A Review of the Health Benefits of Greenness

Abstract

Researchers are increasingly exploring how neighborhood greenness, or vegetation, may affect health behaviors and outcomes. Greenness may influence health by promoting physical activity and social contact; decreasing stress; and mitigating air pollution, noise, and heat exposure. Greenness is generally measured using satellite-based vegetation indices or land-use databases linked to participants’ addresses. In this review, we found fairly strong evidence for a positive association between greenness and physical activity, and a less consistent negative association between greenness and body weight. Research suggests greenness is protective against adverse mental health outcomes, cardiovascular disease, and mortality, though most studies were limited by cross-sectional or ecological design. There is consistent evidence that greenness exposure during pregnancy is positively associated with birth weight, though findings for other birth outcomes are less conclusive. Future research should follow subjects prospectively, differentiate between greenness quantity and quality, and identify mediators and effect modifiers of greenness-health associations.

Effects of Urban Green Space on Environmental Health, Equity and Resilience

“…Numerous studies in multiple countries have demonstrated that recreational walking, increased physical activity and reduced sedentary time were associated with access to, and use of green space in working age adults, children and senior citizens (Epstein et al 2006;Kaczynski and Henderson 2007;Kaczynski et al 2008;Sugiyama and Ward Thompson 2008;Cochrane et al 2009;Almanza et al 2012;Lachowycz et al 2012;Astell-Burt et al 2013;Schipperijn et al 2013;Lachowycz and Jones 2014;Sugiyama et al 2014;Gardsjord et al 2014;James et al 2015;Sallis et al 2016). Almanza et al (2012) used satellite images and GPS and accelerometer data from children in several communities in California, the United States to demonstrate that increased residential greenness was positively associated with moderate to vigorous physical activity.…”

Within What Distance Does “Greenness” Best Predict Physical Health? A Systematic Review of Articles with GIS Buffer Analyses

“…Many of the analyses in this review examined health outcomes for which multiple other reviews find consistent ties between greenness and physical health -namely physical activity, birth and developmental outcomes, and cardiovascular outcomes [1,7,[14][15][16]. The analyses in this review represent a relatively small sample of articles using a single analytic tool to estimate residential greenness.…”

“…Physical health outcomes were divided into 18 categories. These were adapted from categories identified in previous greenness and health literature reviews [1,7,8]. The manner of data collection for physical health outcomes was grouped into three categories, based on whether data were objective (i.e., biomarkers, vital signs), expert or clinician diagnoses (i.e., electronic medical records), or subjective (i.e., self-reported health questionnaires).…”

“…We narrowed our criteria to two items: did the analysis include a subjective measure of physical health as its dependent variable; and did the analysis account for the critical confounding variable -income? We chose the latter criteria because a robust body of work demonstrates that this variable, more than any other, partially explains the relationship between greenness and health outcomes [1]. Not including a measure of income -such as socio-economic status or the common proxy, level of education -overestimates positive relationships between greenness and health.…”

“…2 of 26 Geographic information systems (GIS) software packages (i.e., ArcMap) provide powerful tools to provide empirical evidence on how different distances in which greenness is measured impact physical health. A multitude of remote sensing and GIS datasets (i.e., Normalized Difference Vegetation Index (NDVI), land cover datasets, and park layers) can be uploaded into these packages to provide objective measures of green cover in countries around the world [1]. Buffer tools (the "Buffer(Analysis)" toolkit in ArcMap) can then calculate the percentage of greenspace -or relative "greenness" -within a specified geographic polygon, for example, the area surrounding a person's house.…”