Mediating Role of Oral Problems in the Link between Obstructive Sleep Apnea Risk and Hearing Difficulties: A Cross-sectional Study from the Korea National Health and Nutrition Examination Survey 2019–2023

Objective: This study examined the association between obstructive sleep apnea (OSA) risk and hearing difficulty and evaluated whether oral health problems mediate this relationship in a nationally representative Korean population. Methods: We analyzed 15,163 adults aged ≥40 years from the Korea National Health and Nutrition Examination Survey (KNHANES) 2019–2023 datasets. OSA risk was defined using the snoring, tiredness, observed apneas, pressure, body mass index, age, neck circumference, and gender (STOP-BANG) questionnaire (low risk: 0–2; high risk: ≥3). Oral health problems were operationalized as the summed score of self-reported chewing difficulty and speaking difficulty (two 5-point items; range 2–10). Hearing difficulty was assessed using the KNHANES 4-point self-reported hearing scale (1 = no difficulty to 4 = cannot hear at all). Mediation analyses were conducted using complex-sample hierarchical regression with design-weighted estimation, adjusting for survey year, age, sex, education, marital status, income, smoking, alcohol consumption, metabolic/cardiovascular disease comorbidities, occupational noise exposure, and tinnitus. Results: Adults with high-OSA risk had higher weighted mean hearing difficulty scores than the low-risk group (1.23 vs. 1.16). In the adjusted model, OSA risk was associated with hearing difficulty [total effect β = 0.031, 95% confidence interval (CI): 0.013–0.048, P < 0.001]. Oral problems were associated with OSA risk (β = 0.111, 95% CI: 0.049–0.174, P < 0.001) and hearing difficulty (β = 0.014, 95% CI: 0.000–0.027, p = 0.047). The indirect effect was statistically significant (β = 0.001, 95% CI: 0.001–0.002). The direct effect of OSA risk on hearing difficulty remained significant (β = 0.019, 95% CI: 0.011–0.047, P < 0.001). Conclusions: The risk of OSA based on STOP-BANG was associated with increased hearing difficulty among Korean adults, and oral health problems statistically accounted for a small proportion of this cross-sectional association. These results highlight the potential value of jointly considering sleep-related symptoms, oral function, and hearing outcomes in population health research.