Association between swallowing function and oral bacterial flora in independent community-dwelling elderly.

BACKGROUND: Increasing incidences of swallowing dysfunction, or dysphagia, a risk factor for aspiration pneumonia, are being reported in aging populations. AIMS: To investigate the relationship between swallowing function and oral bacteria in independent, community-dwelling elderly. METHODS: This study recruited 139 community-dwelling individuals aged ≥ 70 years with poor swallowing function. The presence of anaerobic (Prevotella spp. and Fusobacterium spp.) and aerobic bacteria was examined in the participants' oral cavity flora. Swallowing function was evaluated using a 30 mL water swallowing test. Multivariate logistic regression analyses were performed to examine the association between oral bacteria and swallowing function. RESULTS: Swallowing function was assessed as abnormal in 2.9% and as abnormal in 47.5% of the subjects. The colony-forming units (CFUs/ml) of Prevotella spp. were associated with the swallowing dysfunction (odds ratio [OR] 3.45, 95% confidence interval [CI] 1.49-8.11). Further, CFUs/ml of Fusobacterium spp. and aerobes did not correlate with the swallowing dysfunction but were related with the number of teeth (OR 2.71; 95% CI 1.28-5.74, and OR 0.40; 95% CI, 0.18-0.91, respectively) CONCLUSIONS: Swallowing dysfunction in community-dwelling elderly is associated with increased abundance of Prevotella spp., which indirectly may be an increased risk factor for aspiration pneumonia.