What's not fair about work keeps me up: Perceived unfairness about work impairs sleep through negative work-to-family spillover.

This study examined whether perceived unfairness about work was linked to midlife workers' insomnia symptoms over time, and if the association was mediated by negative work-to-family spillover (NWFS). We used 3 waves of longitudinal data across 20 years from the Midlife in the United States Study (N = 971, Mage = 40.52). Results revealed that, wave-to-wave increases in perceived unfairness about work predicted wave-to-wave increases in NWFS over 20 years. Wave-to-wave increases in NWFS, in turn, predicted wave-to-wave increases in insomnia symptoms. Perceived unfairness about work was indirectly, but not directly associated with insomnia symptoms through NWFS. These within-person indirect mediation pathways were found after controlling for sociodemographic and family characteristics, work hours, neuroticism, physical health, and between-person associations between perceived unfairness about work, NWFS, and insomnia symptoms. These findings suggest that perceived unfairness about work may degrade workers' sleep health over time, through the spillover of work stress to the personal domain.