The original Whitehall study, led by Sir Michael Marmot of University College London (UCL), studied 10,308 civil servants—male and female workers who were between the ages of 35 and 55 years in 1985-1988—working in London, England, starting in 1985.
Dr. Tarani Chandola, also with the UCL, who led this recent Whitehall II study, added to the work performed by Marmot and the initial Whitehall study. After the Whitehall study was completed, data was collection again in seven phases: 1989–90, 1991–93, 1995, 1997–99, 2001, and 2002–04.
The Chandola team looked at work stress, along with behavioral risk factors, metabolic syndrome, heart rate variability, cortisol levels, and incidences of CHD on the basis of death by CHD, non-fatal heart attacks, and angina.
They found out how stressed their subjects were at work by asking various questions with regards to their work schedules, job demands, amount of control over their jobs, and other similar topics. Over a twelve-year period, seven surveys were conducted to help researchers learn more about the amount of stress each subject was under while at work.
According to the researchers’ paper in the European Heart Journal (EHJ), they found that about “32% of the effect of work stress on CHD was attributable to its effect on health behaviors and the metabolic syndrome.” [EHJ: http://eurheartj.oxfordjournals.org/cgi/content/full/ehm584v1]
They also discovered that male and female subjects under the age of 50 years and determined to be under severe pressure (under heavy workloads and with little control over their jobs), according to the first two surveys, had a 68% higher risk of developing heart disease than other subjects.
These severely pressured workers had an increase in the chance for coronary heart disease based on direct causes (the stress itself) or indirect causes (more likelihood of an unhealthy lifestyle over other subjects, including unhealthy food, lack of exercise, excessive drinking, and smoking).
Chandola states, within a January 23, 2008 Reuters article, “This is the first large-scale population study looking at the effects of stress measured from everyday working life on heart disease. One of the problems is people have been skeptical whether work stress really affects a person biologically.” [Reuters: “Work-related stress can kill, study finds”]
The researchers conclude within their paper: “Work stress may be an important determinant of CHD among working-age populations, which is mediated through indirect effects on health behaviours and direct effects on neuroendocrine stress pathways.”
Thus, Chandola stated within a January 22, 2008 ScienceDaily.com article, "Stress at work is associated with an increased risk of coronary heart disease but the mechanisms underlying this association have remained unclear until now.” [ScienceDaily.com: “Stress At Work Is Linked To Heart Disease”]
These researchers found that there is an association between work stress and cardiovascular problems. Such an association brings about specific changes to the nervous system and the body's hormone levels that cause the increased risk. It increases the risk of heart attacks by weakening the human body’s natural abilities to cope with pressure.
Scientists already know that heart disease is the world's leading cause of death. Biologically, heart disease is caused by the accumulation of fatty deposits within the human body that over time harden and block arteries. Thus, they produce high blood pressure and other ailments that further damages blood vessels.
The results of this study is found in the European Heart Journal under the title “Work stress and coronary heart disease: what are the mechanisms?”.
The research team includes Tarani Chandola , Annie Britton, Eric Brunner, Harry Hemingway, Meena Kumari, Ellena Badrick, Mika Kivimaki, and Michael Marmot, all of the Department of Epidemiology and Public Health, University College London, and Marek Malik of the Department of Cardiac and Vascular Sciences, St George’s University of London.