Relation between number of teeth, malnutrition, and 3‐year mortality in elderly individuals ≥85 years

OBJECTIVE: The number of teeth has been shown to affect mortality. However, it is unclear why the number of teeth is associated with mortality. We focused on the number of teeth and malnutrition and examined whether these differences affect 3‐year all‐cause mortality among very elderly individuals. METHODS: This analysis was conducted using data from the Tokyo Oldest Old Survey on Total Health study. Altogether 513 participants ≥85 years were categorized based on remaining teeth (0, 1–7, 8–18, ≥19). All‐cause mortality was determined by calculating the cumulative 3‐year survival rate according to the remaining number of teeth and the presence/absence of malnutrition. Further, hazard ratios (HRs) were analyzed using Cox regression analyses. RESULTS: No difference was observed according to the number of teeth (p = 0.638), but the presence/absence of malnutrition was significantly associated with mortality (p < 0.001). Malnutrition was independently associated with higher HRs, even after adjusting for confounding factors associated with mortality. (HR: 2.315, 95% CI: 1.431–3.746). Additionally, adjusting for the number of teeth, HR remained significant (HR: 2.365, 95% CI: 1.449–3.853). CONCLUSION: In the very elderly, malnutrition—but not the number of teeth—was independently associated with 3‐year all‐cause mortality after adjusting for various health issues.