A recent study published in The Lancet Planetary Health reports that adequate exposure to residential greenspace may reduce mortality risk associated with non-communicable diseases.
Study: Associations between residential greenspace exposure and mortality in 4 645 581 adults living in London, UK: a longitudinal study. Image Credit: metamorworks / Shutterstock.com
Background
Non-communicable diseases, including cardiovascular, metabolic, and respiratory diseases and cancers, are responsible for approximately 71% of deaths globally. In the European Union, about 25% of healthcare costs are utilized for the treatment of these diseases.
Evidence indicates that people living in greener neighborhoods are less likely to develop non-communicable diseases and die prematurely. Adequate exposure to greenspaces can reduce exposure to air and sound pollution, increase opportunities for physical activity, promote social interactions, and reduce stress which, collectively, are considered beneficial for preventing the development of non-communicable diseases.
In the current study, scientists explore the impact of residential greenspace quantity and access to all-cause mortality and non-communicable disease-related mortality.
Study design
Scientists derived the association between greenspace measures and mortality by linking 2011 United Kingdom Census data of London-dwelling adults 18 years and older to data from the U.K. death registry and the Greenspace Information for Greater London resource.
A greenspace was defined as any freely accessible park or garden. The greenspace quantity was determined by measuring the percentage area of residential neighborhoods covered by parks or gardens.
Greenspace access point density and distance to the nearest access point for each responder’s residential neighborhood were measured using a geographic information system. These measurements were taken for overall greenspaces as well as park-specific greenspaces.
For mortality risk assessment, deaths occurring between March 2011 and December 2019 from all causes, as well as those due to cardiovascular disease, cancer, respiratory disease, and type 2 diabetes, were included in the analysis.
The association between greenspaces and mortality was determined after adjusting for several confounding factors, including age, sex, ethnicity, social status, family status, household deprivation status, education, and household tenure.
Important observations
A total of 4,648,087 individuals who responded to the 2011 Census were included in the final analysis. The average age of the study cohort was about 48 years old, with 53.4% of the study cohort female. In terms of demographics, almost 67% of the participants were White, 12% South Asian, 9.7% Black, 1.3% Chinese, and 2.4% mixed.
During the mean follow-up period of 8.4 years, 8% of respondents had died. More specifically, 1.5% of the study cohort died due to cardiovascular disease, 2.1% because of cancer, 0.6% from respiratory disease, and less than 0.1% from type 2 diabetes.
Regarding greenspace quantity and accessibility, about 3.2% of residential neighborhoods are covered by parks or gardens. On average, the access point density was 6.3/km2, whereas the distance to the nearest access point was 763 meters.
Association between greenspace exposure and mortality risk
No significant associations were observed between overall greenspace coverage and risk of death from all causes and non-communicable diseases.
Considering park-specific greenspaces, one percentage point induction in regional and pocket park areas was associated with a reduction in all-cause mortality risk. In contrast, one percentage point induction in small open spaces was associated with an increased risk of both all-cause and cancer-related mortality. A pocket park was defined as areas for rest and recreation under 0.4 hectares.
An induction in all-cause and cancer-related mortality risk was observed with every ten additional greenspace access points per km2 in residential neighborhoods. However, no association of greenspace access point density was observed with cardiovascular disease-, respiratory disease-, and diabetes-related mortality risks.
Regarding park-specific greenspaces, a reduction in respiratory mortality risk was observed with every ten additional access points per km2 for pocket parks. In contrast, an induction in all-cause, cardiovascular, and cancer mortality risk was observed with every ten additional access points per km2 for small open spaces.
When both overall and park-specific greenspaces were considered, no significant associations were observed between distance to the nearest greenspace access point and all-cause mortality risk and non-communicable disease-related mortality risk.
Conclusions
Both positive and negative associations between greenspace quantity and access to mortality risks were observed in the current study. Notably, the study findings indicate that a reduction in mortality risk may be achieved by increasing the quantity and access of pocket parks in urban areas.
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