Spatial analysis of exposure to traffic-related air pollution at birth and childhood atopic asthma in Toronto, Ontario
- DOI
- Language of the publication
- English
- Date
- 2015-06-26
- Type
- Article
- Author(s)
- Shankardass, K.
- Jerrett, M.
- Dell, S.D.
- Foty, R.
- Stieb, D.
- Publisher
- Elsevier
Abstract
Findings from the Toronto Child Health Evaluation Questionnaire (TCHEQ) study indicate that early childhood exposure to traffic-related air pollution (TRAP) is related to the onset of atopic childhood asthma. To test this hypothesis further, we investigated whether spatial patterns in the birth neighbourhood of TCHEQ subjects with atopic asthma (136 of 909 schoolchildren in grades 1–2) could be explained by TRAP and other risk factors. If a causal relationship exists between early childhood residential exposure to TRAP and the development of atopic asthma, we hypothesise that (1) clusters of current asthma should exist around the place of residence at birth, and (2) accounting for residential concentrations of TRAP at birth should explain some of the autocorrelation. Several high asthma clusters were observed. Adjusting for TRAP completely explained one cluster; elsewhere, clusters were only partially explained by TRAP. Findings suggest that exposure during early childhood to TRAP in Toronto is an important contributor to the development of the atopic asthma phenotype and reveal the likely importance of other risk factors not measured in the fixed effects of the model.
Plain language summary
Health Canada conducts health risk assessments, under the federal Clean Air Regulatory Agenda, on air pollution emitted from various sources. Traffic-related air pollution has been identified as a risk factor for the development of asthma in children, and exposure in early childhood may be particularly important. Traffic-related air pollution follows geographic patterns according to location of highways and major roadways. These patterns may overlap with patterns for other risk factors for asthma such as socioeconomic status and housing characteristics. Using the Toronto Child Health Evaluation Questionnaire (T-CHEQ) study, a survey of grade 1 and 2 children in the Toronto area, spatial analysis methods were applied to examine the extent to which geographic patterns in traffic-related air pollution and other risk factors explain geographic patterns of asthma prevalence. The study found that traffic-related air pollution partially explained the prevalence of allergic (atopic) asthma. Other unmeasured risk factors may also play a role. This study suggests that traffic-related air pollution exposure in early childhood contributes to the development of allergic asthma in children. Research is also needed to examine the role of other factors, particularly in combination with traffic-related air pollution. These results are supportive of Health Canada's efforts to identify the health threats posed by air pollutants so that informed decisions can be made about how to best limit and control their sources and reduce human exposure. This study was conducted in collaboration with scientists from Wilfrid Laurier University, the University of California - Berkeley, and the Hospital for Sick Children, Toronto.
Subject
- Health,
- Health and safety