Perceived Masticatory Function and Mortality: A Causal Study

Masticatory function has been implicated in overall health decline, making it a potential target for public health interventions. We aimed 1) to assess whether perceived masticatory function is associated with all-cause mortality and 2) to quantify the impact of perceived masticatory function on all-cause mortality with a doubly robust causal inference approach. Data from a nationally representative longitudinal study of older people in Singapore were utilized. Perceived masticatory function was treated as a time-varying exposure (measured at the first 2 time points). It was categorized into 6 groups, ranging from group 1 (able to chew the toughest foods) to group 6 (unable to chew even the softest foods), reflecting increasing levels of chewing difficulty. All-cause mortality information until December 31, 2015, was assessed. Multivariable Cox regression models assessed the association between perceived masticatory function and all-cause mortality. Then, the longitudinal modified treatment policies approach was applied to estimate the effect of hypothetical preventive scenarios to preserve perceived masticatory function on mortality over 6 y. A total of 4,990 individuals were included in the analysis. The mean age at baseline was 72.8 y (SD, 8.1). For each level decrease in perceived masticatory function, the hazard ratio was 1.09 (95% CI, 1.05 to 1.14; P < 0.05). When perceived masticatory function was dichotomized into a binary variable with group 1 (no chewing difficulty) vs groups 2 to 6 (any level of difficulty), the hazard ratio was 1.25 (95% CI, 1.10 to 1.43; P < 0.05). The best hypothetical preventive scenario where all participants preserved maximum perceived masticatory function throughout the follow-up increased survival probability by 3% (relative risk, 1.03; 95% CI, 1.01 to 1.05; P < 0.05). Increased perceived masticatory function is associated and causally linked with reduced all-cause mortality among older adults in an Asian population. Policies aimed at preserving perceived masticatory function may be beneficial for older people's longer life spans and healthy life expectancy.