Interrelationships between education, occupational class and income as determinants of sickness absence among young employees in 2002-2007 and 2008-2013

Background: A low socioeconomic position (SEP) is consistently associated with ill health, sickness absence (SA) and permanent disability, but studies among young employees are lacking. We examined the interrelationships between education, occupational class and income as determinants of SA among 25-34-year-old employees. We also examined, whether the association between SEP and SA varied over time in 2002-2007 and 2008-2013. Methods: The analyses covered young, 25-34-year-old women and men employed by the City of Helsinki over the time periods 2002-2007 and 2008-2013. Four-level education and occupational class classifications were used, as well as income quartiles. The outcome measure was the number of annual SA days. Results: Education had the strongest and most consistent independent association with SA among women and men in both periods under study. Occupational class had weaker independent and less consistent association with SA. Income had an independent association with SA, which strengthened over time among the men. The interrelationships between the SEP indicators and SA were partly explained by prior or mediated through subsequent SEP indicators. Socioeconomic differences followed only partially a gradient for occupational class and also for income among men. Conclusions: Preventive measures to reduce the risk of SA should be considered, especially among young employees with a basic or lower-secondary education.