Study Points to a Connection between Depression and Stroke
The evidence linking depression to stroke is growing, with a recent study showing that older women who are depressed may be at particular risk. In a follow-up of more than 80,000 women in the Nurses' Health Study, researchers found that a history of depression in women ages 54 to 79 was associated with a 29 percent increase in stroke, when compared with women of the same age without a history of depressioneven when other risk factors were considered.
The Nurses' Health Study is one of the largest and longest-running investigations of factors that influence women's health. During the six years of followup, 1,033 strokes were documented, most of them ischemic strokes, which result from blockage in a blood vessel providing blood to the brain.
The reported prevalence of depression in study participants was 22 percent, consistent with what's expected for women of this age group. Compared with women who did not have a history of depression, the depressed women were younger, were more likely to be single, had a higher body mass index, smoked cigarettes and were less likely to be physically active. The depressed women also tended to have more coexisting conditions, such as diabetes, hypertension or heart disease. (Depression has been closely associated with other disorders that often coexist with stroke: diabetes, hypertension and cardiovascular disease.)
The study also found a significant increase in the risk of stroke in women who were taking antidepressant medications known as selective serotonin reuptake inhibitors. Researchers cautioned that the study results did not provide evidence that use of these medications may cause stroke; rather, medication use may simply indicate the severity of depression.
More study is needed to determine whether these medications actually do contribute to stroke risk, so stopping medication was not recommended.
Reasons for Depression/Stroke Link Are Speculative
Depression may contribute to stroke in a variety of ways, according to the study, published in 2011 in the journal Stroke. Late-life depression may indicate underlying vascular disease. Depression may be linked to inflammation, which can increase the risk of stroke and other conditions. Depression is also associated with poor health behaviorssmoking, physical inactivity, poor diet, lack of medication complianceobesity and other conditions, which might increase the risk of stroke.
The study authors noted that it's not clear exactly why depressed women are at higher risk. And few studies have been conducted specifically among middle-aged and elderly women, in whom the prevalence of depression is high and the risk of stroke is substantial.
The lifetime risk of stroke for women aged 55 to 75 years is about 20 percent, notably higher than the 17 percent or lower risk for men.
Recognizing that depressed women may be at higher risk of stroke may encourage physicians to focus not only on treating the depression but also on treating stroke risk factors and addressing unhealthy behaviors.