Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort
Background: Epidemiological studies have consistently demonstrated that exposure to fine particulate matter (PM2.5) is associated with increased risks of mortality. To a lesser extent, a series of studies suggest that living in greener areas is associated with reduced risks of mortality. Only a hand...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2019-07-01
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| Series: | Environment International |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0160412018328897 |
| _version_ | 1818877501505536000 |
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| author | Dan L. Crouse Lauren Pinault Adele Balram Michael Brauer Richard T. Burnett Randall V. Martin Aaron van Donkelaar Paul J. Villeneuve Scott Weichenthal |
| author_facet | Dan L. Crouse Lauren Pinault Adele Balram Michael Brauer Richard T. Burnett Randall V. Martin Aaron van Donkelaar Paul J. Villeneuve Scott Weichenthal |
| author_sort | Dan L. Crouse |
| collection | DOAJ |
| description | Background: Epidemiological studies have consistently demonstrated that exposure to fine particulate matter (PM2.5) is associated with increased risks of mortality. To a lesser extent, a series of studies suggest that living in greener areas is associated with reduced risks of mortality. Only a handful of studies have examined the interplay between PM2.5, greenness, and mortality. Methods: We investigated the role of residential greenness in modifying associations between long-term exposures to PM2.5 and non-accidental and cardiovascular mortality in a national cohort of non-immigrant Canadian adults (i.e., the 2001 Canadian Census Health and Environment Cohort). Specifically, we examined associations between satellite-derived estimates of PM2.5 exposure and mortality across quintiles of greenness measured within 500 m of individual's place of residence during 11 years of follow-up. We adjusted our survival models for many personal and contextual measures of socioeconomic position, and residential mobility data allowed us to characterize annual changes in exposures. Results: Our cohort included approximately 2.4 million individuals at baseline, 194,270 of whom died from non-accidental causes during follow-up. Adjustment for greenness attenuated the association between PM2.5 and mortality (e.g., hazard ratios (HRs) and 95% confidence intervals (CIs) per interquartile range increase in PM2.5 in models for non-accidental mortality decreased from 1.065 (95% CI: 1.056–1.075) to 1.041 (95% CI: 1.031–1.050)). The strength of observed associations between PM2.5 and mortality decreased as greenness increased. This pattern persisted in models restricted to urban residents, in models that considered the combined oxidant capacity of ozone and nitrogen dioxide, and within neighbourhoods characterised by high or low deprivation. We found no increased risk of mortality associated with PM2.5 among those living in the greenest areas. For example, the HR for cardiovascular mortality among individuals in the least green areas was 1.17 (95% CI: 1.12–1.23) compared to 1.01 (95% CI: 0.97–1.06) among those in the greenest areas. Conclusions: Studies that do not account for greenness may overstate the air pollution impacts on mortality. Residents in deprived neighbourhoods with high greenness benefitted by having more attenuated associations between PM2.5 and mortality than those living in deprived areas with less greenness. The findings from this study extend our understanding of how living in greener areas may lead to improved health outcomes. Keywords: Greenness, Mortality, PM2.5, Cohort study, Canada, Effect modification |
| first_indexed | 2024-12-19T13:59:17Z |
| format | Article |
| id | doaj.art-7a0e2fb21ef143fa80084194a246debb |
| institution | Directory Open Access Journal |
| issn | 0160-4120 |
| language | English |
| last_indexed | 2024-12-19T13:59:17Z |
| publishDate | 2019-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Environment International |
