There may be twice the risk of stroke among adults over age 50 who have persistent symptoms of depression than among those who do not, according to a study led by researchers at Harvard T.H. Chan School of Public Health and published online recently in the Journal of the American Heart Association, per a news release from the school.

Stroke risk, they found, may remain higher even after the symptoms of depression go away.

“If replicated, these findings suggest that clinicians should seek to identify and treat depressive symptoms as close to onset as possible, before harmful effects on stroke risk start to accumulate,” says lead author Paola Gilsanz, ?Yerby Postdoctoral Research Fellow at Harvard Chan School, in the release.

In the study, Gilsanz and the rest of the research team reviewed health information from 16,178 men and women aged 50 years and older participating in the Health and Retirement Study between 1998 and 2010, the release explains. Participants were also interviewed every 2 years about a variety of health issues, including symptoms of depression, history of stroke, and stroke risk factors. During this time period, 1,192 strokes occurred among the participants.

Researchers found, according to the release, compared to study participants who had a low number of depressive symptoms during the two consecutive interviews, those participants who had a high number of depressive symptoms during their two consecutive interviews were more than twice as likely to have a first stroke. Results also indicated that stroke risk remained elevated even among the participants whose symptoms of depression went away between interviews—particularly for women.

Participants with symptoms of depression that began between their first and second interviews did not show signs of elevated stroke risk, the release continues. Study participants younger than age 65 had a greater stroke risk linked to their symptoms of depression than older participants with symptoms of depression.

Researchers suggest that depression may influence stroke risk through physiological changes involving accumulation of vascular damage over the long term, the release states. Damage may also be incurred indirectly through depression’s effect on health behaviors, including increased risk of smoking, and physical inactivity, the release says.

The study’s approach calls for “replication of findings in independent samples, with people of different age groups, and exploring different reasons that depressive symptoms get better,” says senior author Maria Glymour, associate professor in the Department of Epidemiology and Biostatistics at the University of California, San Francisco, who worked on the research while attending the Harvard T.S. Chan School of Public Health, in the release.

“The surprising results make such replications even more urgent,” Glymour adds.

[Source: Harvard T.S. Chan School of Public Health]