A collaborative study from investigators at McMaster University in Canada and Boston University presents evidence showing that people with high levels of four biomarkers in the blood may be more likely to develop a stroke than people with low levels of the markers. The new study was published recently in Neurology through an article entitled “Circulating biomarkers and incident ischemic stroke in the Framingham Offspring Study.”
"Identifying people who are at risk for stroke can help us determine who would benefit most from existing or new therapies to prevent stroke," explained lead study author Ashkan Shoamanesh, M.D., assistant professor at McMaster University and a member of the American Academy of Neurology. "Future research could also investigate whether lowering the levels of these biomarkers or blocking their action could be a way to prevent strokes. However, our study does not provide evidence that these markers are validated well enough to be implemented in clinical practice."
In this new study, researchers were able to measure, in the blood of people from the Framingham Heart Study Offspring Cohort who had never had a stroke, the levels of 15 biomarkers that have been previously associated with inflammation. The study consisted of 3,224 participants with an average age of 61 at the onset that were followed for an average of nine years. During that time, 98 people suffered a stroke.
Of the 15 biomarkers, four were associated with an increased risk of stroke—C-reactive protein (CRP), total homocysteine levels (tHcy), tumor necrosis factor receptor 2 (TNFR2), and vascular endothelial growth factor (VEGF). People with elevated tHcy were 32 percent more likely to have a stroke. Those with high VEGF were 25 percent more likely; those with high CRP were 28 percent more likely, and finally individuals with high TNFR2 were 33 percent more likely to have a stroke during the study.
With the addition of these four biomarkers to an existing method of predicting a person's stroke risk based on factors such as age, sex, cholesterol, and blood pressure—called the Framingham Stroke Risk Profile— the researchers hope to improve the ability to predict individuals who may develop a stroke.
While the researchers were excited by their findings, they are cautious about over-interpretation, noting that the study was observational—showing a relationship between high levels of the biomarkers and stroke. The new study does not, however, establish that the high levels cause a stroke. The authors also remarked that the biomarkers were measured only once and that they did not account for infections, chronic diseases, or other conditions that could have affected the results. Also, study participants are mainly of European ancestry, and the results may not apply to other populations.