Association between household income and mental health among adults during the COVID-19 pandemic in Korea: Insights from a community health survey.

People of low socioeconomic status are vulnerable to health problems during disasters such as the COVID-19 pandemic. Using data from the 2019 and 2021 Korea Community Health Survey, this study analyzed the associations between Korean adults' mental health and their national and regional-level household incomes during the pandemic. The prevalence of perceived stress and depression experience for each risk factor category was calculated through univariate analyses. A multivariate logistic regression analysis helped identify the association between two types of income levels (national or regional) and perceived stress and experience of depression. Additionally, we investigated the effect of income levels by subgroup (gender and residential area) on perceived stress and the experience of depression. During the pandemic, the crude prevalence of an experience of depression was higher (6.24% to 7.2%) but that of perceived stress remained unchanged. Regarding regional-income based mental health disparities, even after adjusting for each independent variable, perceived stress (2019 odds ratio (OR): 1.26, 95% confidence interval (CI):1.26-1.27, 2021 OR: 1.32, 95% CI: 1.32-1.32) and experience of depression (2019 OR: 1.56, 95% CI: 1.55-1.56, 2021 OR: 1.63, 95% CI: 1.63-1.64) increased as the income level decreased. The perceived stress based on the two income levels was higher in women than in men. For both income levels, the experience of depression of women was higher than that of men before COVID-19 and vice versa during the COVID-19 period. National income had a more pronounced effect on mental health in urban areas than in rural areas. Contrarily, the effect of regional income level on mental health was not consistent across residential areas (urban and rural areas). Our findings demonstrated that mental health disparities based on income level were more likely to occur during the COVID-19 pandemic and are better reflected through disparities in regional income levels.