Workplace stress plays is an important risk factor for heart disease and diabetes

Stress at work is an important risk factor for the development of heart disease and diabetes, finds a study published online by the British Medical Journal.

Stress at work has been linked with heart disease, but the biological processes were unclear. This study provides new evidence for the biological plausibility of the link between work stress and heart disease.

Researchers examined the association between work stress and the metabolic syndrome (a cluster of factors that increases the risk of heart disease and type 2 diabetes) in 10,308 British civil servants aged between 35 and 55, over a 14 year period.

Work stress was measured on four occasions between 1985 and 1999. Components of the metabolic syndrome, such as obesity, high blood pressure, and high cholesterol levels, were measured between 1997 and 1999. Social position and health damaging behaviours, such as smoking, heavy alcohol consumption, and lack of exercise, were also recorded.

A dose-response relation was found between exposure to job stress and the metabolic syndrome, even after adjusting for other risk factors. For example, men with chronic work stress were nearly twice as likely to develop the syndrome than those with no exposure to work stress. Women with chronic work stress were also more likely to have the syndrome, but they formed a small group.

Both men and women from lower employment grades were more likely to have the syndrome, confirming previous reports that the syndrome has a social gradient.

The association between the metabolic syndrome and exposure to health damaging behaviours was stronger among men than women. Poor diet (no fruit and vegetable consumption), smoking, heavy alcohol consumption, and physical inactivity were all associated with higher odds of the syndrome.

Despite some study limitations, a dose-response relation exists between exposure to work stress and the metabolic syndrome, even after other risk factors are taken into account, say the authors.

One possible explanation is that prolonged exposure to work stress may affect the nervous system. Alternatively, chronic stress may reduce biological resilience and thus disturb the body's physiological balance (homoeostasis).

This study provides evidence for the biological plausibility of psychosocial stress mechanisms linking stressors from everyday life with heart disease, they conclude.