Masticatory dysfunction may impact metabolic health. However, the associations between functional tooth units (FTUs)—a quantitative measure of chewing ability—and metabolic syndrome (MetS) or mortality risk remain unclear. This study used data from NHANES 1999–2018. A cross-sectional design examined the relationship between FTUs and MetS, while a prospective cohort design assessed mortality outcomes. Weighted logistic and Cox regression models were employed to evaluate associations with MetS and all-cause, cardiovascular disease (CVD), and cancer mortality. Restricted cubic splines tested for nonlinear trends. Mediation effects of the Healthy Eating Index-2015 (HEI-2015) and Dietary Inflammatory Index (DII) were assessed via bootstrapping. Sensitivity analysis used tooth loss as an alternative exposure. Time-dependent ROC curves evaluated the predictive performance of FTUs. FTUs were inversely associated with MetS prevalence (P < 0.001), with each standard deviation increase linked to a 13% lower odds of prevalent MetS. In individuals with MetS, FTUs were associated with reduced all-cause (HR = 0.83), CVD (HR = 0.80), and cancer (HR = 0.82) mortality. RCS analyses indicated linear relationships. HEI-2015 and DII mediated 14.96% and 11.94% of the FTU–MetS relationship, respectively. FTUs showed improved mortality prediction over time (AUC up to 0.81). Findings were robust in sensitivity analyses. FTUs are associated with MetS and mortality risk, partly mediated by diet quality. FTUs may be a valuable oral health marker for assessing metabolic status and long-term health risks.
Jia et al. (Thu,) studied this question.