Dysphagia and Masticatory Performance as a Mediator of the Xerostomia to Quality of Life Relation in the Older Population: A Structural Equation Model Approach

Abstract Background: The adverse impact of poor oral conditions in older adults on their quality of life is a public health problem. This study assessed the mediating effects of dental status, occlusal condition, dysphagia and masticatory performance on the association between xerostomia and oral health-related quality of life (OHRQoL) in the older population. Methods: A total of 1100 representative community-dwelling adults aged 65 years and older were recruited from a large-scale survey conducted in Kaohsiung, Taiwan. Dental status and occlusal condition were performed by dentists. Information on demographics, physical function, xerostomia, and dysphagia was collected using face-to-face interview. Masticatory performance was evaluated using color-changeable chewing gum. OHRQoL was measured using Geriatric Oral Health Assessment Index. Results: Comparing with non-xerostomia, participants with xerostomia had a 0.20 decrease in the level of OHRQoL (p< .001), and the direct effect was accounted for 83.3% of the total effect. The dysphagia and the masticatory performance were found to have a significant mediating effect on the association between xerostomia and OHRQoL (βs = 0.20 and −0.13, respectively; βs = 0.05 and −0.08, respectively) and 10.8% of the effect was attributed to dysphagia mediation. Furthermore, the functional teeth and occlusal condition had a significant mediating effect on the association between xerostomia and masticatory performance , and the functional teeth was accounted for 43.6% of the effect. Conclusions: Xerostomia had the greatest effect on OHRQoL. The mediating role of dysphagia and masticatory performance on the association between xerostomia and OHRQoL was significant and deserves further attention. Older adults could improve their OHRQoL through a community-based oral function intervention. Our results further suggest that early screening for swallowing and masticatory function is essential to prevent or delay the onset of complications.