When reciprocity fails: effort-reward imbalance in relation to coronary heart disease and health functioning within the Whitehall II study.

BACKGROUND: A deleterious psychosocial work environment, as defined by high efforts expended in relation to few rewards reaped, is hypothesised to increase the risk of future poor health outcomes. AIMS: To test this hypothesis within a cohort of London based civil servants. METHODS: Effort-reward imbalance (ERI) was measured among 6895 male and 3413 female civil servants aged 35-55 during the first phase of the Whitehall II study (1985-88). Participants were followed until the end of phase 5 (1997-2000), with a mean length of follow up of 11 years. Baseline ERI was used to predict incident validated coronary heart disease (CHD) events during follow up and poor mental and physical functioning at phase 5. RESULTS: A high ratio of efforts in relation to rewards was related to an increased incidence of all CHD (hazard ratio (HR) = 1.36, 95% CI 1.12 to 1.65) and fatal CHD/non-fatal myocardial infarction (HR = 1.28, 95% CI 0.89 to 1.84) during follow up, as well as poor physical (odds ratio (OR) = 1.47, 95% CI 1.24 to 1.74) and mental (OR = 2.24, 95% CI 1.89 to 2.65) functioning at phase 5, net of employment grade. A one item measure of high intrinsic effort also significantly increased the risk of these health outcomes, net of grade. ERI may be particularly deleterious with respect to CHD risk among those with low social support at work or in the lowest employment grades. DISCUSSION: Within the Whitehall II study, a ratio of high efforts to rewards predicted higher risk of CHD and poor physical and mental health functioning during follow up. Although the increased risk associated with ERI was relatively small, as ERI is common it could be of considerable public health importance.