Introduction Ambient particulate matter ≤ 2.5 µm in aerodynamic diameter (PM2.5) exposure elevates the risk for cardiovascular disease morbidity (CVDM). The aim of this study is to characterise which area-level measures of socioeconomic position (SEP) modify the relationship between PM2.5 exposure and CVDM in Missouri at the census-tract (CT) level.
Methods We use individual level Missouri emergency department (ED) admissions data (n=3 284 956), modelled PM2.5 data, and yearly CT data from 2012 to 2016 to conduct a two-stage analysis. Stage one uses a case-crossover approach with conditional logistic regression to establish the baseline risk of ED visits associated with IQR changes in PM2.5. In the second stage, we use multivariate metaregression to examine how CT-level SEP modifies the relationship between ambient PM2.5 exposure and CVDM.
Results We find that overall, ambient PM2.5 exposure is associated with increased risk for CVDM. We test effect modification in statewide and urban CTs, and in the warm season only. Effect modification results suggest that among SEP measures, poverty is most consistently associated with increased risk for CVDM. For example, across Missouri, the highest poverty CTs are at an elevated risk for CVDM (OR=1.010 (95% CI 1.007 to 1.014)) compared with the lowest poverty CTs (OR=1.004 (95% CI 1.000 to 1.008)). Other SEP modifiers generally display an inconsistent or null effect.
Conclusion Overall, we find some evidence that area-level SEP modifies the relationship between ambient PM2.5 exposure and CVDM, and suggest that the relationship between air-pollution, area-level SEP and CVDM may be sensitive to spatial scale.
- AIR POLLUTION
- CARDIOVASCULAR DISEASES
- ENVIRONMENTAL HEALTH
- Health inequalities
- SOCIAL SCIENCES
Data availability statement
Data are available upon reasonable request.
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Contributors Design and analysis: ZHM, HHC, SES, NS. Collected data: HHC, SES, RD, NS. Performed analysis: ZHM. Wrote paper: ZHM, SES, HHC. Gaurantor: ZHM.
Funding This publication was made possible by grants to Emory University from the National Institute of Environmental Health Sciences of the National Institutes of Health under award numbers R01ES027892 and P30ES019776. Zachary McCann was also supported by the NIEHS T32 Training Program in Environmental Health and Toxicology (5T32ES12870). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
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Competing interests None declared.
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