Association Between Kihon Checklist Oral‐Function Score and All‐Cause Mortality in Community‐Dwelling Older Adults

Background We examined whether the Kihon Checklist (KCL) oral‐function score (0–3), based on three self‐reported symptoms (chewing difficulty, dysphagia, and xerostomia), was associated with all‐cause mortality in community‐dwelling older adults. Methods This cohort study included 52,789 adults aged ≥ 65 years who underwent municipal health checkups in Okayama City, Japan (fiscal year 2006–2007) with mortality follow‐ups during December 2016. The KCL oral‐function score (range 0–3) was the sum of the positive responses to the three oral‐function items. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHR). Secondary analysis examined the association of each symptom using separate and mutually adjusted models. Results Higher KCL oral‐function scores were positively associated with increased all‐cause mortality. In the fully adjusted model ( n = 49,665), the aHRs (95% confidence interval [CI]) for scores 1, 2, and 3 were 1.09 (1.04–1.13), 1.26 (1.20–1.32), and 1.49 (1.38–1.60), respectively. Chewing difficulty (aHR 1.19 [95% CI 1.14–1.23]) and dysphagia (aHR 1.18 [95% CI 1.14–1.23]) were each independently associated with mortality, whereas xerostomia was not (aHR 1.02 [95% CI 0.98–1.06]). Conclusions Higher KCL oral‐function scores showed a positive association with all‐cause mortality. Chewing difficulty and dysphagia were independently associated with mortality, whereas xerostomia was not. Symptom‐based oral‐function screening may help identify older adults at an elevated mortality risk.