Does a stressful psychosocial work environment mediate the effects of shift work on cardiovascular risk factors?

Objectives Associations between shift work, chronic psychosocial work stres s, and 2 important cardiovascular risk factors, hypertension and atherogeni c lipids were studied.The hypothesis was tested that psychosocial work stre ss, as defined by the model of effort-reward imbalance, mediates the effect s of shift work on cardiovascular risk. Methods Altogether 2288 male participants aged 30-55 years in the baseline screening of the Swedish WOLF (work organization, lipids, and fibrinogen) s tudy underwent a clinical examination and answered a standardized questionn aire measuring shiftwork schedules, effort-reward imbalance at work, and he alth-adverse behavior. Results In addition to the direct effects of shift work on cardiovascular r isk, mediating effects of effort-reward imbalance at work were found. The r espective odds ratios (OR) ranged from 2.18 to 2.27 for hypertension and fr om 1.34 to 1.45 for atherogenic lipids. While the effects remained signific ant after extensive confounder control concerning hypertension, part of the observed effect on atherogenic lipids was due to behavioral influences. Conclusions Despite obvious limitations, the results indicated that a stres sful psychosocial work environment acts as a mediator of health-adverse eff ects of shift work on hypertension and, partly, atherogenic lipids. In term s of occupational health the findings call for a more comprehensive assessm ent of the health risks associated with shift work.