A new study has tried to clarify our understanding of the relationship between depression and heart attack, by looking at the amount of calcification in coronary arteries and the aorta.

Depression and Atherosclerosis

Summarized by Robert W. Griffith, MD
September 26, 2005

Introduction

The link between severe depression and an increased risk of heart attack is well established, but little is known about why there should indeed be such a link. It's clearly not associated with other risk factors, such as smoking, high blood pressure, or diabetes. It's an open question as to whether depression is a result of coronary heart disease, or a cause or the condition. A study just published in the Archives of Internal Medicine goes some way towards answering this question.

What was done

University of Pittsburgh investigators wanted to test the theory that middle-aged women with a history of recurring severe depression would have signs of atherosclerosis. They used a technique called electron beam tomography (EBT) to look for calcification in the coronary arteries and the aorta.

In EBT, an ultra high-speed electron beam traverses the selected body area in a few seconds. Exposure to radiation is minimal and produces 3-dimensional images for evaluation. The exceptionally detailed graphics can be viewed from every possible angle. Ten times faster than more traditional CT scans, EBT is considered ideal for detection of calcification in coronary arteries.

The participants were 58 African American and 152 white women living in Pittsburgh, Pennsylvania. They had to be between 42 and 52, and have had at least one menstrual period in the previous 3 months. Furthermore, they had to be in good health, with no history of heart attack, heart failure, angina, diabetes, or use of female hormones. Exams were done to check their health - blood pressure, waist-hip measurements, body mass index (BMI), fasting blood glucose, blood lipids, and smoking status.

A so-called Structured Clinical Interview was used to allow trained MD or PhD interviewers to assess whether the participants had had none, or just one, depressive episode, or had experienced recurrent episodes.

EBT was used to assess the presence or absence of coronary artery and aortic calcification, and to determine a 'calcium score' for all 4 coronary arteries and the single aortic vessel.

What was found

One in four of the 210 women in the analyses (53, or 25%) met the criteria for a diagnosis of recurrent depression. There were no differences in race or the use of alcohol or cigarettes between those with and those without recurrent depression. However, the depressed women did have a higher waist-hip measurement ratio, and higher fasting glucose levels.

Coronary artery and/or aortic calcification were found in over half the participants. In women with recurrent depression, the proportion having calcification was higher than in women with none or only one depressive episode - 62% vs. 45%; this was a significant difference (i.e. it could not have occurred by chance alone).

A similar result was seen in the group of women with the highest calcification scores, compared with those with no or only a small amount of calcification - 36% vs. 19%; this was also a significant difference.

What these findings mean

This study shows that recurring depression in healthy women was linked to calcification in the coronary arteries and/or the aorta, which is considered evidence of atherosclerosis. Long-term exposure to depressive symptoms possibly increases the development of calcification, whereas a single episode of depression has less effect. The investigators say that this points to recurrent depression as a risk factor for atherosclerosis. Such an association might depend on several mechanisms:

• Depression may provoke poor eating habits, leading to weight gain (this was seen in the study as increased waist-hip measurement ratios and elevated fasting blood glucose levels).
• Depression has been shown to be linked to development of the metabolic syndrome (which includes increased waist size, higher fasting blood sugar, high blood pressure, etc).
• Major depression is associated with higher levels of inflammatory markers, such as C-reactive protein (CRP).

The findings fill a gap in our knowledge about the relationship between major depression and atherosclerosis, but they do not prove cause-and-effect. However, it does mean that people with repeated attacks of major depression should be particularly careful about their lifestyle - eating properly and exercising adequately - and seeing their doctor regularly for cardiovascular checkups.

Source

• Coronary and aortic calcification in women with a history of major depression. PK. Agatisa, KA. Matthews, JT. Bromberger,  et al., Arch Intern Med, 2005, vol. 165, pp. 1229--1236

Related Links
Depression: A Risk Factor for Heart Disease in Older People
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