A stressful professional life heightens the chances of developing heart disease and diabetes, according to a long-term study of civil servants. Research into work stress and the “metabolic syndrome” ? which includes factors such as obesity, hypertension and high cholesterol ? has found evidence of a direct link between stress exposure and ill-health.

The 14-year study of more than 10,000 civil servants, aged between 35 and 55 when the research began, showed that men who experienced a lot of stress were twice as likely to suffer from the syndrome as those not exposed to stress. A smaller study of female workers suggested that high stress carried five times the risk.

Scientists from University College London carried out tests on the participants on four occasions between 1985 and 1999, including an analysis of components of the metabolic syndrome. Social position and patterns of behaviour that might affect health, such as smoking, heavy alcohol consumption and lack of exercise, were also recorded.

The research, published in the British Medical Journal, showed a “dose-response” relationship between job stress and the metabolic syndrome: the more stress a person experienced, the higher his chances of suffering syndrome symptoms leading to heart disease and type 2 diabetes. The trend held even after adjusting for other risk factors.

Both men and women from lower employment grades were more likely than those above them to have the syndrome, confirming the established trend that obesity, high blood pressure and other factors linked to heart disease and late-onset diabetes are linked to social status. Overall, fewer women were found to experience chronic stress at work. The association between the metabolic syndrome and exposure to health-damaging behaviour was stronger among men than women.

A diet without fruit and vegetables, smoking, heavy alcohol consumption and physical inactivity were all associated with higher odds of the syndrome.

Known as the Whitehall study, the research was based on tests on civil servants from 20 London departments. The authors, led by Tarani Chandola, of UCL's Department of Epidemiology and Public Health, said that, though the study had some limitations, a clear link had been found. “A dose-response association exists between exposure to work stress and the metabolic syndrome,” they conclude. Employees with chronic work stress have more than double the odds of the syndrome than those without work stress, after other risk factors are taken into account. “The study provides evidence for the biological plausibility of psychosocial stress mechanisms linking stressors from everyday life with heart disease.”

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