Research Highlights:
- The number of trees, shrubs and grasses in an area – known as green space or greenness – can improve air quality, counteract air pollution and may reduce heart disease deaths.
- Policies that improve environmental factors also can improve cardiovascular health among a diverse population.
Embargoed until 4 a.m. CT/5 a.m. ET, Monday, Nov. 9, 2020
DALLAS, Nov. 9, 2020 — Green spaces – trees, shrubs and grasses – can improve air quality and may lower heart disease deaths, according to preliminary research to be presented at the American Heart Association’s Scientific Sessions 2020. The meeting will be held virtually, Friday, November 13 - Tuesday, November 17, 2020, and is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science for health care worldwide.
“We found that both increased greenness and increased air quality were associated with fewer deaths from heart disease,” said William Aitken, M.D., a cardiology fellow with the University of Miami Miller School of Medicine and UM/Jackson Memorial Hospital in Miami, Florida.
Greenness is a measure of vegetative presence (trees, shrubs, grass) often assessed by NASA imaging of the Earth and other methods. Here, researchers used the Normalized Difference Vegetative Index (NDVI), which measures wavelengths of visible and near-infrared sunlight reflected from the Earth’s surface via NASA satellite imagery. A higher index corresponds to more healthy vegetation, as chlorophyll typically absorbs visible light and reflects near-infrared light.
In this cross-sectional study conducted using national air quality, greenness, CVD and census data from 2014-2015, researchers measured greenness by county across the United States and compared it to national disease death rates from the Centers for Disease Control and Prevention’s Interactive Atlas of Heart Disease. They also overlaid data from the Environmental Protection Agency’s air quality measurements of particulate matter for each county and the Census Bureau’s information on age, race, education and income by county.
The analysis found:
- For every 0.10 unit increase in greenness, deaths from heart diseases decreased by 13 deaths per 100,000 adults. Greenness (NDVI) values ranged from 0.00 – 0.80.
- For every 1 microgram increase in particulate matter per cubic meter of air, death from heart disease increased by roughly 39 deaths per 100,000 adults.
“We found that areas with better air quality have higher greenness, and that having higher greenness measures, in turn, is related to having a lower rate of deaths from heart disease,” said Aitken, who collaborated on the research with University of Miami public health scientists.
“Given the potential cardiovascular benefits of higher greenness measures, it’s important that dialogue about improved health and quality of life include environmental policies that support increasing greenness. Policymakers should support greenness through efforts that promote environmental justice through equitable access to green spaces, clean air and clean water, as well as minimizing exposure to environmental hazards,” he added.
The researchers hope their results encourage clinical trials using built environment interventions (e.g., tree planting to increase vegetative presence and greenness) to improve cardiovascular health. “We will be performing a longitudinal study in Miami to assess if changes in neighborhood greenness over time are associated with changes in cardiovascular disease,” Aitken said.
The main limitations of this study include that it was cross-sectional and used a total of combined cardiovascular disease death rates.
Co-authors are Kefeng Wang, M.S.; Abraham Parrish, M.A., M.L.S.; Diego Celli, B.A.; Joanna Lombard, M.Arch.; Jose Szapocznik, Ph.D.; and Scott C. Brown, Ph.D. Author disclosures are in the abstract.
This study received no external funding.
Note: Session: Environmental Influences and Temporal Trends of Cardiovascular Diseases
Additional Resources:
- Multimedia, including a video perspective interview with American Heart Association volunteer expert, Joel Kaufman, M.D., MPH, may be downloaded from the right column of the release link https://newsroom.heart.org/news/more-green-spaces-can-help-boost-air-quality-reduce-heart-disease-deaths?preview=8d74bf846e8a5af21d56759eaaa28850
- AHA Statement: Particulate Matter Air Pollution and Cardiovascular Disease
- Air Pollution and Heart Disease, Stroke
- Breathing heavy wildfire smoke may increase risk of out-of-hospital cardiac arrest
- Counties with dirtier air have more stroke deaths
- For more news at AHA Scientific Sessions 2020, follow us on @HeartNews #AHA20.
Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee 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 biotech companies, device manufacturers and health insurance providers are available here, and the Association’s overall financial information is available here.
About the American Heart Association
The American Heart Association is a leading force for a world of longer, healthier lives. With nearly a century of lifesaving work, the Dallas-based association is dedicated to ensuring equitable health for all. We are a trustworthy source empowering people to improve their heart health, brain health and well-being. We collaborate with numerous organizations and millions of volunteers to fund innovative research, advocate for stronger public health policies, and share lifesaving resources and information. Connect with us on heart.org, Facebook, Twitter or by calling 1-800-AHA-USA1.
###
For Media Inquiries and AHA Expert Perspective:
AHA News Media in Dallas: 214-706-1173; ahacommunications@heart.org
Karen Astle: 214-706-1392; karen.astle@heart.org
For Public Inquiries: 1-800-AHA-USA1 (242-8721)
heart.org and stroke.org