Is the impact of job control on stroke independent from socioeconomic status?: a large-scale study of the Swedish working population.

BACKGROUND AND PURPOSE The main purpose of this study was to test whether the impact of job control on stroke mortality is independent of socioeconomic factors. METHODS This was a register-based cohort study of nearly 3.5 million working people (25 to 64 years of age in the 1990 Swedish Census) with a 5-year follow-up for stroke mortality. Job control was aggregated to the data from a secondary data source (job exposure matrix). Gender-specific Poisson regressions were performed. RESULTS Compared with high job control occupations, low job control was significantly related to hemorrhagic (relative risk, 1.54; 95% CI, 1.10 to 2.17) and all-stroke mortality (relative risk, 1.50; 95% CI, 1.11 to 2.03) in women but not in men. The significance of job control in women was independent of all confounders included (marital status, education level, and occupational class). Class-specific analyses indicated a consistent effect of job control for most classes (significant for female lower nonmanuals). However, low job control did not increase the risk of stroke mortality in upper nonmanuals. CONCLUSIONS Job control was significantly related to hemorrhagic and all-stroke mortality in women but not in men.