Association Between Tooth Loss, Swallowing Function and Cognitive Function in Older Adults in Hong Kong: A Pilot Study

Introduction and aims Tooth loss is a putative risk factor for cognitive decline. However, the underlying mechanisms remain unclear. This study aims to investigate the impact of tooth loss and swallowing function on cognitive function in older adults in Hong Kong. Methods Eighty community-dwelling older adults aged 52 to 87 were included in this study. Participants were classified into three groups based on the number of remaining teeth (RT): complete edentulism, RT < 20, and RT ≥ 20. Cognitive function was assessed using the Montreal Cognitive Assessment Hong Kong Version (HK-MoCA), Digit Span Test (forward, backward, sequencing), Hayling Sentence Completion Test, and One-minute Verbal Fluency Test. Swallowing function was evaluated with a 100 mL Water Swallowing Test and a questionnaire. Statistical analyses (Kruskal–Wallis, one-way ANOVA, Chi-square, backward stepwise regressions, Spearman’s correlation test) were performed. Results Tooth loss was significantly associated with compromised cognitive function (HK-MoCA, P = .001; Digit Span Test-sequencing, P = .003; One-minute Verbal Fluency Test, P = .007) and weakened swallowing ability ( P = .004). However, no significant differences were observed between groups when applying a 10 mL/s cutoff for screening swallowing dysfunction in Water Swallowing Test ( P = .124). Older adults with more tooth loss were more likely to be diagnosed with mild cognitive impairment in HK-MoCA ( P = .037). Degree of tooth loss ( P = .002), education ( P = .016), and reading habits ( P = .039) are significant predictors of cognitive performance. A positive correlation was identified between swallowing and cognitive function ( P = .026). Conclusion This pilot study demonstrated a positive linkage between tooth loss, swallowing function, and cognitive function. However, limited by the small sample size, further studies are warranted to confirm that tooth loss is a predictor for early cognitive and swallowing impairment. Clinical relevance Preserving a functional dentition may prevent dysphagia and mitigate cognitive risks in older populations.