Depression has long been associated with an increased risk of cardiovascular disease. People who are depressed have higher rates of heart attack, stroke, angina, atrial fibrillation and heart failure. For women with depression, however, the risk for poor cardiovascular outcomes is even greater than it is for men. Evidence about these gender differences in cardiovascular outcomes is still controversial, in part because the reasons for these differences are not fully understood.

A new study has also found the association between depression and cardiovascular events is more significant in women than men, and the Japanese researchers suggested a few mechanisms to account for these differences.

Women in the study who were diagnosed with depression were about 25 percent more likely than men with depression to have a cardiovascular event.

The University of Tokyo researchers used data taken between 2005 and 2022 from the JMDC Claims Database, which offers a combination of both health data and insurance claims data from inpatient and outpatient settings in Japan.

Of the more than 4.1 million people enrolled in the study, almost 2.4 million were men. The average age of participants was 44. Depression was diagnosed in nearly 100,000 or 4.2 percent of the men and over 78,000 or 4.5 percent of the women.

All the study participants were followed for about 42 months to see if they developed cardiovascular issues such as heart attack, stroke, angina, atrial fibrillation and heart failure.

Obesity, hypertension, diabetes mellitus, dyslipidemia and physical inactivity were more common in both men and women with depression, but the women in the study who were diagnosed with depression were about 25 percent more likely to have a cardiovascular problem with depression.

What's behind women's seeming vulnerability? Women may have more severe and persistent symptoms of depression, the researchers said. They are also likely to experience depression during periods of significant hormonal changes, such as pregnancy and menopause. Women are also more prone to cardiovascular risk factors such as hypertension, diabetes and obesity when they are depressed.

In addition to these sex differences in rates of depression and cardiovascular disease or CVD, gender differences in healthcare use and treatment and biological factors including genetics and hormones may also put women with depression at greater risk for cardiovascular disease.

“Our study found that the impact of sex differences on the association between depression and cardiovascular outcomes was consistent,” said researcher Hidehiro Kaneko, an assistant professor at the University of Tokyo. “The identification of sex-specific factors in the adverse effects of depression on cardiovascular outcomes may help in the development of targeted prevention and treatment strategies that address the specific CVD risks faced by depressed patients.”

“Healthcare professionals must recognize the important role of depression in the development of CVD and emphasize the importance of a comprehensive, patient-centered approach to its prevention and management,” he said, adding that by treating and preventing a person's depression, providers could reduce the number of CVD cases.

The researchers note that the study had some limitations. It was observational and could not establish that depression was directly associated with cardiovascular events; the data did not take into account the severity and duration of depressive symptoms; and the physical and emotional effects of COVID-19 could be potentially confounding factors.

The study was published in Journal of the American College of Cardiology: Asia.