Dissertation
Examining the relationship between residential greenspace and pediatric asthma exacerbation through exposure response, effect modification, mediation, and spatial variation
Doctor of Philosophy (Ph.D.), Drexel University
Mar 2023
DOI:
https://doi.org/10.17918/00001648
Abstract
The presence of greenspace, a characteristic of the built environment that promotes human health, may help prevent asthma exacerbations by reducing air pollution and alleviating stress. This study aims to clarify the relationship between residential greenspace and pediatric asthma exacerbations and inform effective environmental interventions. From 2011-2016, electronic health records were compiled from the Children's Hospital of Philadelphia health care system and linked to residential greenspace measures to establish a cohort of asthmatic children living in the Greater Philadelphia Metropolitan area of Pennsylvania. The relationship between greenspace measures and asthma exacerbations was investigated, as well as the pathways through which they are mediated and modified, and their spatial heterogeneity. There was an inverse association between residential greenspace and childhood asthma exacerbations, and it varied by type of greenspace (i.e., tree canopy, grass/shrub coverage, overall greenness), subgroups of patients (e.g., minority racial and ethnic groups, allergy patients), atmospheric air pollution concentrations, geographical extent (i.e., buffer distances around the child's home), and geographical context (i.e., Philadelphia versus non-Philadelphia). At small buffer distances (250, 500m), higher grass/shrub coverage was associated with 10-18% of lower asthma exacerbations in the non-Philadelphia group, while at larger buffer distances (1000, 2000m), inverse relationships were observed both between tree canopy or grass/shrub coverage and asthma exacerbations in the Philadelphia and non-Philadelphia groups. Asthma exacerbations were modified but not mediated by ambient air pollution levels. When ambient NO2 concentration was high, the highest quartile of tree canopy coverage (within 1000m of children's homes) was associated with a 11% lower incidence of asthma exacerbations (HR=0.89, 95% CI=0.77, 1.02), while on days with low NO2 concentrations, it was linked with a 17% increased incidence (HR=1.17, 95% CI=1.01, 1.35). It did not appear that variations in residential greenspace explained the spatial patterning of asthma exacerbations. Additionally, the relationship between greenspace and asthma exacerbations was not spatially heterogeneous to a statistically significant extent. Results indicate that greenspace type, patient subgroups, regional context, and air pollution play a significant role in greenspace impacts; this information can be incorporated into future planning regarding greenspace installation to improve asthma outcomes for children.
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Details
- Title
- Examining the relationship between residential greenspace and pediatric asthma exacerbation through exposure response, effect modification, mediation, and spatial variation
- Creators
- Yun-Ting Yen
- Contributors
- Anneclaire De Roos (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xii, 173 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Dana and David Dornsife School of Public Health; Drexel University; Environmental and Occupational Health
- Other Identifier
- 991020340714104721