer: A nationwide cohort study.

AIMS: Poor oral hygiene is closely associated with bacteraemia and systemic inflammation, which are known mediators of cancer development. We investigated the relationship between oral hygiene indicators and the risk of gastrointestinal cancer in a nationwide population-based cohort. MATERIALS AND METHODS: This study was conducted on data from 150,774 subjects from the Korean National Health Screening Cohort. The occurrence of gastrointestinal cancer was analysed according to the presence of periodontal disease and oral hygiene indicators: frequency of toothbrushing, dental visits for any reason, professional dental cleanings and number of missing teeth. Gastrointestinal cancer was defined using International Statistical Classification of Diseases-10 codes C15-C26. RESULTS: During a median 11.6 years of follow-up, the estimated 10-year event rate for gastrointestinal cancer was 6.76%. In a multivariable analysis, after adjusting for age, sex, income level, regular exercise, alcohol consumption, smoking status, body mass index, history of comorbidities, systolic blood pressure and laboratory findings, frequent toothbrushing (≥3/day) was significantly associated with a reduced risk for gastrointestinal cancer (hazard ratio: 0.91, 95% confidence interval (0.86-0.96), p < .001, p for trend < .001). CONCLUSIONS: Good oral hygiene behaviour, especially frequent toothbrushing, could be associated with a lower risk of gastrointestinal cancer.