Long-term depression may double the risk of stroke in adults over 50 and stroke risk remains higher even after symptoms of depression go away, suggests a new study.
Lead author Paola Gilsanz of Harvard University said that the findings suggest that depression may increase stroke risk over the long term.
The study documented 1,192 strokes over 12 years. Compared to people without depression at either interview, people with high depressive symptoms at two consecutive interviews were more than twice as likely to have a first stroke and people who had depressive symptoms at the first interview but not the second had a 66 percent higher stroke risk.
Researchers did not evaluate whether depressive symptoms diminished because of treatment or for other reasons; but findings suggest that treatment, even if effective for depression, may not have immediate benefits for stroke risk.
The researchers also suggested that depression may have a stronger effect on women than men in terms of stroke risk. However, recent onset of depression was not associated with higher stroke risk.
Gilsanz said that looking at how changes in depressive symptoms over time may be associated with strokes allowed them to see if the risk of stroke increases after elevated depressive symptoms start or if risk goes away when depressive symptoms do.
Gilsanz added that they were surprised that changes in depressive symptoms seem to take more than two years to protect against an elevated stroke risk.
The study appears in the Journal of the American Heart Association