Unveiling the intersection of temperature extremes, structural racism, and pediatric asthma exacerbation
Authors:   , Edwards Janelle  R , Schinasi Leah H 
Published: February 2025

Rising temperatures, driven by climate change, are increasingly frequent and intense, disproportionately impacting children with asthma, especially in marginalized communities. Structural racism, both past and present, has relegated these communities to areas burdened with higher pollution, fewer green spaces, and limited health care access. To deepen our understanding of the interconnection between social and environmental factors in asthma exacerbations, we examined disparities in land surface temperature, heatwaves, and temperature variability during the warm/hot season (March- August) for years 2011-2016 in Philadelphia, PA. This dissertation is split into three separate objectives, each of which explored dimensions of climate vulnerability: exposure, adaptive capacity, and sensitivity, by addressing critical gaps in understanding the links between historical redlining, present-day climate vulnerability, and the impact of climate factors on asthma exacerbation. Objective 1 employed an ecological study design to integrate climate vulnerability dimensions (climate exposure and historical adaptive capacity) and estimated the spatial relationships between historical redlining and present-day urban heat islands, while assessing gentrification as a modifying factor. Objectives 2 and 3 focused on the effects of climate factors on a sensitive population, children with asthma. Objective 2 quantified the associations between temperature variation and childhood asthma exacerbations, incorporating individual factors such as race/ethnicity, environmental conditions like air pollution and aeroallergens, and structural factors such as redlining and segregation as modifiers. Lastly, Objective 3 examined the relationship between heatwaves and asthma exacerbations, considering both individual-level modifiers and structural factors, including redlining, segregation, and residence in micro-heat islands. To achieve these objectives, geospatial data and electronic asthma health records from the Children's Hospital of Philadelphia were utilized. Specifically, for Objective 1, spatial regression techniques such as spatial lag, spatial error, and geographically weighted regressions were used to assess the relationship between historical redlining and present-day micro-heat islands. For Objectives 2 and 3, a case-crossover design was employed, using conditional logistic regressions to assess the associations between temperature variability metrics, including interday and intraday variation, and different definitions of heatwaves with pediatric asthma exacerbations. The findings of this dissertation suggest that indicators of past structural racism, such as redlining, may be associated with present-day exposure to micro-heat islands. Additionally, temperature variation appeared to be linked to pediatric asthma exacerbations, with effects potentially modified by factors such as race/ethnicity, residential segregation, and exposure to high counts of tree pollen. Heatwaves may also be associated with pediatric asthma exacerbations; however, the role of both historical and contemporary structural racism as modifiers remains inconclusive, highlighting the need for further research.