Stroke risk tied to cold, humidity, weather swings - KSWO 7News | Breaking News, Weather and Sports

Stroke risk tied to cold, humidity, weather swings

By MARILYNN MARCHIONE
AP Chief Medical Writer

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.

___

Online:

Stroke information: www.strokeassociation.org

___

Marilynn Marchione can be followed at http://twitter.com/MMarchioneAP

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Local NewsNewsMore>>

  • Kavanaugh's accuser wants FBI probe before she testifies

    Kavanaugh's accuser wants FBI probe before she testifies

    Tuesday, September 18 2018 1:30 AM EDT2018-09-18 05:30:22 GMT
    Tuesday, September 18 2018 11:22 PM EDT2018-09-19 03:22:40 GMT
    (AP Photo/Alex Brandon). In this Sept. 6, 2018 photo, Supreme Court nominee Brett Kavanaugh reacts as he testifies after questioning before the Senate Judiciary Committee on Capitol Hill in Washington. Official Washington is scrambling Monday to assess...(AP Photo/Alex Brandon). In this Sept. 6, 2018 photo, Supreme Court nominee Brett Kavanaugh reacts as he testifies after questioning before the Senate Judiciary Committee on Capitol Hill in Washington. Official Washington is scrambling Monday to assess...

    Republicans reversed course and agreed to the hearing in the face of growing demands by GOP senators to hear directly from Kavanaugh and Christine Blasey Ford, now a psychology professor in California.

    Republicans reversed course and agreed to the hearing in the face of growing demands by GOP senators to hear directly from Kavanaugh and Christine Blasey Ford, now a psychology professor in California.

  • Duncan woman reappointed to Oklahoma Health Care Authority Board of Directors

    Duncan woman reappointed to Oklahoma Health Care Authority Board of Directors

    Tuesday, September 18 2018 11:22 PM EDT2018-09-19 03:22:35 GMT

    A Duncan woman has been reappointed to serve on the Oklahoma Health Care Authority Board of Directors. Tanya Case was appointed to serve a second four-year term on the board by House Speaker Charles McCall. She will help oversee the agency responsible for the care and health of over one-million Oklahomans. Case has worked in health care for 35 years, with much of that spent in leadership positions. 

    A Duncan woman has been reappointed to serve on the Oklahoma Health Care Authority Board of Directors. Tanya Case was appointed to serve a second four-year term on the board by House Speaker Charles McCall. She will help oversee the agency responsible for the care and health of over one-million Oklahomans. Case has worked in health care for 35 years, with much of that spent in leadership positions. 

  • Flood threat from Florence remains in Carolinas; storm moves north

    Flood threat from Florence remains in Carolinas; storm moves north

    Tuesday, September 18 2018 11:21 PM EDT2018-09-19 03:21:03 GMT

    Rivers in North and South Carolina have reached or will reach flood levels in coming days, likely leading to more deaths caused by Florence.

    Rivers in North and South Carolina have reached or will reach flood levels in coming days, likely leading to more deaths caused by Florence.

Powered by Frankly