| spelling | doaj.art-7a0e2fb21ef143fa80084194a246debb2022-12-21T20:18:30ZengElsevierEnvironment International0160-41202019-07-01128292300Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohortDan L. Crouse0Lauren Pinault1Adele Balram2Michael Brauer3Richard T. Burnett4Randall V. Martin5Aaron van Donkelaar6Paul J. Villeneuve7Scott Weichenthal8Department of Sociology, University of New Brunswick, Fredericton, NB, Canada; New Brunswick Institute for Research, Data, and Training, Fredericton, NB, Canada; Corresponding author at: Department of Sociology, University of New Brunswick, 9 Macaulay Lane, Tilley Hall, Room 20, Fredericton, New Brunswick E3B 5A3, Canada.Health Analysis Division, Statistics Canada, Ottawa, ON, CanadaNew Brunswick Institute for Research, Data, and Training, Fredericton, NB, CanadaSchool of Population and Public Health, University of British Columbia, Vancouver, BC, CanadaPopulation Studies Division, Health Canada, Ottawa, ON, CanadaDepartment of Physics & Atmospheric Science, Dalhousie University, Halifax, NS, Canada; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USADepartment of Physics & Atmospheric Science, Dalhousie University, Halifax, NS, CanadaDepartment of Health Sciences, Carleton University, Ottawa, ON, CanadaDepartment of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, CanadaBackground: Epidemiological studies have consistently demonstrated that exposure to fine particulate matter (PM2.5) is associated with increased risks of mortality. To a lesser extent, a series of studies suggest that living in greener areas is associated with reduced risks of mortality. Only a handful of studies have examined the interplay between PM2.5, greenness, and mortality. Methods: We investigated the role of residential greenness in modifying associations between long-term exposures to PM2.5 and non-accidental and cardiovascular mortality in a national cohort of non-immigrant Canadian adults (i.e., the 2001 Canadian Census Health and Environment Cohort). Specifically, we examined associations between satellite-derived estimates of PM2.5 exposure and mortality across quintiles of greenness measured within 500 m of individual's place of residence during 11 years of follow-up. We adjusted our survival models for many personal and contextual measures of socioeconomic position, and residential mobility data allowed us to characterize annual changes in exposures. Results: Our cohort included approximately 2.4 million individuals at baseline, 194,270 of whom died from non-accidental causes during follow-up. Adjustment for greenness attenuated the association between PM2.5 and mortality (e.g., hazard ratios (HRs) and 95% confidence intervals (CIs) per interquartile range increase in PM2.5 in models for non-accidental mortality decreased from 1.065 (95% CI: 1.056–1.075) to 1.041 (95% CI: 1.031–1.050)). The strength of observed associations between PM2.5 and mortality decreased as greenness increased. This pattern persisted in models restricted to urban residents, in models that considered the combined oxidant capacity of ozone and nitrogen dioxide, and within neighbourhoods characterised by high or low deprivation. We found no increased risk of mortality associated with PM2.5 among those living in the greenest areas. For example, the HR for cardiovascular mortality among individuals in the least green areas was 1.17 (95% CI: 1.12–1.23) compared to 1.01 (95% CI: 0.97–1.06) among those in the greenest areas. Conclusions: Studies that do not account for greenness may overstate the air pollution impacts on mortality. Residents in deprived neighbourhoods with high greenness benefitted by having more attenuated associations between PM2.5 and mortality than those living in deprived areas with less greenness. The findings from this study extend our understanding of how living in greener areas may lead to improved health outcomes. Keywords: Greenness, Mortality, PM2.5, Cohort study, Canada, Effect modificationhttp://www.sciencedirect.com/science/article/pii/S0160412018328897 |
| spellingShingle | Dan L. Crouse Lauren Pinault Adele Balram Michael Brauer Richard T. Burnett Randall V. Martin Aaron van Donkelaar Paul J. Villeneuve Scott Weichenthal Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort Environment International |
| title | Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort |
| title_full | Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort |
| title_fullStr | Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort |
| title_full_unstemmed | Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort |
| title_short | Complex relationships between greenness, air pollution, and mortality in a population-based Canadian cohort |
| title_sort | complex relationships between greenness air pollution and mortality in a population based canadian cohort |
| url | http://www.sciencedirect.com/science/article/pii/S0160412018328897 |
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