WEDNESDAY, Feb. 12, 2014 (HealthDay News) -- Imagine hearing a
weather forecaster warn that tomorrow could be "colder with a
chance of stroke."
As odd as that may seem, researchers have found possible
associations between certain weather conditions and the incidence
Larger daily temperature variations and higher humidity each
were associated with higher stroke hospitalization rates, according
to a new study.
The researchers also found that colder average annual
temperatures were associated with stroke hospitalizations and
death. An average daily temperature change of 5 degrees Fahrenheit
was associated with about a 6 percent increase in stroke risk and
hospitalization, the researchers said.
The reasons behind the findings are unclear, said study lead
author Judith Lichtman. And although the study showed an
association between weather and stroke risk, it didn't prove a
"Daily fluctuations in temperature and increased humidity may actually be stressors," said Lichtman, an associate professor of epidemiology at the Yale School of Public Health. "People at risk for stroke may want to avoid being exposed to significant temperature changes and high humidity."
How might fluctuating temperatures actually stress the body?
When temperatures go down, blood vessels in the skin constrict so
the body doesn't waste a lot of heat, said Dr. Mark Stecker,
chairman of the department of neurosciences at Winthrop-University
Hospital in Mineola, N.Y. When it's warm outside, the vessels open
up to increase heat loss through the skin.
Stecker, who was not part of the research team, said the idea
that weather can affect health is not new. "People think there
should be a relationship," he said. "They often say things like,
'My joints hurt -- maybe it's going to rain,' or, 'I got a cold
because it's cold outside.'"
There might be something to old wives' tales, he said, but it's
extremely difficult to know for sure.
The study, which is scheduled for presentation Wednesday at the
American Stroke Association meeting in San Diego, should be
considered preliminary until published in a peer-reviewed
For the research, Lichtman and her team used 2009-10 statistics
from a national database on hospital inpatients, noting ischemic
stroke hospitalizations of people 18 years old or older. Ischemic
strokes happen as a result of an obstruction within a blood vessel
supplying blood to the brain. The new study included data from
nearly 135,000 patients.
Temperature and dew point were pulled from the U.S. National
Climatic Data Center and linked to stroke discharges at the county
level. Factors such as region, season, age, gender, race and
patient health issues (such as diabetes and high blood pressure)
were considered in the analysis of the data.
This study isn't the first to suggest a relationship between
weather and stroke risk, Lichtman said. She said other studies done
in Europe and Japan have shown seasonal associations for weather
Lichtman suggested that people at risk of stroke who are living
in a region with extreme weather fluctuations might want to
minimize their exposure to the extremes. That might be as simple as
staying indoors with air conditioning on a hot day or ensuring
ample heating when it's especially cold outside, she said.
Fluctuating or extreme weather conditions should also raise
alertness for the signs and symptoms of stroke, Lichtman said.
For his part, Stecker said the research will have a minimal
impact on managing stroke risk.
"I'd tell a patient to not even think about it. People have enough anxiety already," he said. It's more important to focus on other risks, such as diet, weight, blood pressure, exercise and whether they take a statin to treat high cholesterol, he said.
Lichtman said she wants to do more research to better understand
whether there is a more defined cause-and-effect relationship
between weather and stroke risk, and explore the cause in more
depth. "Understanding the reasons for the associations between
weather conditions and stroke could lead to the development of
targeted preventive interventions," she said.
Lichtman, who is married to a musician, said she knows firsthand
how weather can affect us. "My husband's violin responds to extreme
weather temperatures and humidity all the time," she said.
Learn more about the signs and symptoms of stroke from the
U.S. Centers for Disease Control and
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