Paradox of long working hours: how income levels and satisfaction modify health outcomes

This study investigates how household income levels and satisfaction with income impact the relationship between long working hours and self-rated health (SRH) among Korean workers. We analysed data from the Korean Labour & Income Panel Study spanning 2018 to 2022, including 8,954 to 10,079 wage workers annually. Weekly working hours and SRH were the primary variables, with equivalized household income levels classified into quartiles. A generalised estimating equation was used to assess the relationship between long working hours and poor SRH, adjusted for demographic and health-related factors. Subgroup analyses were conducted based on household income level and satisfaction. Long working hours were generally associated with poor SRH (OR 1.30, 95% CI 1.10–1.54) in unadjusted model, particularly among higher-income groups (OR 1.46, 95% CI 1.05–2.01 for Q4) after adjustment for covariates. However, no significant association was found for lower-income groups. When stratified by income satisfaction, longer working hours were significantly associated with poor SRH only in income-satisfied individuals among higher-income group. The health effects of long working hours may differ according to household income levels and satisfaction. Policy interventions should consider both work hour reductions and income adequacy to improve worker health.