Sporadic Weather May Raise Stroke Risk

Sporadic weather conditions may be tied to increased stroke hospitalizations and death rate, according to new research presented at yesterday's American Stroke Association's International Stroke Conference in San Diego.

The study was presented by Judith H. Lichtman, Ph.D., M.P.H., study author and an associate professor in Epidemiology at the Yale School of Public Health in New Haven, Connecticut.

Lichtman explained that she and her team came to their conclusions after analyzing nationwide data concerning well over 130,000 adults, 18 years and older, who were admitted to hospitals between 2009 and 2010 for ischemic stroke. They then compared this data to temperatures and dew point data of each initial hospitalization day per patient.

What the researchers found was a small but undeniable pattern indicating that increased temperature change and humidity in a single day increases the likelihood in stroke hospitalization. They also found that consistent warmer temperatures lead to a nearly one percent decrease in stroke risk and a 1.1 percent decrease in the odds of dying for those already hospitalized. This indicates that a region with a constantly warm and dry climate is likely the best place to be for people at-risk of having a stroke.

The type of stroke focused on in this study was the ischemic stroke, a common kind of stroke caused by a blood clot that blocks the flow of blood to or from the brain. No evidence has been found that says climate change affects any other type of stroke.

Lichtman explained in her presentation that the knowledge obtained through this study may help those at risk of having a stroke be more vigilant. Those who already have a high risk of stroke due to factors like high blood pressure, arterial disease, or high blood cholesterol, may want to stay indoors on days where humidity is high and the temperature fluctuates.

Lichtman notes that this study only provides evidence supporting the hypothesis that there is a link between climate change and stroke risk. She says that further research will be needed to understand the cause and effect relationship of this phenomenon.

Because the study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal. It should also be noted that the study did not establish a cause-and-effect relationship, but only presented evidence of numerical correlations.

An abstract of the presentation can be found published online through the American Heart Association.