Review articleResidential green spaces and mortality: A systematic review
Introduction
About half of the world population is currently living in cities and it is projected that by 2030 three of every five persons will live in urban areas (Martine and Marshall, 2007). As the world continues to urbanize, sustainable development and liveability challenges in cities will increase (United Nations Department of Economic and Social Affairs, 2014). Certain environmental factors in urban settings, such as air pollution, noise and extremely high temperatures have been associated with increased mortality (Selander et al., 2009, Basagaña et al., 2011, Hoek et al., 2013). Some studies have suggested that natural outdoor environments might help reduce the levels of air pollution and noise, as well as extreme temperatures in cities, and therefore reduce the impact of these environmental factors on our health and life-expectancy (Shanahan et al., 2015, Wolf and Robbins, 2015). Moreover, studies have observed that people living near or having access to natural outdoor environments are more likely to be physically active and have better mental health and therefore to be healthier (Shanahan et al., 2015, Wolf and Robbins, 2015).
Previously a number of studies have associated natural outdoor environments with reduced mortality (Shanahan et al., 2015, Wolf and Robbins, 2015) but there is no systematic review synthesizing the evidence, nor a precise and global estimate of the reduction of the risk of mortality in adults in relation to these types of environments. These synthesis and estimates are of importance for healthcare professionals and policymakers while translating available evidence into salutogenic interventions and policies to improve public health in urban areas. We aimed to systematically review the evidence of an association between residential natural outdoor environments, particularly green and blue spaces (e.g. lakes, rivers, beaches, etc.), and mortality in adults. As a secondary aim we also conducted meta-analyses to explore the magnitude of and heterogeneity in the risk.
Section snippets
Search strategy and selection criteria
We followed the PRISMA statement guidelines for reporting systematic reviews and meta-analysis (Moher et al., 2010). The bibliographic search was carried out by two independent reviewers (MG and MTM) using MEDLINE (National Library of Medicine) and SCOPUS search engines using keywords related to natural outdoor environments (greenspace, green space, natural environment, urban design, built environment, blue space, park, forest) combined with keywords related to mortality (mortality, survival,
Results
A total of 706 articles were identified in MEDLINE and 99 in SCOPUS. Through other sources one article was also identified. After screening the title and the abstracts and checking for duplicates, 17 articles were chosen for full-text evaluation of which 12 were finally included in the systematic review (Fig. 1).
Most of the studies (seven) had ecological design (Hu et al., 2008, Richardson and Mitchell, 2010, Richardson et al., 2010, Richardson et al., 2012, Uejio et al., 2011, Harlan et al.,
Discussion
The present systematic review shows that there are only a limited number of studies evaluating the relationship between green space and mortality and that these studies are heterogeneous in design, study population, green space assessment and covariate data. We found evidence of a reduction of the risk of CVD mortality in areas with higher residential greenness. The results of the meta-analyses conducted support this conclusion. The current review also observes some evidence of the benefits of
Conclusion
Despite the limitations described so far, this review showed evidence of an association between residential greenness and CVD mortality. This is important if we take into account that CVDs are the leading cause of mortality and years of life lost in high-income countries and that its incidence is increasing in low- and middle-income countries (Global, 2014). Future studies should evaluate effects in these countries, for which no information is currently available. Additionally, future studies
Conflict of interest
The authors declare they have no actual or potential competing financial interests.
Acknowledgments
This project was funded by the CERCA Institutes Integration Program (SUMA 2013) [promoted and managed by the Secretariat for Universities and Research of the Ministry Economy and Knowledge of the Government of Catalonia (SUR), the Agency for Management of University and Research Grants (AGAUR) and the CERCA Institute]. Payam Dadvand is funded by a Ramón y Cajal fellowship (RYC-2012-10,995) awarded by the Spanish Ministry of Economy and Competitiveness. Margarita Triguero-Mas is funded by a
References (42)
- et al.
The relationship between trees and human health: evidence from the spread of the emerald ash borer
Am. J. Prev. Med.
(2013) - et al.
Noise and well-being in urban residential environments: the potential role of perceived availability to nearby green areas
Landsc. Urban Plan.
(2007) - et al.
Towards a better understanding of the relationship between greenspace and health: development of a theoretical framework
Landsc. Urban Plan.
(2013) - et al.
Does walking explain associations between access to greenspace and lower mortality?
Soc. Sci. Med.
(2014) - et al.
Active-transport walking behavior: destinations, durations, distances
J. Transp. Geogr.
(2013) - et al.
Effect of exposure to natural environment on health inequalities: an observational population study
Lancet
(2008) - et al.
Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement
Int. J. Surg.
(2010) - et al.
Gender differences in relationships between urban green space and health in the United Kingdom
Soc. Sci. Med.
(2010) - et al.
Intra-urban societal vulnerability to extreme heat: the role of heat exposure and the built environment, socioeconomics, and neighborhood stability
Health Place
(2011) - et al.
A cohort study relating urban green space with mortality in Ontario, Canada
Environ. Res.
(2012)