Friday September 21 2007
More research needs to be done on stressful events and heart damage
Survivors of traumas such as terrorist attacks or earthquakes are five times more likely to suffer a heart attack than the general population, The Times reported. The article said that according to the lead author of a study, ‘on the day of the 1994 Los Angeles earthquake heart deaths in the area were two to five times higher than normal’.
The study on which this story is based is a non-systematic review of previous research into stress and cardiovascular risks or events in the absence of physical illness.
The review discusses the effects of stress on the cardiovascular system. The effect of chronic psychological stress (such as depression and anxiety) on heart health is well researched, however, little is known about the effect of acute stressors (such as the death of a spouse, terrorist attacks, violence etc).
The statistic that the short news report has focussed on is based on studies briefly mentioned by the authors of this review. The Times neglected to mention the context that the review paper gave here, which is that many of the cardiovascular events actually occurred in people who already had coronary artery disease.
The authors of the review recommend that doctors take seriously patient symptoms that arise in conjunction with negative emotion and should help to alleviate unnecessary psychological strain. This seems sensible advice.
Where did the story come from?
Drs Daniel Brotman, Sherita Golden and Ilan Wittstein from Johns Hopkins Hospital in Baltimore, Maryland, USA carried out the study. One of the authors received financial support from the National Institute of Diabetes, Digestive and Kidney Diseases. The study was published in the peer-reviewed medical journal The Lancet.
What kind of scientific study was this?
The study was a non-systematic review of previous studies that looked for associations between stress events and cardiovascular effects.
The review included previous studies and articles that addressed the issues they were interested in that were mostly published within the past five years. Some important earlier studies were also included. This was not a systematic review as the authors did not include all the studies that were available.
The research was then drawn together into a structured discussion about the various aspects of stress and cardiovascular health. They also discussed articles that suggested physiological mechanisms that might be responsible for the associations.
What were the results of the study?
The authors suggest that psychological stress causes changes in the body that might negatively affect the cardiovascular system. In their discussion of this association, they provide an overview of what might be responsible and the possible implications for therapy.
What interpretations did the researchers draw from these results?
The authors suggest that there is a wealth of data suggesting a strong and consistent association of acute and chronic psychological stress with cardiovascular risk factors. Doctors, they say, should be aware of this and consider it when helping patients to alleviate ‘unnecessary psychosocial strain’ caused by changes in lifestyle and the treatment of mental illness.
What does the NHS Knowledge Service make of this study?
This is a non-systematic discussion of the evidence around the effects of ‘stress’ on cardiovascular health.
- The review discusses the plausible biological mechanisms that may be behind the association between stress and heart health. This adds further weight to the evidence. The relationship is complex though; people under stress may also be affected by other lifestyle factors that have an effect on their cardiovascular risk, for example they may overeat or start smoking. We need to consider all of these possible factors when trying to understand the relationship between stress and cardiovascular risk. Not all have been discussed in this review.
- The increased risk of cardiovascular disease with depression and anxiety is well established. However, less is known about the effects of acute stressors (such as death of a spouse, terrorist attacks, or violence) on heart health. The review looks at the results of some studies that have recorded death and coronary events such as heart attacks after exposure to acute stress. Unfortunately, the only way to get a reliable view of the effect acute stressors have on cardiovascular health is to carry out a systematic review of all the evidence available.
- The authors sensibly conclude that physicians should be aware of the link between psychological stress and cardiovascular health.
The commonly held belief that stress ‘causes’ heart attacks is supported by plausible biological mechanisms. However for the link to be proven as cause and effect, more evidence is needed from randomised controlled trials such as interventions aimed at reducing stress.
Sir Muir Gray adds...
Most people feel the effects of acute strain imposed by shock or tragedy. It is good to have the size of the effect quantified, but the existence of the effect can be of no surprise to anyone who has felt their heart leap and bump in their chest in the middle of some terrible experience.