WORK stress, resulting from great pressure at the work place, may increase the progression of atherosclerosis by 46% in people who have highly reactive personalities to stress. This is demonstrated by a study that was discussed at the XVI World Congress of Cardiology (May 18 to May 22) which was held in Buenos Aires and attended by 15,000 professionals from more than 100 countries.

The study, performed by researchers at the School of Public Health in Berkeley, US, found that the association of stress and very demanding work in a personality highly reactive to stress, results in the thickening of the internal walls of the carotid arteries and formation of atherosclerotic plaques which progressively obstruct blood flow.

Both factors are markers of the progression of atherosclerosis that underlies cardiovascular disease.

“Studies like these have shown that work stress is associated to cardiovascular disease,” states Dr C. Noel Bairey Merz, Director of the Preventive and Rehabilitative Cardiac Center at Cedars-Sinai in the US. “And, although it is difficult to estimate how many people are at risk of coronary disease because of work stress, the most recent analysis of the INTERHEART study directed by Dr Salim Yusuf makes it possible to estimate that from 20% to 30% of heart attacks can be attributed to psychological stress.”

The INTERHEART study, which covered 52 countries and a population of 25,000 patients, has shown a link between depression, work or family stress and acute myocardial infarction.

“In the INTERHEART study, psychosocial factors were shown to be more potent predictors of the incidence of myocardial infarction than diabetes, smoking, hypertension and obesity in the multivariate analysis,” says Dr Monica Acevedo B., cardiologist and assistant professor at the Cardiology Dept of the Pontifical Catholic University of Chile.

“The presence of these factors clearly increased the risk of infarction,” says Dr Néstor Vita of Argentina, Professor of Internal Medicine at the Rosario University Institute and Vice-President of the XVI World Congress of Cardiology, when referring to stress and depression. “A sub-trial made mostly in South America showed that the cardiovascular impact of these factors is greater in Latin America than in Western Europe.”

The prevention of modifiable cardiovascular risks factors, including stress, smoking, a sedentary lifestyle, obesity, hypertension, diabetes and hypercholesterolaemia, is the central theme of the XVI World Congress of Cardiology, the most important scientific event in world cardiology.

“The 21st century starts with the appearance of new epidemics, many related to each other, such as diabetes, the metabolic syndrome or stress,” Dr Vita states.

“The impact of stress on the cardiovascular apparatus is due to a direct connection between the brain and the heart. Although this link was intuited from the very beginning of medicine, technological progress has made it possible with experiments to take it to the field of medical truths,” he explained.

It is known today that psychological stress constitutes both a risk factor for cardiovascular disease and a triggering factor of cardiovascular events such as acute myocardial infarction.

“Psychological stress follows two different pathways,” Dr. Bairey Merz explains. “Indirectly, stress is linked to a poor compliance to healthy lifestyles and medical therapy; directly, stress causes blood vessel constriction, the formation of more blood clots, high blood pressure, a greater tendency to insulin and diabetes.”

Psychological stress activates the psycho-neuro-endocrine system that increases heart rate and blood pressure as well as releasing fatty acids and catecholamines.

“If this condition becomes chronic, it may lead to a quicker development and appearance of cardiovascular disease,” Dr Vita states. “In the consulting room, it is possible to assess the degree of stress and its repercussions on the cardiovascular system during the interview, or with even more sophisticated tests such as the gamma camera or positron emission tomography.”

In all cases, stress requires a multi-disciplinary approach: a clinician, a psychologist, a nutritionist and a kinesiologist; in more severe cases, anti-anxiety drugs can be used.

“Exercise and psychotherapy are fundamental for long term treatment. A change in lifestyle, difficult to achieve, must be the final goal of any treatment, which means a correct management of work load, time and money,” says Dr Vita. “The need for weekly and yearly rest is very important and one of the ways to achieve this is to strengthen inter-personal and family links.”

As to the possibility of implementing strategies to reduce the impact of work stress at the workplace itself, Dr Bairez Merz says: “Clinical studies have reported different results on the capacity of improving cardiovascular outcome. This field is in its infancy and more research is required.”

With reference to depression, another of the psychosocial factors which increasing evidence shows to be related to heart disease and which is estimated at 5% of the world population, Dr Acevedo comments: “Most studies suggest that the worst depression and, in general, depressive problems, are risk factors for developing cardiovascular disease in healthy subjects, in patients with an already established cardiovascular problem and in patients who have had a heart operation.”

Like chronic stress, depression makes a deep impact on the central nervous system and causes changes in the autonomic nervous system and the hypothalamus – the pituitary gland axis, which is associated with a greater propensity to abdominal fat and other metabolic disorders that increase the body’s resistance to insulin and the risk of developing type 2 diabetes.

“Platelet changes may also appear in depressed patients, causing coagulation and may increase the risk of coronary events,” Dr Acevedo explains. “Finally, the existence of more frequent endothelial dysfunction and consequent dilation of the arteries has been reported in depressive patients.”

All these factors explain why depression is associated with a higher cardiovascular risk.

It is significant that, according to international statistics, depression is more frequent in women than in men (the ratio is 1.7 to 1).

“This higher prevalence in women can be observed from early adolescence until the mid-50s,” Dr Acevedo comments. “As to depression in cardiac patients, after an infarction, it is much more prevalent in women than in men. The depressive syndrome is much more severe in women and tends to last longer than in men.”

“It is reported that after an infarction, there is a smaller social support net for women and both depression and a smaller support net are predictive factors of adverse cardiovascular events, cardiac death and more frequent recurrence of cardiac events.”

Dr Acevedo, member of the Panel of Experts on Women and Heart Disease of the World Heart Federation, adds: “Marital rather than work stress, which is more common in men, is a recurrent factor in cardiac events.”