Predictive roles of oral and mental health among Korean older adults experiencing functional cognitive impairment: A secondary data analysis from the 2019 Community Health Survey

South Korea is undergoing rapid demographic aging, and the health of older adults has become a national priority. Experiencing aging-related cognitive impairment decreases the quality of life for older adults. Therefore, the purpose of this study was to investigate factors affecting cognitive impairment and to establish intervention strategies to reduce its incidence. This descriptive survey study investigated general characteristics, mental health factors (depression, stress, sleep), and oral health factors (toothbrushing frequency, chewing discomfort, oral health status) affecting cognitive dysfunction in older adult South Koreans. A secondary analysis was conducted using data from the 2019 Community Health Survey, carried out by the Korea Disease Control and Prevention Agency. Among the 74,231 older adults (aged 64 years or older) in the dataset, 21,694 individuals experiencing cognitive impairment were 1st selected, and among these, complex sample binomial logistic regression analysis was used to examine the 4898 individuals with functional cognitive impairment (FCI). The risk of FCI increased 1.24-fold for participants with depression (OR = 1.24, 95% CI: 1.23-1.25), 0.73-fold for participants with higher stress (OR = 0.73, 95% CI: 0.67-0.81), and 1.65-fold for participants with poor oral health status (OR = 1.65, 95% CI: 1.48-1.83). FCI risk increased for participants with inadequate physical activity levels (OR = 0.56, 95% CI: 0.50-0.62), hypertension (OR = 1.11, 95% CI: 1.03-1.21), and diabetes (OR = 0.89, 95% CI: 0.81-0.98). In particular, FCI risk increased 1.61-fold among unemployed participants (OR = 1.61, 95% CI: 1.46-1.78) and 1.55-fold among those with low educational attainment (OR = 1.55, 95% CI: 1.36-1.77). Effective reduction of cognitive impairment among older adults in South Korea requires integrated management of mental and oral health, alongside active support for their socioeconomic participation.