Depression link to stroke risk bolstered
MedWire News: A meta-analysis published in JAMA provides "strong evidence" that depression increases people's risk for having a stroke.
"Given the high prevalence and incidence of depression and stroke in the general population, the observed association between depression and stroke has clinical and public health importance," say Frank Hu (Harvard School of Public Health, Boston, Massachusetts, USA) and co-workers.
"More studies are needed to explore the underlying mechanisms and elucidate the causal pathways that link depression and stroke."
The team's meta-analysis included 28 prospective cohort studies, involving a total of 317,540 participants, 8478 of whom had a stroke during follow-up periods ranging from 2 to 29 years.
All but two of these studies reported hazard ratios for stroke that were adjusted for confounders, most commonly age, smoking status, body mass index, alcohol intake, physical activity, and comorbidities such as diabetes, hypertension, and coronary heart disease.
Overall, having depression was associated with a 45% increase in the participants' risk for having a stroke, of any type. This equates to an estimated absolute risk increase of 106 cases per 100,000 people per year, say the researchers.
The risk for fatal stroke was assessed in eight studies; in these, depression was associated with a 55% increase in risk, amounting to 22 additional cases per 100,000 people per year. There was also a 25% increase in risk for ischemic stroke, based on the results from six studies, representing an extra 53 cases per 100,000 people per year. Depression did not significantly affect the risk for hemorrhagic stroke, but this was assessed in just two studies.
"According to the most recent statistics, 9.0% (21 million) of US adults meet the criteria for current depression," say Hu et al. They estimate that 3.9% of stroke cases in the USA could be attributable to depression.
The researchers also found that antidepressant medication use was associated with a 41% increase in stroke risk. But they say that "the results should be interpreted cautiously because medication use can be a marker of depression severity, and many studies lacked information on dose and duration of medication use."
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By Eleanor McDermid