Depression doubles risk of stroke in middle-aged women

Middle-aged women suffering from depression are more than twice as likely to have a stroke, a new study has warned.

In a 12-year Australian study of 10,547 women 47-52 years old, researchers found that depressed women had a 2.4 times increased risk of stroke compared to those who weren't depressed. Even after researchers eliminated several factors that increase stroke risks, depressed women were still 1.9 times more likely to have a stroke.

"When treating women, doctors need to recognize the serious nature of poor mental health and what effects it can have in the long term," said Caroline Jackson, Ph.D., study author and an epidemiologist in the School of Population Health at the University of Queensland in Australia. "Current guidelines for stroke prevention tend to overlook the potential role of depression."

This is the first large-scale study in which researchers examined the association between depression and stroke in younger middle-aged women. The closest comparison is with the U.S.-based Nurses' Health Study, which found a 30 percent higher risk of stroke among depressed women. However, the average participant's age in the Nurses' study was 14 years older.

Jackson and her colleagues analyzed survey results from the nationally representative Australian Longitudinal Study on Women's Health. Participants answered questions about their mental and physical health and other personal details every three years in 1998-2010.

About 24 percent of participants reported being depressed, based on their responses to a standardized depression scale and their recent use of anti-depressants. Self-reported responses and death records revealed 177 first-time strokes occurred during the study.

The researchers used statistical software and repeated measures at each survey point to analyze the relationship between being depressed and having a stroke.

To distinguish the independent effects of depression, they factored out various characteristics that can affect stroke risks, including: age; socioeconomic status; lifestyle habits such as smoking, alcohol and physical activity; and physiological conditions including high blood pressure, heart disease, being overweight and diabetes.

Although the increased stroke risk associated with depression was large in the study, the absolute risk of stroke is still fairly low for this age group, Jackson said. About 2.1 percent of American women in their 40s and 50s suffer from stroke. In the study, only about 1.5 percent of all women had a stroke. That number increased to slightly more than 2 percent among women suffering from depression.

Similar results could be expected among American and European women, Jackson said.

"We may need more targeted approaches to prevent and treat depression among younger women, because it could have a much stronger impact on stroke for them now rather than later in life," she said.

It's still unclear why depression may be strongly linked to stroke in this age group. The body's inflammatory and immunological processes and their effects on our blood vessels may be part of the reasons, she said.

The study has been published in the journal Stroke.