Aim: To quantify the associations of two aspects of the psychosocial work environment, job strain and long working hours, with the risk of incident stroke.

Methods: We conducted large-scale meta-analyses of working men and women from prospective cohort studies to evaluate job strain and long working hours at baseline as risk factors for incident stroke during a mean follow-up of 7–9 years. Job strain, which is one of several indicators of work stress, was defined according to the demand–control model, where those exposed to high psychological job demands in combination with low control (i.e. job strain) were compared with all others. Study-specific hazard ratios with 95% confidence intervals (CI) were estimated from 14 studies participating in the IPD-Work Consortium and were pooled in a random-effects meta-analysis (total N ¼ 196,380). The definition of long working hours varied from 45 hours or more to 55 hours or more per week, depending on study. Study-specific hazard ratios or odds ratios were pooled into a common estimate of relative risk from 17 studies, including cohorts from the IPD-Work Consortium and published studies identified via a systematic literature review (total N ¼ 528,908).

Results: During a mean follow-up time of 9.2 years, 2023 first-time stroke events were recorded in the job strain analysis. After adjusting for age and sex, no association was found between being exposed to job strain and the risk of overall stroke (hazard ratio 1.09, 95% CI 0.94–1.26) or haemorrhagic stroke (hazard ratio 1.01, 95% CI 0.75–1.36). However, an increased risk of ischaemic stroke was observed among those with job strain (hazard ratio 1.24, 95% CI 1.05–1.47). After further adjustment for socioeconomic status the hazard ratio was 1.18 (95% CI 1.00–1.39). In the analysis of long working hours, 1722 stroke cases were identified during a mean follow-up time of 7.2 years. After adjustment for age, sex and socioeconomic status, long working hours were associated with an increased risk of incident stroke (relative risk 1.33, 95% CI 1.11–1.61). Furthermore, a dose–response association between weekly working hours and risk of stroke was observed.

Conclusion: We observed an approximately 20% increase in the risk of ischaemic stroke for individuals exposed to job strain and a 30% increase in the risk of overall stroke among those working long hours. These results support the hypothesis that psychosocial factors in the work environment are important in the development of ill-health in terms of stroke. The potential mechanisms linking these workplace factors to increased stroke risk are unclear, but might involve both direct effects on the cardiovascular system through activation of the neuroendocrine stress response and dysregulation of the hypothalamopituitary axis, and indirect effects from changes in health-related behaviours, such as physical activity, diet and alcohol consumption.