Long-Term Depression in Over-50s Could Double Stroke Risk, Study Finds
Long-term depression in people over 50 could more than double their risk of suffering a stroke, with the risk remaining significantly higher even after the depression allays, research suggests.
The US study of more than 16,000 people, which documented 1,192 strokes, found that onset of recent depression was not associated with higher stroke risk, suggesting the damage is done by depressive symptoms accumulating over time.
The study’s lead author, Paola Gilsanz, from Harvard University’s TH Chan School of Public Health, said: “Our findings suggest that depression may increase stroke risk over the long term. Looking at how changes in depressive symptoms over time may be associated with strokes allowed us to see if the risk of stroke increases after elevated depressive symptoms start or if risk goes away when depressive symptoms do. We were surprised that changes in depressive symptoms seem to take more than two years to protect against or elevate stroke risk.”
The research, published on Wednesday in the Journal of the American Heart Association, used data from between 1998 and 2010 from the Health and Retirement Study, which interviews a panel of representative Americans aged over 50 every two years, on their depressive symptoms, history of stroke, and stroke risk factors.
Gilsanz, with colleagues from universities in Washington, California and Minnesota, and Bronx Partners for Healthy Communities, found that people with high depressive symptoms at two consecutive interviews had a 114% higher risk of suffering a first stroke, compared with people without depression at either interview. Those who had depressive symptoms at one interview but not at the next had a 66% higher risk.
The researchers did not evaluate whether depressive symptoms diminished because of treatment but their findings suggest that even if treatment is effective, it may not have immediate benefits for stroke risk. They found that diminished depression may have a stronger effect on stroke risk in women than in men. The authors say that their work, together with previous research, point to a need for clinicians to treat depressive symptoms as early as possible.
Study senior author Maria Glymour, from the University of California San Francisco School of Medicine, said: “Although we now know that depression strongly predicts stroke on par with many other major stroke risk factors, we still need research to understand exactly why this link occurs and whether we can potentially reduce stroke risk by treating depression.”
Previous research has shown that depression is associated with an increased risk of high blood pressure, abnormalities of the autonomic nervous system and increased inflammatory responses. It might trigger underlying vascular problems, including infection or atrial fibrillation, and depressed people are also more likely to smoke and be less physically active.
Dr Shamim Quadir, research communications manager at UK charity the Stroke Association, said: “The links between depression and stroke are still unclear, but this latest study suggests that over the long term, depression could lead to damage within the body’s cardiovascular system.
“Anyone feeling depressed or concerned about their risk of stroke should speak to their GP.”
A separate study, which followed almost 140,000 adults in 17 countries, has found that testing hand-grip strength could be a cheap and easy way to predict stroke and heart attack risk.
The research, published in the Lancet on Thursday, found that every 5kg decline in grip strength, measured using a handgrip dynamometer, was associated with a 9% increase in the risk of having a stroke and 7% rise in the risk of having a heart attack.
Each 5kg decline was also associated with a 17% greater risk of cardiovascular death and mortality, an identical increased risk of non-cardiovascular mortality and a 16% greater risk of death from any cause.
Lead author Dr Darryl Leong, from the Population Health Research Institute, Hamilton Health Sciences and McMaster University, in Canada, said: “Grip strength could be an easy and inexpensive test to assess an individual’s risk of death and cardiovascular disease.
“Further research is needed to establish whether efforts to improve muscle strength are likely to reduce an individual’s risk of death and cardiovascular disease.”