Oral health and risk of colorectal cancer: results from three cohort studies and a meta-analysis

BackgroundWhile studies have shown that poor oral health status may increase the risk of cancer, evidence of a specific association with the risk of colorectal cancer (CRC) is inconclusive. We evaluated the association between oral health and CRC risk using data from three large cohorts: the Shanghai Men's Health Study (SMHS), the Shanghai Women's Health Study (SWHS), and the Southern Community Cohort Study (SCCS), and carried out a meta-analysis of results from other relevant published studies.Patients and methodsThis study applied a nested case–control study design and included 825 cases/3298 controls from the SMHS/SWHS and 238 cases/2258 controls from the SCCS. The association between oral health status (i.e. tooth loss/tooth decay) and CRC risk was assessed using conditional logistic regression models. A meta-analysis was carried out based on results from the present study and three published studies.ResultsWe found that tooth loss was not associated with increased risk of CRC. ORs and respective 95% CIs associated with loss of 1–5, 6–10, and >10 teeth compared with those with full teeth are 0.87 (0.69–1.10), 0.93 (0.70–1.24), and 0.85 (0.66–1.11) among SMHS/SWHS participants; and 1.13 (0.72–1.79), 0.87 (0.52–1.43), and 1.00 (0.63–1.58) for those with loss of 1–4, 5–10, and >10 teeth among SCCS participants. Data regarding tooth decay were available in the SCCS, but were not associated with CRC risk. Meta-analysis confirmed the null association between tooth loss/periodontal disease and CRC risk (OR 1.05, 95% CI 0.86–1.29).ConclusionIn this analysis of three cohorts and a meta-analysis, we found no evidence supporting an association between oral health and CRC risk.