The role of working conditions in educational differences in all-cause and ischemic heart disease mortality among Swedish men.

OBJECTIVES: This study aims to investigate the extent to which low job control and heavy physical workload in middle age explain educational differences in all-cause and ischemic heart disease (IHD) mortality while accounting for important confounding factors.

METHODS: The study is based on a register-linked cohort of men who were conscripted into the Swedish military at around the age of 18 in 1969/1970 and were alive and registered in Sweden in 2005 (N=46 565). Cox proportional hazards regression models were built to estimate educational differences in all-cause and IHD mortality and the extent to which this was explained by physical workload and job control around age 55 by calculating the reduction in hazard ratio (HR) after adjustments. Indicators of health, health behavior, and other factors measured during conscription were accounted for.

RESULTS: We found a clear educational gradient for all-cause and IHD mortality (HR 2.07 and 2.47, respectively, for the lowest compared to the highest education level). A substantial part was explained by the differential distribution of the confounding factors. However, work-related factors, especially high physical workload, also played important explanatory roles.

CONCLUSION: Even after accounting for earlier life factors, low job control and especially high physical workload seem to be important mechanistic factors in explaining educational inequalities in all-cause and IHD mortality. It is therefore important to find ways to reduce physical workload and increase job control in order to decrease inequalities in mortality.