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Effect Modification of Greenness on the Association Between Heat and Mortality: A Multi-City Multi-Country Study
16 Pages Posted: 25 Mar 2022
More...Abstract
Background: Identifying how greenspace impacts the temperature-mortality relationship in urban environments is crucial, especially given climate change and rapid urbanization. To date, studies on this topic have indicated conflicting findings and typically focus on a localized area or single country. We evaluated the effect modification of greenspace on heat-related mortality in a global setting.
Methods: We collected daily ambient temperature and mortality data for 452 locations in 24 countries and used Enhanced Vegetation Index (EVI) as the greenspace measurement. We used distributed lag non-linear model to estimate the heat-mortality relationship in each city and evaluated the effect modification of greenspace.
Findings: Cities with high greenspace value had the lowest heat-mortality relative risk of 1·19 (95% CI: 1·13, 1·25), while the heat-related relative risk was 1·46 (95% CI: 1·31, 1·62) for cities with low greenspace. A 1% increase of greenspace in all cities was predicted to reduce all-cause heat-related mortality by 0·48 (95% CI: 0·24, 0·63), decreasing approximately 50 excess deaths per year. 20% increase of greenspace would reduce 9·02% (95%CI: 8·88, 9·16) heat-related attributable fraction, and this would result in saving approximately 933 excess deaths per year in 24 countries.
Interpretation: Our findings can inform communities on the potential health benefits of greenspaces in the urban environment and mitigation measures regarding the impacts of climate change.
Funding Information: Funding was provided by the U.S. Environmental Protection Agency (RD83587101), the National Research Foundation of Korea (2021R1A6A3A03038675), National Institutes of Health (R01MD012769), Medical Research Council-UK (MR/R013349/1), Natural Environment Research Council UK (Grant ID: NE/R009384/1), and European Union’s Horizon 2020 Project Exhaustion (Grant ID: 820655).
Declaration of Interests: None.
Keywords: greenspace, temperature, mortality, effect modification
Suggested Citation: Suggested Citation