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Member Research & Reports

Member Research & Reports

Brown: Increased Risk of Hemorrhagic Stroke for Women When Nitrogen Dioxide and Nitrogen Oxides Levels are Elevated

Is there any association between stroke and daily variations in ambient air pollution amongst women in the United States? This is the question that researchers from the Brown University School of Public Health sought to answer in their latest study published in the journal Environment International. The research team led by Dr. Shengzhi Sun, postdoctoral research associate and Dr. Gregory A. Wellenius, associate professor used data from the Women’s Health Initiative
The analysis was restricted to women who had no history of stroke prior to enrollment and experienced a stroke event between the time of enrollment and September 2012. Multiple air pollutants were analyzed. Stroke events were self-reported by the participants and then centrally adjudicated by trained neurologists using a standardized approach. 
The authors found that there was no association between daily variations in air pollution and the risk of stroke. However, they did find a positive association between the risk of hemorrhagic stroke and levels of NO2 and NOx in the three days prior to stroke. The observed associations were stronger amongst non-obese participants than obese participants. 
The evidence linking short-term exposure to air pollution with the risk of cerebrovascular events remains equivocal. The study finding of no association between air pollution and ischemic stroke was contrary to some existing studies that reported an association. The authors suggest that further research is still needed to elucidate the relationship between short-term exposure to ambient air pollution and the risk of stroke, especially in the populations who are younger or live in other countries. 

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