A 12-year Australian study found that depressed middle-aged women face almost double the risk of having a stroke.

Caroline Jackson, study author and an epidemiologist in the School of Population Health at the University of Queensland in Australia 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 the period from 1998 to 2010. Self-reported responses and death records indicated 177 first-time strokes occurred during the study.

About 24 percent of participants in the study of 10,547 women reported being depressed, based on their responses to a standardized depression scale and their recent use of antidepressants. The study indicated that depressed women had a 2.4 times increased risk of stroke compared to those who weren't depressed.

"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 Jackson.

Even after researchers eliminated several factors that increase risk, depressed women were still 1.9 times more likely to have a stroke. Eliminated factors included 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. The researchers used statistical software and repeated measures at each survey point to analyze the relationship between being depressed and having a stroke.

This was the first large-scale study to examine the association between depression and stroke in younger middle-aged women. Participants' ages ranged between 47 and 52 years old. A US-based Nurses' Health Study found a 30 percent higher risk of stroke among depressed women; however, the average participant's age in that study was 14 years older than in the Australian study.

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 two percent among women suffering from depression.

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

Although it's still unclear why depression may be strongly linked to stroke in this age group, the cause may be found in the body's inflammatory and immunological processes and their effects on our blood vessels, she said. "We may need more targeted approaches to prevent and treat depression among younger women."

The study, published in Stroke: Journal of the American Heart Association, was co-authored by Gita Mishra, Ph.D.

Depression and Body Fat

The purpose of an unrelated study published by the American Psychosomatic Society in 2009 was to examine the relationship of depressive symptoms and visceral adipose tissue - body fat collecting around the organs. Citing prior research that showed an association between depression and central adiposity, the authors posited this same pathway may be contributing to cardiovascular disease (CVD) and diabetes risk.

"Compared with subcutaneous fat (SAT), visceral fat (VAT) is more metabolically active and a better indicator of CVD risk," the authors wrote. Subcutaneous fat is found just beneath the skin. The authors also noted results of the Dynamics of Health, Aging and Body Composition study found that VAT significantly predicted five-year risk of incident myocardial infarction in elderly women but not men.

In the study, "Depressive Symptoms and Increased Visceral Fat in Middle-Aged Women," researchers investigated the cross-sectional association between depressive symptoms, assessed by the Center for Epidemiological Studies Depression Scale (CES-D), and VAT and SAT, assessed by computed tomography, in a sample of 409 middle-aged women who participated in the Chicago site of the Study of Women's Health Across the Nation (SWAN). Participants included 44.7 percent African-Americans and 55.3 percent European Americans with a mean age of 50.4 years.

"We observed a strong association between depressive symptoms and VAT in middle-aged women, particularly among overweight and obese women," the authors wrote. Depressive symptoms, though, were unrelated to SAT.

Adjusted for age, race, and total percent fat, among other factors, their results showed that each one-point higher score on the CES-D was associated with 1.03-cm greater VAT. In fact, women with a CES-D score of 16, indicative of clinically relevant depressive symptomatology, had 24.5 percent more VAT than women with lower CES-D scores.

Further adjustment for Framingham Risk Score, a gender-specific algorithm used to estimate the 10-year cardiovascular risk of an individual, as well as physical activity did not alter the findings, and their findings did not vary by race.

The researchers discovered that the associations were strongest in obese and overweight women.

"Increased visceral fat may be one pathway by which depression contributes to excess risk for cardiovascular disease and diabetes," the authors concluded. The study, whose lead author was Susana Everson-Rose, was conducted at University of Minnesota, Yale University School of Medicine, and Rush University Medical Center.

Sources: Jackson C, Mishra G. Untitled. Stroke: Journal of the American Heart Association. 2013.

S.E. Rose, T.T. Lewis, K. Karavolos, S. Dugan, D. Wesley, and L. Powell. Depressive symptoms and increased visceral fat in middle-aged women. American Psychosomatic Society. 2009.