Diet-related diseases mediate the effect of masticatory function on premature death in older adults.

Aim: Although poor oral health has been a potentially modifiable risk for mortality, the precise association between functional tooth units (FTUs) and premature death as well as the underlying mechanisms remains unclear.

Methods: This study used data from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. Mortality details were obtained from the National Death Index (NDI). The number of FTUs was defined as pairs of opposing natural and artificial teeth in the premolar and molar area. Weighted logistic regression models were employed to assess the relationship between FTU and premature death. Demographic characteristics, lifestyle habits, and disease histories were adjusted as confounding factors. The propensity score matching (PSM) was conducted to further assess the association between FTU and premature death. Mediation analyses were conducted to assess the role of diet-related diseases in the association between FTU and premature death.

Results: The analysis included 4169 individuals aged between 60 and 74 years. Participants with 0 ≤ FTUs ≤ 3 had a significantly higher odds of premature death compared to the 10 ≤ FTUs ≤ 12 group (OR = 2.142, 95% CI 1.091-4.208). After missing data imputation, 0 ≤ FTUs ≤ 3 was still significantly associated with increased odds of premature death (OR = 2.115, 95% CI 1.125-3.975). The relationship between 0 ≤ FTUs ≤ 3 and reference group persisted (OR = 2.196, 95% CI 1.296-3.721) after PSM analyses. For mechanism, mediation analysis showed that diet-related diseases, including diabetes and hypertension, partially mediated the association between FTU and premature death with proportions of 5.089% and 8.437%, respectively.

Conclusion: The findings revealed a link between impairment of masticatory function and a heightened odds of premature death among older adults. Notably, 0 ≤ FTUs ≤ 3 is significantly correlated to premature death among this demographic, with diabetes and hypertension partially mediating the effect of FTU on premature death. Further longitudinal studies are required to validate the findings.