clear
Monday May 4th, 2015 3:06AM

Stroke risk tied to cold, humidity, weather swings

By The Associated Press
There may be a link between weather and the risk of suffering a stroke, say researchers who analyzed climate trends and hospital records on millions of Americans.

Cold weather, high humidity and big daily temperature swings seem to land more people in the hospital with strokes. As it got warmer, risk fell - 3 percent for every 5 degrees, the study found.

"Maybe some of these meteorological factors serve as a trigger," said Judith Lichtman, a Yale University stroke researcher who led the study. With global climate change and extreme weather like this week's freak storm in the South, "this could be increasingly important," she said.

Lichtman and colleagues from Harvard and Duke universities gave results of their study Wednesday at the American Heart Association's International Stroke Conference in San Diego. It is the largest and most detailed research on this issue.

Each year, about 800,000 Americans have a stroke. Most are due to clots that block a blood vessel to the brain, and high blood pressure is a major risk factor.

Some earlier studies found a seasonal trend to stroke rates, and there are biological reasons to think they are related, said one independent expert, Dr. Andrew Stemer, a neurologist at Georgetown University.

Blood vessels constrict in cold weather, which can raise blood pressure, he said. Extreme weather can trigger a stress reaction by the body, causing it to release substances "that not only increase the work of the heart" but make blood stickier and more likely to clot, Stemer said.

In cold weather "your body clamps down, there's cardiovascular stress," said Dr. Larry Goldstein, a Duke stroke specialist who worked on the study.

Conversely, "high humidity may cause dehydration," which also can raise the risk for clots and raise stress on the body, he said. "You know how you feel when you're out in hot, humid weather - you don't feel so hot."

Several of these same researchers published another study earlier this year that looked at stroke deaths from 1999 to 2006 among Medicare patients and found a pattern - higher rates in the winter, lower in summer and a small peak in July.

The new study looked at stroke hospitalizations, not just deaths, in a wider population of adults using a federal database covering all states except Idaho, North Dakota, Delaware and New Hampshire. Researchers also had daily climate data down to the county level from the National Climatic Data Center for 2010 and 2011.

Researchers tracked only strokes caused by clots, not the less common kind caused by a burst or bleeding blood vessel.

Lower temperatures, larger daily temperature changes and higher dew points (humidity) were tied to higher stroke hospitalization rates.

Each 5-degree increase in daily temperature fluctuation (the highest reading minus the lowest one) raised the chance of stroke hospitalization by 6 percent. Each 5-degree rise in the dew point (humidity) raised the risk by 2 percent.

The researchers did not establish a threshold when things were too hot - the point of the study was tracking the general trend, Lichtman said.

The results mean that during extreme weather, friends and relatives should "keep an eye on people that are at high risk, those who are older," she said.

During stressful weather conditions, "you want to watch your diet, watch your salt intake, regardless of what the temperatures are," and get enough fluids, said Daniel Lackland, a scientist at Medical University of South Carolina in Charleston.

Goldstein added this advice for people already at cardiovascular risk: "Stay in air conditioning in the summer and stay heated in the winter," so the weather outside affects you less.
© Copyright 2015 AccessNorthGa.com
All rights reserved. This material may not be published, broadcast, rewritten, or redistributed without permission.
Judge denies motions to move, delay Tsarnaev trial
Lawyers for Boston Marathon bombing suspect Dzhokhar Tsarnaev asked a federal appeals court Wednesday to overturn a judge's decision to not move his upcoming trial out of state.
10:02PM ( 4 months ago )
High court to adopt electronic filing of cases
The Supreme Court is belatedly developing an electronic filing system similar to those used in courts around the country, Chief Justice John Roberts said Wednesday in his annual end-of-year report.
7:57PM ( 4 months ago )
Storm brings snow, cold to West for New Year's
A blustery winter storm dumped snow and ice across the West on Wednesday, making driving treacherous in the mountains from California to the Rockies and forcing residents and party-goers in some usually sun-soaked cities to bundle up for a frosty New Year's.
5:19PM ( 4 months ago )
U.S. News
Grass fire impacts rush hour traffic on 985
Rush hour traffic on I-985 was slowed by a grass fire Wednesay afternoon with one lane closed while firefighters fought the blaze.
10:19PM ( 4 months ago )
Hall County conviction, sentencing to be reviewed by SCOGA
The State Supreme Court has agreed to hear the appeal of a Hall County man when they reconvene in January.
2:37PM ( 4 months ago )
Local/State News
Obama again avoids calling 1915 Armenian killings 'genocide'
WASHINGTON (AP) — President Barack Obama will once again stop short of calling the 1915 massacre of Armenians a genocide, prompting anger and disappointment from those who have been pushing him to ful...
1:00PM ( 1 week ago )
Ex-NFL star Hernandez convicted of murder, sentenced to life
FALL RIVER, Mass. (AP) — Former New England Patriots star Aaron Hernandez was convicted of first-degree murder and sentenced to life in prison Wednesday for a deadly late-night shooting, sealing the d...
8:54PM ( 2 weeks ago )
Clinton kicks off 2016 campaign online, heads next to Iowa
WASHINGTON (AP) — Hillary Rodham Clinton jumped back into presidential politics on Sunday, making a much-awaited announcement she will again seek the White House with a promise to serve as the "champi...
7:56PM ( 3 weeks ago )
Hall, White, Jefferson schools recognized nationally for use of technology
Three school districts in northeast Georgia - Hall, White, and Jefferson - have received national recognition for their use use of innovative technologies. They earned top spots in the Center for Digital Education's and the National School Boards Association's 10th annual Digital School Districts Survey.
By Staff
1:00PM ( 3 weeks ago )
US Capitol lockdown lifted after man fatally shoots himself
WASHINGTON (AP) — A precautionary lockdown of the U.S. Capitol was lifted after about two hours Saturday following a suicide by a man carrying a protest sign.The man died after shooting himself on the...
6:15PM ( 3 weeks ago )