Long-term trends and factors associated with migrant participation in Korea's National Health Screening Program: a...

Migrant health is an increasingly important future determinant of population health in Korea due to growing migrant numbers. Preventive care inequalities affecting migrants may receive limited attention, however because of relative health advantages at their time of arrival and because downstream adverse outcomes may not yet be apparent in this group. In this context, Korea's National Health Screening Program (NHSP), which is largely free at the point of use, provides a valuable window into early disparities in preventive care participation. We aimed to quantify 15-year disparities in Korea's National Health Screening Program (NHSP) participation between migrants and non-migrants, identify associated factors, and assess the persistence of these gaps, even among long-term enrollees after covariate adjustment.

In this retrospective population-based cohort study using linked nationwide administrative data from the Korean National Health Insurance Service and National Health Screening Program records, 1,244,820 migrants and 2,050,771 non-migrants eligible in 2022 were analyzed. Annual participation trends from 2008 to 2022 were examined using crude and age-standardized rates. Multivariable logistic regression among individuals continuously enrolled for ≥ 10 years assessed the independent association of migrant status with ever having undergone screening by 2022.

Age-standardized participation rates were consistently lower among migrants throughout 2008-2022. In 2022, crude participation was 40.3% among migrants and 53.5% among the non-migrant comparison group, whereas age-standardized rates were 31.5% and 38.8%, respectively. Among long-term enrollees, migrants had significantly lower adjusted odds of ever having undergone screening by 2022 (adjusted OR 0.18, 95% CI 0.18-0.19).

Screening participation disparities persisted throughout the study period and remained evident even among migrants continuously enrolled in National Health Insurance for more than a decade. After multivariable adjustment, this disparity was more pronounced than the crude comparisons suggested. In the context of Korea's ongoing demographic change, these findings underscore the importance of early identification and management of migrant screening inequalities. Migrant-tailored, multilingual, and navigation-supported strategies are needed to reduce the risk of preventive care gaps becoming more deeply rooted health inequalities.