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Are Greenspaces Good for Your Heart?

Published February 26, 2018

Sudden unexpected death (SUD), more commonly known as sudden cardiac death, is one of the leading causes of mortality in the United States, estimated to claim as many as 450,000 lives per year.  People at risk for SUD can include those with conditions such as heart disease, hypertension, and diabetes. That is why identifying preventive measures is a major priority for local public health officials, and of EPA researchers working in partnership to support their work.

One promising area currently under investigation is exploring the links between a healthy environment and a healthy heart. Agency and other research has already made a strong scientific case for how reducing exposure to particulate matter and other forms of air pollution can reduce the risk of cardiac events, especially for those already suffering from the impacts of cardiovascular disease.

A family takes a hike

Now, they are turning their attention to another promising area: the link between greenspaces, such as neighborhood forests, and healthier communities.  Agency researchers have recently published the results of two such studies.

In Exploring links between greenspace and sudden expected death: A spatial analysis (Wu, et al., 2018), they and their partners combined an examination of 396 SUDs recorded in Wake County, NC, between March 2013 and February 2015 with spatial analysis of multiple greenspace metrics (percent forest, grassland, average and near-road tree canopy, and diversity of tree canopy). “To our knowledge, this is the first study to examine the spatial patterns of SUD cases and explore potential associations between SUD incidence and greenspace,” the authors report. Results showed increased levels of SUD in areas with lower percentages of forest.

The study concludes: “…we found that SUD incidence was inversely associated with greenway density and percent forest after controlling for confounding factors such as household income, population density and race.”
 

The implication is clear: neighborhood forests may be good for our hearts. Illuminating the causes of why this might be the case is the subject of another recent EPA study:  Eco-Health linkages: assessing the role of ecosystem goods and services on human health using causal criteria analysis (de Jesus Crespo, et al. 2018). In that study, Agency researchers used a software tool called “Eco-Evidence” to comb through some 16 years of published, peer-reviewed scientific research to find evidence of causal links between greenspaces and human health benefits.

Using a framework previously used more widely for epidemiological studies, the researchers applied a numerical approach that combines individual studies in a way that allows for more broad conclusions. “The premise is that isolated studies may not offer a strong case for causality, but they may do so if considered collectively,” they state in their paper.  “This approach allowed us to fully characterize the cause-effect model and identify the greatest data gaps and strongest support.”

Using this novel approach for an eco-health study, they assessed 2,756 papers to hone in on those that offered causal relationships between greenspace and human health. They were then able to focus in on 212 papers for conducting a “causal criteria analysis,” examining evidence of the links between healthy ecosystems and four categories important to public health: gastrointestinal disease, respiratory illness, heat morbidity, and cardiovascular disease.

The researchers found consistent evidence of links between the beneficial effects of natural ecosystems, namely the ability of “ecosystems goods and services” to buffer potential and known health impacts in those four health areas, “and between greenspaces and certain health outcomes such as cardiovascular disease and heat morbidities.”

Both papers are adding to an emerging body of scientific research, much of it led by EPA scientists, showing direct links between the natural environments and human health. What they are learning is helping local communities better capture those benefits as it become increasingly clear that greenspaces can be good for the heart.

Sources and References Cited

Wu, J., Rappazzo, K. M., Simpson, R. J., Joodi, G., Pursell, I. W., Mounsey, J. P., ... & Jackson, L. E. (2018). Exploring links between greenspace and sudden unexpected death: a spatial analysis. Environment international, 113, 114-121. https://doi.org/10.1016/j.envint.2018.01.021

de Jesus Crespo, R., & Fulford, R. (2018). Eco-Health linkages: assessing the role of ecosystem goods and services on human health using causal criteria analysis. International journal of public health, 1-12. http://rdcu.be/HQar