To investigate whether the effects of shiftwork on long-term sickness absence vary according to the level of individual working time control (WTC).
A representative sample of Finnish employees (1447 men and 1624 women) was combined with a register-based follow-up. A negative binomial model was used in the analysis of long-term sickness absence days. The results were adjusted for various background and work-related factors.
Individual WTC decreased long-term sickness absence. The higher rate of sickness absences in shiftwork was mainly due to the lower level of WTC. Working time control decreased sickness absence equally in day work and shiftwork.
The negative health effects of shiftwork may be decreased by offering sufficient WTC. Establishments that use WTC as a human resource instrument may benefit from reduced absenteeism.