Work ability and health-related productivity loss by chronotype: Results from population-based panel study

Abstract

Objectives: This study aimed to explore the relationship between chronotype and two key occupational health outcomes-work ability and health-related productivity loss-in the general working population of Korea. The research further sought to identify subgroup variations by demographic and occupational factors.

Methods: Data were derived from the Korean Work, Sleep, and Health Study (KWSHS), a nationwide panel study conducted between 2022 and 2024. Chronotype was assessed using the reduced Morningness-Eveningness Questionnaire (rMEQ), categorizing participants as morning, intermediate, or evening types. Work ability and health-related productivity loss were measured using the Work Ability Index (WAI) and the Work Productivity and Activity Impairment Questionnaire (WPAI), respectively. Generalized estimating equation models were employed to estimate odds ratios for poor work ability and mean differences in health-related productivity loss, adjusting for demographic and occupational factors.

Results: Evening chronotypes exhibited significantly higher odds of poor work ability (adjusted odds ratio: 2.291, 95% CI: 1.717-3.058) and greater health-related productivity loss (mean difference: 5.362%, 95% CI: 3.902-6.822) compared to morning types. Intermediate types demonstrated moderately elevated risks. Subgroup analyses revealed that evening-type men, younger workers, and white-collar employees experienced the greatest disparities. Conversely, the impact of chronotype on shift workers was less pronounced.

Conclusions: Chronotype significantly influences work ability and health-related productivity loss, with evening types experiencing the poorest outcomes due to circadian misalignment. These findings suggest the importance of considering chronotype in workplace health interventions. Strategies such as flexible schedules and sleep health programs may mitigate productivity losses and enhance employees' well-being.

Keywords: Chronotype; Circadian misalignment; Occupational health; Productivity loss; Social jetlag; Work ability.