Functional Dentition, Dietary Fiber Intake and Risk of Colorectal Cancers: Results from a Canadian Study

Objectives: To estimate the extent to which functional dentition (FD) is associated with an increased risk of colorectal cancer (CRC).
Methods: We used data from a population-based case-control study conducted in the Montreal area, Canada. Cases (305) with new, histologically-confirmed CRC were ascertained across 5 major hospitals in 2013-2019. Non-cancer controls (298) were randomly selected from the Quebec Electoral Office lists and frequency matched to cases by age and sex. Interviews collected information on an array of exposures including sociodemographic and behavioural factors (e.g., oral health, diet, smoking). We measured FD using number of pairs of posterior teeth in contact with each other, and high dietary fiber consumption as more than 2-3 portions of fruits/vegetables per day. We used logistic regression to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the association between FD and CRC.
Results: Cases had worse FD compared to controls. Having nine pairs of teeth in contact or more was associated with a decreased risk of CRC (OR=0.52; 95%CI: 0.31-0.86). This association remained after adjusting for high dietary fiber intake (OR=0.52; 95% CI: 0.32-0.89). Interestingly, stratifying by dietary fiber consumption levels, this association remained in the low dietary fiber consumption group (OR=0.55; 95%CI: 0.33-0.93). However, in the high fiber consumer group the association decreased (OR=0.12; 95% CI: 0.01-2.00).
Conclusions: Our preliminary results suggest that the association between FD measured by the number of pairs of posterior teeth in contact and CRC may be modified or mediated by dietary fiber intake.