Domain‐Specific Oral Hypofunction in Older Adults With Obstructive Sleep Apnoea: A Case–Control Study

BACKGROUND: Obstructive sleep apnoea (OSA) has been associated with dysphagia and tongue muscle dysfunction, but its relationship with multidimensional oral hypofunction remains unclear. OBJECTIVES: This study examined whether polysomnography-confirmed OSA is associated with domain-specific oral hypofunction in older adults. METHODS: In this case-control study, adults aged ≥ 50 years were included. OSA was defined as an apnoea-hypopnea index ≥ 5 events/h, while controls were defined as having low OSA risk (STOP-Bang < 3). Oral hypofunction was assessed across seven domains. Sex-stratified analyses and multivariable logistic regression models were performed. RESULTS: A total of 288 participants were included (OSA: n = 69; controls: n = 219). Compared with controls, participants with OSA demonstrated poorer oral hygiene (p < 0.001), greater oral dryness (p = 0.005) and lower tongue pressure (p = 0.022). In contrast, declines in occlusal force and chewing function were more prevalent in controls. Adjusted analyses showed that OSA was independently associated with oral hypofunction (adjusted odds ratio [aOR] = 2.49, 95% CI: 1.07-5.81), poor oral hygiene (aOR = 4.02), oral dryness (aOR = 4.24) and reduced tongue pressure (aOR = 4.95). Similar oral environmental impairments were observed across both sexes, while tongue pressure reduction was more pronounced in males. CONCLUSIONS: OSA is associated with impaired oral environment and reduced tongue pressure. These findings suggest that oral function assessment, particularly tongue pressure measurement, may complement the clinical evaluation of older adults with OSA and help identify individuals at increased risk of swallowing impairment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05977296.