Masticatory function, inflammation, and mortality after stroke: A prospective cohort study

This study aimed to clarify the relationship between masticatory function and mortality (both all-cause and cardiovascular) in stroke patients and explore the potential mediating role of systemic inflammation. This study utilized data from the National Health and Nutrition Examination Survey cycles spanning 1999 to 2018, comprising 1708 participants aged 20 or older with a history of stroke. Mortality was tracked through December 31, 2018. Masticatory function was assessed based on the count of functional tooth units (FTUs). The associations between masticatory function and all-cause and cardiovascular mortality were evaluated using Cox regression model and subgroup analysis. Mediation analysis was further performed to assess the potential mediating effects of the systemic inflammatory biomarkers, namely the aggregate index of systemic inflammation and the systemic inflammation response index, in the relationship between masticatory function and mortality. Stroke participants with a greater number of FTUs exhibited lower all-cause and cardiovascular mortality. Cox regression model revealed that FTUs were inversely associated with all-cause mortality (hazard ratio = 0.73, 95% confidence interval = 0.57-0.93) but not significantly associated with cardiovascular mortality (hazard ratio = 0.80, 95% confidence interval = 0.54-1.18). Mediation analysis indicated that aggregate index of systemic inflammation and systemic inflammation response index mediated 3.31% and 6.20%, respectively, of the association between FTUs and all-cause mortality, and 2.17% and 4.27%, respectively, of the association between FTUs and cardiovascular mortality. Improved masticatory function is associated with reduced all-cause and cardiovascular mortality in stroke participants. Furthermore, systemic inflammation appears to partially mediate the association between masticatory function and all-cause mortality. There is stronger and consistent evidence for an association with all-cause mortality than with cardiovascular mortality. These findings suggest that masticatory function may serve as a simple and practical prognostic marker for risk stratification in the stroke population.