Living in a greener neighbourhood could lower your risk of death

Not just parks but also streetside trees and lawns could have health benefits, study suggests.

In Japan, they call it shinrin-yoku – literally, “forest bathing.” Here, we might just call it a walk in the park. Either way, people around the world have an intuitive sense of the restorative power of natural environments. The question is: Why? Alex Hutchinson, The Globe and Mail

By Emily Chung, CBC News October 12, 2017

Trees stretching their canopies over city streets and grass tickling the sidewalk near your home are more than just pretty, they could actually be helping you live longer, a new study suggests.

Researchers at the University of New Brunswick used census and tax data to track 1.3 million non-immigrant Canadian adults living in the 30 biggest cities across the country, from Victoria to St. John’s, over 11 years starting in 2001. They measured the amount of greenery from trees, shrubs, grass and other plants within 250 metres (about two blocks) of the study subjects’ homes, using postal codes and satellite data. And they found that as the amount of greenery increased, people’s risk of death decreased “significantly” from natural causes.

“There was a lot bigger effect than I think any of us had been expecting,” said Dan Crouse, a health geographer and lead author of the study published this week in the journal The Lancet Planetary Health.

The greenery was measured on a scale of 0 to 1, using the NASA Aqua satellite, [where zero represented bare ground and 1 was complete coverage by dark green leafy plants]. The study found that each 0.15-point increase in greenness near subjects’ homes was associated with an eight to 12 per cent decrease in their risk of death.

Crouse said the link between greenness and lower death rates remained even after researchers accounted for the effects of air pollution.

While previous studies have shown that exposure to green space and parks can improve mental health and in some cases physical health, the researchers say this is the first big study to show a clear link between green surroundings and a lower risk of death.

It also suggests that green spaces don’t have to be actual parks in order to have health benefits.

“What we’re able to show with this study is really just having trees around where people are living is really important,” Crouse said.

The study found that the positive effect of green surroundings was greater for people in middle age than in other age groups.

The effect was also greater among those with higher incomes and more education, and among men compared to women. The researchers aren’t sure why.

The study also couldn’t tell what kind of greenery was being measured, although trees gave a higher score than grass. Nor could it explain why exposure to greenery had that kind of effect — researchers didn’t know how much access people had to the green spaces or whether they were getting more exercise in greener areas, for example.

View of nature

But Crouse said there are benefits to living near green spaces such as golf courses even for people who don’t use them.

“That space is still representing an absence of traffic congestion, an absence of the noise and pollution from cars. It’s going to have a real cooling effect in an urban area,” he said. “Just having a view of nature from your window … can be restorative. There’s a lot of ways that the greenness could be benefiting your health.”

Dr. Gillian Booth is a researcher at St. Michael’s Hospital who recently found that people who live in more walkable city neighbourhoods have lower rates of diabetes and obesity. She says the design of Crouse’s study looks sound, and she has used similar techniques in her own work.

She added that the results make her wonder what it is about green surroundings that are lowering death rates, and what threshold of greenness is needed to get those health benefits.

“Where do you draw the line and say there’s insufficient green space? And how much should you invest in it?” she said. “I think this is really exciting work in that it raises these types of questions.”

The study, she added, highlights that the way we design our communities can have a profound influence on residents’ health: “The potential reach is huge in terms of the number of people who could be benefiting from these health effects.”

Source CBC News

References

Urban greenness and mortality in Canada’s largest cities: a national cohort study, Dan L Crouse PhD, Lauren Pinault PhD, Adele Balram MPH, Perry Hystad PhD, Paul A Peters PhD, Hong Chen PhD, Aaron van Donkelaar PhD, Randall V Martin PhD, Richard Ménard PhD, Alain Robichaud MSc, Paul J Villeneuve PhD. The Lancet Planetary Health, Volume 1, Issue 7, e289-e297. DOI: http://dx.doi.org/10.1016/S2542-5196(17)30118-3

In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure, Simone Kühn, Sandra Düzel, Peter Eibich, Christian Krekel, Henry Wüstemann, Jens Kolbe, Johan Martensson, Jan Goebel, Jürgen Gallinat, Gert G. Wagner & Ulman Lindenberger. Scientific Reports 7, Article number: 11920 (2017) doi: 10.1038/s41598-017-12046-7

Further reading

Lifelong Residential Exposure to Green Space and Attention: A Population-based Prospective Study, Dadvand P, Tischer C, Estarlich M, Llop S, Dalmau-Bueno A, López-Vicente M, Valentín A, de Keijzer C, Fernández-Somoano A, Lertxundi N, Rodriguez-Dehli C, Gascon M, Guxens M, Zugna D, Basagaña X, Nieuwenhuijsen MJ, Ibarluzea J, Ballester F, Sunyer J. Environ Health Perspect. 2017 Sep 18;125(9):097016. doi: 10.1289/EHP694.

Noticing nature: Individual and social benefits of a two-week intervention, Passmore, Holli-Anne and Holder, Mark D. Journal of Positive Psychology 2017; Vol 12, Issue 6, 537-546. DOI: 10.1080/17439760.2016.1221126

Interacting with Nature Improves Cognition and Affect for Individuals with Depression, Marc G. Berman, Ethan Kross, Katherine M. Krpan, Mary K. Askren, Aleah Burson, Patricia J. Deldin, Stephen Kaplan, Lindsey Sherdell, Ian H. Gotlib, and John Jonides. J Affect Disord. 2012 Nov; 140(3): 300–305. Published online 2012 Mar 31. doi: 10.1016/j.jad.2012.03.012

City living and urban upbringing affect neural social stress processing in humans, Florian Lederbogen, Peter Kirsch, Leila Haddad, Fabian Streit, Heike Tost, Philipp Schuch, Stefan Wüst, Jens C. Pruessner, Marcella Rietschel, Michael Deuschle & Andreas Meyer-Lindenberg. Nature 474, 498–501 (23 June 2011) doi: 10.1038/nature10190 Published online 22 June 2011

Also see
National study suggests greener surroundings lead to a longer life University of New Brunswick
Living near a forest keeps your amygdala healthier Max Planck Institute for Human Development
This Is Your Brain on Nature National Geographic
Nature calms the brain and heals the body The David Suzuki Foundation
Living near green spaces linked to longer lives, study finds CBC News
Why is walking in the woods so good for you? The Globe and Mail
Rx: 50 mg Nature, Ad Lib Slate
How walking in the woods benefits your health mother nature network
Walkable neighborhoods linked with more active older adults Medical Xpress
Green space improves mental health, well-being CBC News
How the built environment impacts healthy ageing Medical Xpress
City living affects your brain, researchers find The Guardian
Living close to green spaces is associated with better attention in children EurekAlert! AAAS