Association Between Chewing Capacity and Mortality Risk: The Role of Diet and Ageing

ABSTRACT Aim Masticatory dysfunction due to tooth loss is a potentially modifiable risk for mortality, but the pathway behind that remains to be investigated. This prospective study aimed to examine the role of diet and ageing in the associations between chewing capacity and long‐term mortality. Methods Data were obtained from participants (aged ≥ 20) in the National Health Nutritional and Health Survey (NHANES 1999–2010, n = 22,900). The mortality follow‐up ended on 31 December 2019. Chewing capacity was determined by the number of functional tooth units (FTUs). Diet information in NHANES was collected using a 24‐h‐recall questionnaire, and diet quality was measured by three index‐based dietary patterns, namely the nutrition index (NI), energy‐adjusted dietary inflammatory index (E‐DII) and healthy eating index‐2015 (HEI‐2015). The biological ageing process was reflected using phenotypic age acceleration (PhenoAgeAccel) and frailty index. Mediation analyses were conducted to assess the role of diet quality in the association between FTUs and ageing, as well as the role of ageing in the association between impaired chewing capacity (ICC) and mortality. Results Participants with more FTUs were found to have a slower biological ageing process. Diet quality scores were estimated to mediate 9.0%–23.0% of the association between chewing capacity and biological ageing. Multivariable Cox proportional hazards regression models found a positive association between ICC and all‐cause mortality (hazard ratio = 1.282 [95% confidence interval: 1.189–1.382]). Also, ICC was significantly associated with a 28.9% higher risk of mortality due to cardiovascular disease (CVD) and a 32.7% higher risk of mortality due to cancer. Mediation analyses indicated that PhenoAgeAccel mediated the effect of ICC on all‐cause, CVD and cancer mortality with proportions of 18.1%, 17.3% and 12.5%, respectively. Similar mediating proportions were observed in the frailty index (range: 11.6%–23.5%). Conclusions ICC was associated with poorer diet quality and accelerated ageing, resulting in higher mortality risk. Therefore, it is plausible that dietary interventions and oral rehabilitation would promote healthy longevity, although further investigations are needed.