Healthcare News & Insights

Study links depression to higher risk of stroke

ThinkstockPhotos-178411299A new study published in the Journal of the American Heart Association found that people with depression, or even symptoms of depression, have a higher risk for stroke. If you’re thinking you already knew that, here’s something you probably didn’t know: Even if depression symptoms go away, the risk for stroke doesn’t. 

Finding out the reason for the link could help hospitals lower their readmission rates by preventing strokes.

Previous research has found that depression is associated with an increased risk of high blood pressure, abnormalities of the autonomic nervous system and increased inflammatory responses, which might trigger underlying vascular problems.

This study, led by researchers at Harvard T.H. Chan School of Public Health, is significant because it’s the first to look at how changes in depressive symptoms predict changes in stroke risk.

The study looked at data from more than 16,000 people age 50 and older from the Health and Retirement study. Every two years, the study participants were asked questions about their depression, stroke history and behavior that might put them at risk for stroke.

The survey was based on yes/no questions about whether the person, in the previous week:

  • had feelings of being depressed
  • felt as if everything was an effort
  • had sleep issues
  • had an inability “to get going,” and
  • had feelings of loneliness.

Over the course of the 12 years of the analysis, 1,192 first-time events were documented.

Results

Study participants with recent onset of depression were found not to have a higher risk for stroke, suggesting that damage from depressive symptoms accumulates over time.

However, study participants who reported depressive symptoms at two consecutive interviews had a 114% high risk of their first stroke, compared to people without depression at either interview.

And for those participants who reported having depressive symptoms at one interview, but not the following interview, had a 66% higher risk of stroke. Even the researchers were surprised by this. They expected the stroke risk to be back at baseline.

One hypothesis is that depression often goes hand-in-hand with unhealthy behaviors, such as smoking and being less physically active, which can increase cardiovascular disease.

The study also found that diminished depression may have a stronger effect on stroke risk in women, and that participants younger than 65 had greater stroke risk linked to their depressive symptoms than older participants with depressive symptoms.

One thing the study didn’t look at was whether the depressive symptoms diminished because of treatment or for other reasons. Findings, however, suggest that treatment, even if effective for depression, may not have immediate benefits for stroke risk.

“If the causal mechanisms linking depression and stroke are exclusively long term, reductions in stroke risk would require years of successful symptom management,” wrote the researchers.

AHA spokesperson Dr. Philip Gorelick, medical director of Mercy Health in Grand Rapids, MI, told CNN he isn’t surprised by the findings. “I think the depression may have been going on for longer than we realize, so the risk factors have been taking hold over a period of time,” he said. “So I’m not surprised that even after symptoms of depression are remitting, there is still a risk.”

Possible test

Additional research is needed to understand why this link occurs and whether providers can reduce stroke risk by treating depression.

Until that happens, you may want to have your providers identify people who are depressed  or have depressive symptoms and help them get treatment after they’re discharged. This will hopefully reduce their risk of stroke, and possible future hospitalizations.

An additional test your providers can do to predict stroke, which is inexpensive and simple, is hand-grip strength.

A recent study published in The Lancet found that grip strength was inversely associated with all-cause mortality, cardiovascular mortality, non-cardiovascular mortality, myocardial infarction and stroke.

Using a handgrip dynamometer, the study found for every 5 kg reduction in grip strength there was:

  • a 9% increase in stroke risk
  • a 7% increase in heart attack risk
  • a 17% higher risk of cardiovascular death
  • a 17% increased risk of noncardiovascular death, and
  • a 16% greater risk of all-cause death.

It’s thought that the lack of muscle strength may point to an increased risk of a variety of detrimental outcomes in adults around the world.

Once again, further research is needed to identify determinants of muscular strength and to test whether improvement in strength reduces these detrimental outcomes.

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