Maheswaran, R. orcid.org/0000-0002-3899-4421, Pearson, T., Beevers, S.D. et al. (2 more authors) (2014) Outdoor air pollution, subtypes and severity of ischemic stroke - a small-area level ecological study. INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS, 13. ARTN 23. ISSN 1476-072X
Abstract
Background: Evidence linking outdoor air pollution and incidence of ischemic stroke subtypes and severity is limited. We examined associations between outdoor PM 10 and NO 2 concentrations modeled at a fine spatial resolution and etiological and clinical ischemic stroke subtypes and severity of ischemic stroke. Methods: We used a small-area level ecological study design and a stroke register set up to capture all incident cases of first ever stroke (1995 – 2007) occurring in a defined geographical area in South London (948 census output areas; population of 267839). Modeled PM 10 and NO 2 concentrations were available at a very fine spatial scale (20 meter by 20 meter grid point resolution) and were aggregated to output area level using postcode population weighted averages. Ischemic stroke was classified using the Oxford clinical classification, the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiological classification, National Institutes of Health Stroke Scale (NIHSS) score and a pragmatic clinical severity classification based on Glasgow coma score, ability to swallow, urinary continence and death <2 days of stroke onset. Results: Mean (SD) concentrations were 25.1 (1.2) ug/m 3 (range 23.3-36.4) for PM 10 and 41.4 (3.0) ug/m 3 (range 35.4-68.0) for NO 2 . There were 2492 incident cases of ischemic stroke. We found no evidence of association between these pollutants and the incidence of ischemic stroke subtypes classified using the Oxford and TOAST classifications. We found no significant association with stroke severity using NIHSS severity categories. However, we found that outdoor concentrations of both PM 10 and NO 2 appeared to be associated with increased incidence of mild but not severe ischemic stroke, classified using the pragmatic clinical severity classification. For mild ischemic stroke, the rate ratio in the highest PM 10 category by tertile was 1.20 (1.05-1.38) relative to the lowest category. The rate ratio in the highest NO 2 category was 1.22 (1.06-1.40) relative to the lowest category. Conclusions: We found no evidence of association between outdoor PM 10 and NO 2 concentrations and ischemic stroke subtypes but there was a suggestion that living in areas with elevated outdoor PM 10 and NO 2 concentrations might be associated with increased incidence of mild, but not severe, ischemic stroke.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © Maheswaran et al.; licensee BioMed Central Ltd. 2014 This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
Keywords: | Stroke; Air pollution; Environmental exposure; Subtypes; Severity |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Health and Related Research (Sheffield) > ScHARR - Sheffield Centre for Health and Related Research |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 04 Aug 2016 08:04 |
Last Modified: | 04 Aug 2016 08:04 |
Published Version: | http://dx.doi.org/10.1186/1476-072X-13-23 |
Status: | Published |
Publisher: | BioMed Central |
Refereed: | Yes |
Identification Number: | 10.1186/1476-072X-13-23 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:103359 |