Evaluating the Association Between Risk Factors of Obstructive Sleep Apnea with Oral Dysfunction and Lifestyle Behavior in Korean Adults Using Data from the Eighth Cycle of the National Health and Nutrition Examination Survey: A Cross-Sectional Study

<b>Background/Objectives</b>: Research on oral dysfunctions as contributing factors to obstructive sleep apnea (OSA) is needed to prevent and treat OSA. This study aimed to explore the association of OSA with oral dysfunction and examine its impact on nutrient intake, physical activity, and handgrip strength. <b>Methods</b>: This cross-sectional study analyzed data from the Eighth cycle Korea National Health and Nutrition Examination Survey (KNHANES, 2019-2021). The OSA group included diagnosed individuals and those over 40 years with symptoms such as snoring, fatigue, or witnessed breathing pauses during sleep. The non-OSA group included individuals not meeting these criteria. Using 1:1 propensity score matching to control for confounders (sex, age, lifestyle factors), 7636 participants were included. Oral dysfunction was assessed based on chewing problems, complaints of chewing discomfort, and speech difficulties. Nutrient intake, physical activity, and handgrip strength were analyzed using the Rao-Scott χ² test, complex sample <i>t</i>-test, and complex sample logistic regression. <b>Results</b>: The OSA group demonstrated significantly more oral dysfunction elements than the non-OSA group (<i>p</i> < 0.001). Higher energy intake was observed in the OSA group, with no significant differences in macronutrient intake. Physical activity levels were similar between groups; however, OSA participants without oral problems had higher handgrip strength (<i>p</i> < 0.05). Regression analysis showed increased OSA risk correlated with greater oral dysfunction and lower protein intake. <b>Conclusions</b>: This study revealed a strong association between oral dysfunction and OSA risk. Focusing on the assessment and early intervention of oral dysfunctions that influence OSA risk factors may aid in the early detection and prevention of OSA.