Background: The relationship between socioeconomic status and risk of coronavirus disease (COVID-19) remains controversial. We aimed to investigate whether socioeconomic status affected the risk of COVID-19 in the South Korean population.Methods: The NHIS-COVID-19 database cohort was used in this population-based study. We collected data of COVID-19 patients who were diagnosed between January 1, 2020 and June 26, 2020 and those of the control population. The income levels of all individuals as of February 2020 were extracted and classified into four groups based on quartile ratios: Q1 (the lowest) to Q4 (the highest).Findings: In total, 122,040 individuals—7,669 and 114,371 in the COVID-19 and control populations, respectively—were included in the final analysis. Multivariable logistic regression model showed that the Q1 group had a 1.19-fold higher risk of COVID-19 than the Q4 group, whereas the Q2 and Q3 groups showed no significant differences. In the 20-39-year-old group, compared with the Q4 group, the Q3 and Q2 groups showed 11% and 22% lower risks of COVID-19, respectively. In the ≥60-year-old group, compared with the Q4 group, the Q1, Q2, and Q3 groups showed 1.39-fold, 1.29-fold, and 1.14-fold higher risks of COVID-19, respectively.Interpretation: Lower socioeconomic status was associated with a higher risk of contracting COVID-19 in South Korea. This association was more evident in the older population (≥60-year-old), whereas both lower and higher socioeconomic status were associated with higher risks of contracting COVID-19 in the young adult population (20-39-year-old). Funding: NoneDeclaration of Interests: None declared.Ethics Approval Statement: The study protocol was approved by the Institutional Review Board of Seoul National University Bundang Hospital (X-2004-604-905) and the Health Insurance Review and Assessment Service (NHIS-2020-1- 291). Informed consent was waived because the data analyses were performed retrospectively using anonymized data derived from the South Korean NHIS database.
Socioeconomic Disparity and Risk of COVID-19 in South Korea: An NHIS-COVID-19 Database Cohort Study