A prospective study of 10,308 men and women aged 35-55 in London's civil service departments found a dose-response relationship between chronic work stress and the metabolic syndrome. Employees with chronic work stress (three or more exposures) had an odds ratio of 2.25 (95% CI 1.31-3.85) for the syndrome compared to those without work stress, after adjusting for age and employment grade. The study provides evidence for the biological plausibility of the link between psychosocial stressors and heart disease. Work stress was measured using the iso-strain model, which considers high job demands and low job control. The metabolic syndrome was defined by the presence of three or more risk factors, including abdominal obesity, dyslipidaemia, high blood pressure, insulin resistance, and prothrombotic and proinflammatory states. The study found a social gradient in the metabolic syndrome, with those in lower employment grades more likely to have the syndrome. Adjusting for work stress reduced the social gradient by 11%, while adjusting for health behaviours reduced it by 16%. The study also found that health damaging behaviours such as smoking, poor diet, and physical inactivity were associated with higher odds of the syndrome. The results suggest that chronic work stress is an important risk factor for the metabolic syndrome, and that the social gradient in the syndrome may be partially explained by work stress and health behaviours. The study highlights the need for further research into the biological mechanisms linking chronic stress to the metabolic syndrome and heart disease.A prospective study of 10,308 men and women aged 35-55 in London's civil service departments found a dose-response relationship between chronic work stress and the metabolic syndrome. Employees with chronic work stress (three or more exposures) had an odds ratio of 2.25 (95% CI 1.31-3.85) for the syndrome compared to those without work stress, after adjusting for age and employment grade. The study provides evidence for the biological plausibility of the link between psychosocial stressors and heart disease. Work stress was measured using the iso-strain model, which considers high job demands and low job control. The metabolic syndrome was defined by the presence of three or more risk factors, including abdominal obesity, dyslipidaemia, high blood pressure, insulin resistance, and prothrombotic and proinflammatory states. The study found a social gradient in the metabolic syndrome, with those in lower employment grades more likely to have the syndrome. Adjusting for work stress reduced the social gradient by 11%, while adjusting for health behaviours reduced it by 16%. The study also found that health damaging behaviours such as smoking, poor diet, and physical inactivity were associated with higher odds of the syndrome. The results suggest that chronic work stress is an important risk factor for the metabolic syndrome, and that the social gradient in the syndrome may be partially explained by work stress and health behaviours. The study highlights the need for further research into the biological mechanisms linking chronic stress to the metabolic syndrome and heart disease.