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Associations between high ambient temperatures and asthma exacerbation among children in Philadelphia, PA: a time
Leah H Schinasi1,2, Chen C Kenyon3,4, Rebecca A Hubbard5
1Department of Environmental and Occupational Health, Dornsife School of Public Health at Drexel University, Philadelphia, Pennsylvania, USA lhs36@drexel.edu.
Insights
High ambient temperatures increase asthma exacerbation risk in children. This study found a significant association between hot weather and increased asthma events, particularly in younger children and minority groups.
Area of Science:
- Environmental Health
- Pediatric Respiratory Medicine
- Epidemiology
Background:
- Acute asthma exacerbation is a significant cause of childhood morbidity.
- High ambient temperatures are suspected contributors to asthma exacerbations.
Purpose of the Study:
- To quantify the association between hot-season ambient temperatures and asthma exacerbations in children (ages 0-18) in Philadelphia, PA.
- To identify specific age groups and demographic factors that may be more vulnerable to heat-related asthma exacerbations.
Main Methods:
- A time series analysis linked daily asthma exacerbation counts from a children's hospital with daily meteorological data (2011-2016).
- Generalized quasi-Poisson models estimated associations between mean daily temperature (with a 5-day lag) and asthma exacerbation, adjusting for confounders.
- Secondary analyses included adjustments for aeroallergens, air pollutants, and respiratory virus counts.
Main Results:
- High mean daily temperatures (e.g., 33°C vs. 13.1°C) occurring 5 days prior were associated with a 37% increase in asthma exacerbation rates (RR: 1.37, 95% CI 1.04-1.82).
- Associations were strongest in children aged 2 to <5 years.
- Vulnerability was higher among Hispanic and non-Hispanic Black children.
- Adjustments for air pollutants, aeroallergens, and viruses did not significantly alter the temperature-exacerbation association.
Conclusions:
- Ambient heat is linked to increased rates of childhood asthma exacerbation.
- Further research is necessary to elucidate the underlying biological and environmental mechanisms driving these associations.
Objectives:
High ambient temperatures may contribute to acute asthma exacerbation, a leading cause of morbidity in children. We quantified associations between hot-season ambient temperatures and asthma exacerbation in children ages 0-18 years in Philadelphia, PA.
Methods:
We created a time series of daily counts of clinical encounters for asthma exacerbation at the Children's Hospital of Philadelphia linked with daily meteorological data, June-August of 2011-2016. We estimated associations between mean daily temperature (up to a 5-day lag) and asthma exacerbation using generalised quasi-Poisson distributed models, adjusted for seasonal and long-term trends, day of the week, mean relative humidity,and US holiday. In secondary analyses, we ran models with adjustment for aeroallergens, air pollutants and respiratory virus counts. We quantified overall associations, and estimates stratified by encounter location (outpatient, emergency department, inpatient), sociodemographics and comorbidities.
Results:
The analysis included 7637 asthma exacerbation events. High mean daily temperatures that occurred 5 days before the index date were associated with higher rates of exacerbation (rate ratio (RR) comparing 33°C-13.1°C days: 1.37, 95% CI 1.04 to 1.82). Associations were most substantial for children ages 2 to <5 years and for Hispanic and non-Hispanic black children. Adjustment for air pollutants, aeroallergens and respiratory virus counts did not substantially change RR estimates.
Conclusions:
This research contributes to evidence that ambient heat is associated with higher rates of asthma exacerbation in children. Further work is needed to explore the mechanisms underlying these associations.
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