Counties with dirtier air have more stroke deaths

American Stroke Association News Release – Poster WMP57, Session MP5

January 30, 2019 Categories: Scientific Conferences & Meetings, Stroke News

Study Highlights:

  • Counties with higher levels of fine particulate (PM2.5) air pollution have more stroke deaths and shorter life expectancies among their citizenry.
  • About half of U.S. counties have annual air pollution levels that exceed guidelines from the Environmental Protection Agency.

Embargoed until 4 a.m. CT/5 a.m. ET, Wednesday, Jan. 30, 2019

DALLAS, Jan. 30, 2019 — In a nationwide study, counties with dirtier air had higher rates of stroke deaths and shorter life expectancies, according to preliminary research to be presented in Honolulu at the American Stroke Association’s International Stroke Conference 2019, a world premier meeting for researchers and clinicians dedicated to the science and treatment of cerebrovascular disease.

Researchers examined the average yearly levels air pollution (PM2.5) that contains fine inhalable particles. Produced by diesel engines and the burning of coal, biomass and kerosene, this type of air pollution has previously been shown to enter the circulatory system and harm health.

Analyzing health data and pollution monitoring information from 1,561 counties across the United States between 2005 and 2010, researchers found the yearly average for fine air pollution ranged from 7.2 to 14.7 (average 11.75) micrograms per cubic meter.

“Overall, the annual average was at a level considered acceptable. However, 51 percent of counties had an annual average exceeding 12 micrograms per cubic meter, the annual average limit of the National Air Quality Standards for PM2.5 set by the Environmental Protection Agency (December 2012),” said Longjian Liu, M.D., Ph.D., lead author of the study and associate professor of epidemiology and biostatistics at the Dornsife School of Public Health at Drexel University in Philadelphia.

When researchers examined associations between county average PM2.5 pollution levels and health measures (age-adjusted rates in adults 35 years and older), they found:

  • The dirtier the air, the higher the rate of stroke deaths and shorter life expectancy in both men and women.

  • The higher the poverty rate and fewer health providers in a county, the greater the health impact of high pollution.

  • The highest impact on stroke was in the South. The new results raise the possibility that exposure to PM2.5 pollution may be a factor in creating the so-called “stroke belt” in the southern United States. Other possible contributors to excessive rates of stroke in these states are poverty, diet, smoking, the control of stroke risk factors and the availability of health services.

“To reduce the risk of stroke, clinicians should consider their patients’ likely exposure to air pollution along with other risk factors. They can ask patients whether they live or work in an urban industrial area or whether they are aware of sources of pollution near their home or workplace. Clinicians can then encourage at-risk patients to take measures to reduce their exposure when possible, such as avoiding major roadways during rush hour traffic, keeping car windows closed and setting the air conditioner to circulate internal air,” Liu said.

The researchers are currently analyzing other findings that emerged from the county comparisons, including associations between higher levels of PM2.5 pollution and a greater risk of other leading causes of death, including coronary heart disease, heart failure and cancer.

The study did not have separate information on the number of clot-caused and bleeding strokes.

Note: Scientific presentation is 6:10 p.m. HT/11:10 p.m. ET, Wednesday, Feb. 6, 2019.

Additional Resources:

Statements and conclusions of study authors that are presented at American Heart Association scientific meetings are solely those of the study authors and do not necessarily reflect association policy or position. The association makes no representation or warranty as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at https://www.heart.org/en/about-us/aha-financial-information.

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About the American Stroke Association

The American Stroke Association is devoted to saving people from stroke — the No. 2 cause of death in the world and a leading cause of serious disability. We team with millions of volunteers to fund innovative research, fight for stronger public health policies and provide lifesaving tools and information to prevent and treat stroke. The Dallas-based association officially launched in 1998 as a division of the American Heart Association. To learn more or to get involved, call 1-888-4STROKE or visit StrokeAssociation.org. Follow us on Facebook and Twitter.

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Karen Astle: 214-706-1392; karen.astle@heart.org

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