Introduction Low occupational class predicts work disability, but less is known of changes in the cause-specific associations over time or of further variation between industrial sectors. We examined trends in cause-specific sickness absence by occupational class and industrial sector.

Methods We used large representative register data on Finnish wage-earners aged 25–59 years and repeated logistic regression to estimate the annual risk of sickness absence (≥two weeks).

Result Between 2005 and 2013, the proportion of employees with sickness absence decreased. The change was smallest among lower non-manual employees and the overall level highest among manual workers. In musculoskeletal diseases and injuries, the level differences between the occupational classes were particularly large, but decreased over time. In mental disorders, the level was highest among lower non-manual employees with an increasing difference between the occupational classes over time. Among the non-manual classes, the overall absence levels were highest in the health and social work sector. Among manual workers and particularly in musculoskeletal diseases, the level was highest in the manufacturing sector, where a temporary decrease in absences nevertheless occurred during the economic recession in 2009. Among the lower occupational classes, the decreases in absences due to musculoskeletal diseases and/or injury were smallest in the trade sector. Overall, socioeconomic and employment factors, particularly education, income, and employment sector (public vs private), somewhat explained the level differences in sickness absence.

Discussion Particular attention should be paid to both mental and physical work ability among lower non-manual employees in the health and social work sector and to physical work ability among those with lower grade occupations in the manufacturing and trade sectors.