Weather Linked to Stroke Hospitalization and Death

Stroke hospitalizations have been linked to large temperature changes, higher humidity, and lower average annual temperatures, according to a study released by the Yale School of Public Health. “Weather is not something people would typically associate with stroke risk,” stated study author Judith H. Lichtman, Ph.D., M.P.H. in an American Heart Association (AHA) news release. “However, we’ve found weather conditions are among the multiple factors that are associated with stroke hospitalizations.”

The study examined a sample of 134,510 adults across the U.S. that suffered ischemic strokes from 2009 through 2010. Ischemic strokes are “caused by a blood clot that blocks blood flow in or leading to the brain,” noted the AHA. Researchers found that higher stroke hospitalization rates correlated with wider fluctuations in temperature and higher average dew points. In addition, lower average annual temperature was linked to higher rates of stroke hospitalizations and death. A 1°F increase in average temperature demonstrated a .86 percent decrease in stroke hospitalizations and a 1.1 percent decrease in the probability of dying in a hospital after an ischemic stroke. Increases in daily temperature fluctuation and average dew point were found to increase chances of hospitalization due to stroke, but did not increase the probability of dying in the hospital.

“This study suggests that meteorological factors such as daily fluctuations in temperature and increased humidity may be stressors that increase stroke hospitalizations,” stated Lichtman. “People at risk for stroke may want to avoid being exposed to significant temperature changes and high dew point and, as always, be prepared to act quickly if they or someone they know experiences stroke signs and symptoms.”

According to the American Stroke Association (ASA), stroke risk factors that people can change, treat, or control include:  high blood pressure, cigarette smoking, diabetes mellitus, carotid or other artery disease, peripheral artery disease, atrial fibrillation (a heart rhythm disorder), other heart disease or heart failure, sickle cell disease, high blood cholesterol, poor diet, and physical inactivity and obesity. Signs and symptoms of stroke include: face drooping; arm weakness; speech difficulty; sudden numbness or weakness in the leg, arm, or face; sudden confusion or trouble understanding; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, loss of balance or coordination; and sudden severe headache with no known cause, states the ASA.

The study was presented to the ASA’s Stroke Conference on February 12, 2014. The lead author concluded that “future research is needed to better understand the cause and effect of changes in weather conditions, as well as to explore potential mechanisms for this association.”