Occupational class differences in daily sitting time among young and early midlife public sector employees-a...

Longitudinal and domain-specific changes in sitting time (ST) across occupational classes are poorly understood. We examined changes in occupational class differences in total and domain-specific ST over a 5-year follow-up among young and early midlife employees. We used Helsinki Health Study survey data from 2017 to 2022 (n = 2762; 81% women; aged 19-39 years). Self-reported ST (min/day) was assessed across total ST and its five subdomains (work, leisure screen time, reading, transport, and other). Occupational class was categorized as manual and routine non-manual, semi-professional, and professional. Linear mixed models were used to estimate changes, with ST as the dependent variable and time, occupational class, and their interaction as the main independent variables. Analyses were stratified by gender and adjusted for sociodemographic and health-related factors. Total ST increased across occupational classes (+46 min/day, 95% CI: 37.6-54.4), driven by work-related ST (+24 min), and leisure screen ST (+21 min). Among women, manual and routine non-manual employees showed larger increases in total ST (+25 min vs. professionals) and leisure screen ST (+14 min), narrowing the total ST but widening screen time occupational class differences. Semi-professional women increased work ST (+21 min vs. professionals), narrowing occupational class differences in work ST. Among men, statistical significance of the associations could not be confirmed. ST increased across occupational classes, with domain-specific changes suggesting behavioural patterns. Increase in leisure screen time among manual and routine non-manual women employees may contribute to socioeconomic inequalities in health, highlighting the need for targeted, domain-specific interventions.