Archive for April 12th, 2012
Depression and heart disease in women
Cardiovascular disease is the leading cause of death in women. Close to 43 million women in the United States have some form of cardiovascular disease — a term that includes both heart disease and stroke — and every year nearly 422,000 die of it. That’s more than succumb annually to all forms of cancer combined. Heart disease and stroke are also a major cause of life-altering disabilities.
Several behaviors and conditions — smoking, poor diet, physical inactivity, high cholesterol, obesity, high blood pressure, and diabetes — increase the risk of developing cardiovascular disease. Clinicians routinely screen their patients for these modifiable risk factors and recommend ways to address them.
Evidence has mounted that depression should be added to the list of risk factors for cardiovascular disease. Research suggests that depression increases the likelihood of developing heart disease and stroke, even after taking into account factors such as smoking.
The issue is important to consider for women in particular, because they are twice as likely as men to develop depression. Two investigations highlight the relationship between depression and cardiovascular disease in women.
Plenty of data suggest that depression and cardiovascular disease are linked, but it’s unclear whether screening for symptoms of depression can predict who will develop heart problems down the road. To investigate, researchers in Pennsylvania enrolled 1,454 women (average age 56) in a five-year study to determine whether depression would increase the likelihood of developing heart disease — and whether at-risk women could be identified ahead of time. Participants came from an ongoing investigation of heart disease and breast arterial calcifications.
At the start of the study, the women answered questions about their health and risk factors for heart disease, including personal and family medical history. They were also screened for depression with three yes-or-no questions:
- Do you often feel sad or depressed?
- Do you often feel helpless?
- Do you often feel downhearted and blue?
At the end of five years, 5.6% of the women without heart disease at the start of the study who answered “yes” to any of the depression screening questions developed heart disease, compared with 2% of women who answered “no” to all three questions. Moreover, the greater the number of “yes” answers, the greater the likelihood of developing the disease. Women who agreed that they often felt helpless showed the greatest increase in risk. The authors suggest that feeling helpless may indicate a deeper depression, resulting in a greater risk of heart disease.
Although research has linked depression to cardiovascular problems, relatively few prospective studies — which follow participants over time — have examined its role as a risk factor for stroke. Furthermore, few studies have focused on older women, who are at substantial risk for stroke. To help fill this gap, Harvard researchers analyzed data from the long-running Nurses’ Health Study, in which participants fill out questionnaires about their health every two years. For this study, the investigators followed 80,574 women, ages 54 to 79, for a six-year period to learn more about the association between depression and stroke.
Depressive symptoms were assessed in 1992, 1996, and 2000 with the five-item Mental Health Index, a validated indicator of major depression. Women were also considered depressed if they had been diagnosed with depression by a clinician or were using antidepressants. In 2000, about 22% of participants were depressed.
Between 2000 and 2006, 1,033 women had strokes that were confirmed through medical records, autopsy reports, and death certificates. The researchers found that women who were depressed had a 41% greater risk of stroke compared with women who never reported depression or antidepressant use.
Antidepressant use was also related to stroke risk. Whether they were considered depressed or not, women who took selective serotonin reuptake inhibitors (SSRIs), the most commonly prescribed antidepressants, were at 39% greater risk of stroke than nonusers. This finding is consistent with a 2009 study based on Women’s Health Initiative data that showed an increased stroke risk among postmenopausal women taking SSRIs. But reports on this matter have been inconsistent, and much more research is needed. It may be that antidepressants are a marker of depression severity rather than a cause of stroke. Also, antidepressants are used for pain and other disorders that in some yet-to-be-identified way may influence stroke risk. And SSRIs may affect the blood’s ability to clot, which may increase risk of hemorrhagic (“bleeding”) stroke.
Depression doesn’t affect only the brain. It causes a number of physical changes elsewhere in the body that can pave the way for cardiovascular disease. Depression increases low-grade inflammation, which plays a part in artery-clogging atherosclerosis and the rupture of cholesterol-filled plaque, which in turn can lead to a heart attack or stroke. Depression also boosts the production of stress hormones, which dull the response of the heart and arteries to demands for increased blood flow. It activates blood cell fragments known as platelets, making them more likely to clump and form clots in the bloodstream. Studies have also shown that depressed women have lower levels of high-density lipoprotein (HDL), the “good” cholesterol. (Low HDL levels are an independent risk factor for heart disease.)
Behavior changes brought on by depression may have an even more important impact. People who are depressed may find it hard to exercise, pay attention to what they are eating, control their weight, or take the medications they need to protect their health. They may also withdraw from friends, family, and social activities, which also increases the risk for cardiovascular problems.
Many questions remain, however. The exact mechanisms that link depression with cardiovascular disease may take a while to sort out. In the meantime, cardiovascular health is one more reason why people shouldn’t ignore the signs and symptoms of depression or put off doing something about them. As readers of this newsletter know, there are many ways to treat depression, including medications, various types of psychotherapy, and exercise (which also helps the heart and arteries).
Of course, the biggest obstacle to treating depression may be a person’s inability to recognize the problem or reluctance to seek treatment. Clinicians can promote better outcomes by routinely asking their patients about symptoms of depression and encouraging them to address these mood problems.
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