Persistent income-related inequalities in cancer screening utilisation in South Korea: Evidence from repeated...

This study aimed to examine trends in income-related inequalities in cancer screening from 2013 to 2023 and decompose these inequalities into contributing factors.

This is a repeated cross-sectional study.

Data were drawn from the 2013, 2018, and 2023 waves of the nationally representative cross-sectional Korea National Health and Nutrition Examination Survey. Screening uptake was defined as having received any cancer screening within the past two years, reflecting Korea's biennial check-up schedule. Income-related inequality was assessed using the Erreygers concentration index (ECI) and the horizontal inequity index (HIwv). The ECI was decomposed to identify contributing factors.

Screening rates increased across all income groups, with overall participation rising from 63.7 % in 2013 to 71.8 % in 2023. However, a widening pro-rich inequality was observed over this period. The ECI rose from 0.127 (standard error [SE]: 0.018) in 2013 to 0.149 (SE: 0.016) in 2023, and the HIwv increased from 0.108 (SE: 0.019) to 0.146 (SE: 0.016). Income and private health insurance (PHI) made the largest contributions. Income's share of inequality nearly doubled from 38.2 % to 71.4 %, while PHI's declined from 35.8 % to 24.9 %.

Despite near-universal financial coverage, persistent pro-rich inequalities in cancer screening suggest that eliminating direct screening costs alone is insufficient to achieve equity. Broader strategies addressing structural and social barriers - including post-diagnosis financial concerns, time constraints, and gaps in education and health literacy - are required to ensure equitable access to preventive care.