Abstract
Background: Swallowing dysfunction is a prevalent but often overlooked problem in long-term care facilities. This study investigated the relationships between nutritional deficits, frailty, oral health, and swallowing dysfunction. Additionally, we explored the associations between oral muscle weakness, frailty markers, and swallowing dysfunction. Methods: We recruited 373 participants from seven long-term care facilities across Taiwan. Swallowing function, frailty, nutrition status, and oral health were assessed by research staff. Oral muscle function was evaluated through tongue strength measurements, cheek bulging function tests, the Repetitive Saliva Swallowing Test (RSST), and a diadochokinetic task. Frailty was assessed through grip strength as well as mid-upper arm and calf circumference measurements. Results: The Functional Oral Intake Scale revealed that 97 participants (26%) had swallowing dysfunction. Participants with swallowing dysfunction had poorer nutritional status, higher frailty levels, and worsened oral health. Frailty was the factor most strongly associated with swallowing dysfunction. Participants with swallowing dysfunction also exhibited lower tongue pressure, decreased cheek-bulging ability, fewer repetitions in the diadochokinetic task, lower scores on the RSST, lower calf circumferences, and lower grip strength. Logistic regression demonstrated that cheek bulging was most strongly associated with swallowing dysfunction. Furthermore, lower grip strength was significantly associated with swallowing dysfunction. Conclusions: Frailty was most strongly associated with swallowing dysfunction, followed by poorer nutritional status and worsened oral health. These factors should be thoroughly assessed in long-term care residents. Participants with swallowing dysfunction also experienced oral muscle weakness, particularly in cheek bulging. Grip strength, which represents frailty, was directly associated with swallowing dysfunction and could serve as a crucial indicator of swallowing dysfunction.