Green spaces reduce the health gap between rich and poor — The Lancet

A bit of greenery near our homes can cut the “health gap” between rich and poor, say researchers from two Scottish universities.

The authors of the article in the British medical journal The Lancet (2008) called for planning authorities to consider making more green spaces available to improve the health and well-being of their residents.

A Review of the Health Benefits of Greenness

by Peter James, Rachel F. Banay, Jaime E. Hart & Francine Laden

Current Epidemiology Reports volume 2, pages 131–142 (2015)

Abstract: (underlining added)

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.

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UPDATE – 27 January 2019

More evidence about the connection between health and greenspace

+ about greenness and mental health:

From the National Academy of Sciences of the USA –

http://www.pnas.org/content/112/28/8567.abstract

“Nature experience reduces rumination and subgenual prefrontal cortex activation”

by Gregory Bratman [Stanford] et al.

Abstract (underlining added)

Urbanization has many benefits, but it also is associated with increased levels of mental illness, including depression. It has been suggested that decreased nature experience may help to explain the link between urbanization and mental illness. This suggestion is supported by a growing body of correlational and experimental evidence, which raises a further question: what mechanism(s) link decreased nature experience to the development of mental illness? One such mechanism might be the impact of nature exposure on rumination, a maladaptive pattern of self-referential thought that is associated with heightened risk for depression and other mental illnesses. We show in healthy participants that a brief nature experience, a 90-min walk in a natural setting, decreases both self-reported rumination and neural activity in the subgenual prefrontal cortex (sgPFC), whereas a 90-min walk in an urban setting has no such effects on self-reported rumination or neural activity. In other studies, the sgPFC has been associated with a self-focused behavioral withdrawal linked to rumination in both depressed and healthy individuals. This study reveals a pathway by which nature experience may improve mental well-being and suggests that accessible natural areas within urban contexts may be a critical resource for mental health in our rapidly urbanizing world.

+ about neighhbourhood trees and health (Toronto data):

From Scientific Reports on nature.com

http://www.nature.com/srep/2015/150709/srep11610/full/srep11610.html#t3

“Neighborhood greenspace and health in a large urban center”

by Omid Kardan [Chicago] et al.

Abstract (underlining added)

Studies have shown that natural environments can enhance health and here we build upon that work by examining the associations between comprehensive greenspace metrics and health. We focused on a large urban population center (Toronto, Canada) and related the two domains by combining high-resolution satellite imagery and individual tree data from Toronto with questionnaire-based self-reports of general health perception, cardio-metabolic conditions and mental illnesses from the Ontario Health Study. Results from multiple regressions and multivariate canonical correlation analyses suggest that people who live in neighborhoods with a higher density of trees on their streets report significantly higher health perception and significantly less cardio-metabolic conditions (controlling for socio-economic and demographic factors). We find that having 10 more trees in a city block, on average, improves health perception in ways comparable to an increase in annual personal income of $10,000 and moving to a neighborhood with $10,000 higher median income or being 7 years younger. We also find that having 11 more trees in a city block, on average, decreases cardio-metabolic conditions in ways comparable to an increase in annual personal income of $20,000 and moving to a neighborhood with $20,000 higher median income or being 1.4 years younger.

+ Human health and the loss of trees due to the Emerald Ash Borer

The relationship between trees and human health: evidence from the spread of the emerald ash borer

by Donovan GH¹, Butry DT, Michael YL, Prestemon JP, Liebhold AM, Gatziolis D, Mao MY

Am J Prev Med. 2013 Feb; 44(2):139-45. doi: 10.1016/j.amepre.2012.09.066.

Abstract (full text is not freely accessible)

BACKGROUND: Several recent studies have identified a relationship between the natural environment and improved health outcomes. However, for practical reasons, most have been observational, cross-sectional studies.

PURPOSE: A natural experiment, which provides stronger evidence of causality, was used to test whether a major change to the natural environment-the loss of 100 million trees to the emerald ash borer, an invasive forest pest-has influenced mortality related to cardiovascular and lower-respiratory diseases.

METHODS: Two fixed-effects regression models were used to estimate the relationship between emerald ash borer presence and county-level mortality from 1990 to 2007 in 15 U.S. states, while controlling for a wide range of demographic covariates. Data were collected from 1990 to 2007, and the analyses were conducted in 2011 and 2012.

RESULTS: There was an increase in mortality related to cardiovascular and lower-respiratory-tract illness in counties infested with the emerald ash borer. The magnitude of this effect was greater as infestation progressed and in counties with above-average median household income. Across the 15 states in the study area, the borer was associated with an additional 6113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular-related deaths.

CONCLUSIONS: Results suggest that loss of trees to the emerald ash borer increased mortality related to cardiovascular and lower-respiratory-tract illness. This finding adds to the growing evidence that the natural environment provides major public health benefits.