Trajectories of working hours in later careers and their association with social and health-related factors: a follow-up study.

BACKGROUND: The aim was to identify working hours' trajectories in later work careers over a follow-up of 15-17 years and to examine their association with social factors and health. METHODS: A subsample from the Helsinki Health Study was extracted comprising employees of the City of Helsinki, Finland. Growth mixture modelling was used to identify different working hour trajectories. Age, gender, occupational class, marital status, health behaviour, physical and mental functioning and current pain were associated with trajectory membership. Relative risks (RRs) and their 95% confidence intervals (CIs) were estimated. RESULTS: A two-trajectory model was selected: 'Stable regular working hours' (90%) and 'Shorter and varying working hours' (10%). Women (RR 1.40, 95% CI 1.09-1.78), the oldest employees (RR 2.71, 95% CI 2.06-3.57), managers and professionals (RR 1.56, 95% CI 1.20-2.02), those reporting non-drinker (RR 1.66, 95% CI 1.32-2.10), those reporting sleeping more than 8 h per night (RR 1.74 95% CI 1.25-2.42) and those reporting poor mental functioning (RR 1.39 95% CI 1.15-1.68) had higher likelihood of belonging to the trajectory 'Shorter and varying working hours'. There were no differences between the trajectories in marital status, smoking, body mass index, current pain or physical functioning. However, routine non-manual workers (RR 0.74, 95% CI 0.55-0.98), and semi-professionals (RR 0.70, 95% CI 0.50-0.96) had lower likelihood of belonging to this trajectory. CONCLUSIONS: Trajectories of working hours in later work career differ by age, gender and occupational class but also by health behaviours and mental health functioning.