Association between missing teeth number and all-cause and cardiovascular mortality: NHANES 1999-2004 and 2009-2014

Background: The association between tooth loss and all-cause and cardiovascular mortality requires further investigation.Methods: This study included 17993 participants from the National Health and Nutrition Examination Surveys (NHANES) 1999-2004 and 2009-2014. Weighted multivariable Cox proportional hazard models were used to assess the association between tooth loss and all-cause and cardiovascular mortality. Restricted cubic splines (RCS) were incorporated in the models to explore potential nonlinear relationships.Results: Over a median follow-up of 116 months, 2152 participants died, including 625 cardiovascular deaths. Compared to participants without missing teeth, participants with 11-19 missing teeth had the highest risk of all-cause mortality (hazard ratio [HR] 1.89, 95% confidence interval [CI] 1.43-2.51), while participants with 6-10 missing teeth had the highest risk of cardiovascular mortality (HR 2.51, 95% CI 1.68-3.76). RCS analyses revealed nonlinear associations between number of missing teeth and all-cause (p < 0.001) and cardiovascular (p = 0.001) mortality. With < 10 missing teeth, each additional missing tooth increased all-cause and cardiovascular mortality by 6% (HR 1.06, 95% CI 1.03-1.09) and 9% (HR 1.09, 95% CI 1.03-1.15), respectively. However, when the number of missing teeth was >= 10, the risk of mortality did not continue to increase with more missing teeth. A significant interaction was found between tooth loss and age (p < 0.001 for both outcomes).Conclusion: We observed an inverted L-shaped association between tooth loss and mortality, wherein risks increased with more missing teeth until 10, but did not continue increasing thereafter. The association was stronger in adults < 65 years old.