Changes in occupational class differences in sedentary time among young and early midlife employees

Abstract Background Limited evidence exists on how sedentary behaviour changes across occupational classes. We examined the changes of between occupational class and changes in sedentary time over a 5-year follow-up among young and early midlife employees. Methods We used data from the Helsinki Health Study follow-up survey among employees of City of Helsinki, Finland, in 2017 (aged 19-39 years) and 2022 (n = 2,762; 81% women). Sedentary time (minutes/day) was assessed across total sitting time and its five subdomains (work, leisure screen time, reading, transport, other). Occupational class was categorized into manual and routine non-manual, semi-professional, and professional. Linear mixed models with fixed effects estimated β-coefficients and 95% confidence intervals (CIs), adjusting for sociodemographic and health-related factors. Results During the 5-year follow-up, daily total sedentary time increased (β = 46 min [95% CI 37.6-54.4]), as did sedentary time during work (β = 24 min [95% CI 18.1-29.7]), leisure screen time (β = 21 min [95% CI 16.2-24.8]), and leisure reading (β = 3 min [95% CI: 0.5-5.5]), whereas sedentary time in transportation decreased (β=-5 min [95% CI -8.5- -1.5]). Women in the lowest occupational class increased total sedentary time (β = 25 min [95% CI 0.1-50.3]) and leisure screen time (β = 14 min [95% CI 0.8-26.6]) compared to those with the highest occupational group, narrowing occupational class differences in total sedentary time and increasing the difference in screen time. Women with the middle occupational group increased their work-related sedentary time (β = 21 min [95% CI 4.4-36.6]), narrowing occupational class differences to the highest occupational class group. Conclusions Sedentary time increased among all participants, with the greatest increases observed in women of the lowest occupational class, particularly in leisure screen time. Our findings raise public health concerns about the growing sedentary behaviours among young and early midlife employees. Key messages • Weekly sedentary time increased by 4 hours over the 5-year follow-up among all employees, with the largest increase among women in lowest occupational class, particularly in leisure screen time. • Reducing sedentary behaviour at work and during leisure is essential to address occupational class-related health disparities.