SES and correlated factors do not explain the association between periodontal disease, edentulism, and cancer risk

Purpose: Severe periodontal disease and edentulism have been previously reported to be significantly associated with cancer risk and mortality, including in the Atherosclerosis Risk in Communities study (2018); however, complex sources of confounding by socioeconomic status (SES), and characteristics correlated with SES, could have been present in earlier analyses. Methods: To capture life course SES and its correlates, we generated a propensity score and included it, along with other potential confounders such as smoking and obesity, into a Cox regression model to examine the association between periodontal disease and cancer risk. In addition, we stratified the model with the propensity score by low and high SES. All statistical tests were two-sided. Results: Compared with our previous study, the associations for severe periodontitis and cancer incidence remained comparable after weighting by the propensity score (e.g., for total cancer: before weighting, hazard ratio = 1.24, 95% confidence interval = 1.07–1.42 vs. after weighting, hazard ratio = 1.23, 95% confidence interval = 1.05–1.44 when comparing severe periodontitis to no or mild periodontitis). Associations were comparable in low and high SES strata and statistically significant among participants with high SES. Conclusions: Complex sources of confounding by SES and its correlates are unlikely to fully account for the positive associations observed for periodontal disease and edentulism and cancer risk.