Educational and sex disparities in trends of health-related work limitations: Evidence from a 20-year age-period-cohort analysis in Korea

OBJECTIVES: As populations age, extending healthy working lives has become a policy priority. However, disparities in health-related work limitations (HRWL) by sex and education attainment persist, and few studies have disentangled their temporal patterns. This study aimed to assess the effects of age, period, and cohort (APC) on HRWL among older Korean adults, over a period of 20 years, using nationally representative panel data stratified by sex and educational attainment. STUDY DESIGN: Population-based longitudinal study. METHODS: We used data from the Korean Labour and Income Panel Study from 2003 to 2023, including 37,019 person-year observations from adults aged 50-85 years. HRWL was defined as the presence of a self-reported health problem that limits one's ability to work, and the outcome variable was work capability (no HRWL). We fitted generalised additive mixed models with an APC specification under a binomial logit link incorporating bivariate smoothing for age and period and a subject-level random intercept. Analyses were stratified by sex and educational level. RESULTS: Later birth cohorts showed lower HRWL, indicating a generational improvement in work capability. Educational disparities were pronounced: higher-educated individuals experienced lower HRWL and greater cohort-related improvements (cohort effect ratio = 355.78), whereas gains were modest among the lower-educated individuals (24.61). Women consistently exhibited higher HRWL than men, although the sex gap has narrowed slightly in recent cohorts. CONCLUSIONS: Our findings indicate a generational improvement in work capability, but these improvements are unequally distributed. Cohort-based health gains are concentrated among highly educated individuals. These findings highlight widening social inequalities in work capacity at older ages.