August 12, 2011

Depression Ups Stroke Risk In Women: Study

Women who suffer from depression may have an increased risk of stroke, according to a new study published in Stroke: Journal of the American Heart Association.

In a six-year study of more than 80,000 women followed during the Nurses' Health Study, researchers found that a history of depression was associated with a 29 percent increase in the risk of total stroke -- even after considering other risk factors. And women who used antidepressants -- especially selective serotonin reuptake inhibitors -- had a 39 percent increase in stroke risk.

The women in the study were all between the ages of 54 and 79 and none had a stroke before the study began. Researchers examined participants' symptoms of depression, use of antidepressants, and diagnoses of depression by doctors from 2000 to 2006. At the outset, 22 percent of women reported having depression, similar to the national prevalence of 20 percent of women. Over the course of the study, there were 1,033 stroke cases.

"Depression has now been linked to stroke as well as cardiovascular disease in general," internist Kathryn Rexrode, associate professor of medicine at Harvard Medical School, the study's senior author, told USA Today's Anita Manning. But, "these are modest elevations in risk," she added, and should not lead women to stop taking antidepressants.

"Although we found women who took antidepressants were at higher risk, I don't have anything to indicate it's because of the medications," she said.

While the findings were surprising, UK stroke experts said depression alone was unlikely to increase stroke risk, reports BBC News.

Compared to women without a history of depression, depressed women were more likely to be single, smokers and less physically active. They were also slightly younger, had a higher body mass index (BMI) and had high blood pressure, heart disease and/or diabetes.

Dr An Pan of the Harvard School of Public Health, who also worked on the research, said inflammation could be the physical mechanism linking depression and stroke.

However, "regardless of the mechanism, recognizing that depressed individuals may be at a higher risk of stroke may help the physician focus on not only treating the depression, but treating stroke risk factors such as hypertension, diabetes and elevated cholesterol as well as addressing lifestyle behaviors such as smoking and exercise," he said in a press release.

"Depression is a very serious condition which needs to be treated carefully by healthcare professionals," Dr Peter Coleman, deputy director of research at the UK's Stroke Association, told BBC News.

"This research appears to indicate that women suffering from depression may be less motivated to maintain good health or control other medical conditions such as diabetes and high blood pressure, which have an associated increased risk of stroke," said Coleman, who was not involved in the study.

"However, it is very hard to determine whether there is a direct link between depression and stroke risk and a lot more research is needed in this area before depression alone can be viewed as a stroke risk factor," he said. "It's important that anyone taking antidepressants should continue doing so, and anyone concerned about their overall stroke risk should speak to their GP."

Dr Pan said the findings may not apply to men. Depression is twice as likely to occur in women as in men; the reasons for the differences are not clear.

Philip Gorelick, director of the Center for Stroke Research at the University of Illinois College of Medicine at Chicago, who was not involved in the research, said the study is important because it finds a link between the risks of stroke and a history of depression.

"This relationship has been suspected for a long time, but has not received the study and attention that it might deserve," he told USA Today's Manning.

Among limitations of the study, the participants were mostly white registered nurses - it excluded women without detailed information on depression measures and the participants with onset of stroke at a young age.

"We cannot infer cause or fully exclude the possibility that the results could be explained by other unmeasured unknown factors," Pan said. "Although the underlying mechanisms remain unclear, recognizing that depressed women may be at a higher risk of stroke merits additional research into preventive strategies in this group."

Stroke is the third leading cause of death in the USA, following heart disease and cancer. Stroke affects 425,000 women each year, 55,000 more than men, according to figures from the National Stroke Association.

To reduce the risk of stroke, Pan said, women should make changes in their behavior. Quitting smoking, following a healthy diet and exercising are all good measures to take to decrease stroke risk, as well as depression.

Women should also work with doctors to control diabetes and blood pressure. If you might be depressed, talk to a doctor to see whether treatment would be beneficial, he added.

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