Oral Factors Associated with Swallowing Function in Independent Elders

Purpose: This study clarified the oral factors related to swallowing function using the results of dental check-ups among community-dwelling independent elders. Materials and Methods: Data on oral and medical health check-ups from 4,676 participants aged 75 and 80 years were analysed. Swallowing function was evaluated using the repetitive saliva swallowing test (RSST), which assesses the ability to swallow saliva. Swallowing three or more times during a 30 s period was recorded as normal, while swallowing twice or less in 30 s was considered to indicate swallowing difficulty. Multivariate logistic regression analyses were performed to examine the relationship between oral factors and swallowing function. Results: In all participants, the odds ratio (OR) for swallowing difficulty was 3.42 (95% confidence interval (CI): 1.78–6.55) and 6.68 (95% CI: 1.97–22.64) among those who had 10–19 teeth without dentures and those who had 0–9 teeth without dentures, respectively, compared to individuals with ≥ 20 teeth without dentures. Those with moderate or severe dry mouth had a statistically significantly higher OR (8.01, 95% CI: 4.84–13.27) for swallowing difficulty than those without dry mouth. Among dentate participants, in addition to statistically significant variables in the analysis among all participants, those with abundant dental plaque showed a significantly higher OR (2.58, 95% CI: 1.54–4.32) for swallowing difficulty compared to those with no or slight dental plaque. Conclusion: These results suggest that oral factors such as having few teeth without dentures, dry mouth, and poor oral hygiene are related to swallowing function in elders. Keywords: swallowing function, tooth, dentures, xerostomia