Air pollution indicators predict outbreaks of asthma exacerbations among elementary school children: integration of daily environmental and school health surveillance systems in Pennsylvania

Air Pollution and Angioedema

OBJECTIVE

To identify environmental factors that may precipitate angioedema.

STUDY DESIGN

Case series with chart review.

SETTING

An urban tertiary care medical center.

SUBJECTS AND METHODS

After institutional review board approval was obtained, a chart review of all patients who presented to Temple University Hospital with angioedema from January 2012 to December 2014 was performed. Patient demographics and hospital course were gathered. Environmental data on the dates of presentation, including precipitation, humidity, and air pollution, were obtained from regional Environmental Protection Agency online data banks and used for statistical analysis.

RESULTS

In total, 408 patients, representing 450 episodes of angioedema, met the inclusion criteria for the study. Most patients were female (58%), African American (74%), and on an angiotensin-converting enzyme inhibitor (ACE-I) upon presentation (61%). Days with unhealthy levels of air pollution were associated with an increased likelihood of angioedema presentation (odds ratio [OR], 1.82; confidence interval [CI], 1.01-3.30; P = .046). Subgroup analysis revealed that elevated ground-level ozone was the primary air pollutant significantly associated with angioedema presentations (OR, 4.95; CI 1.92-12.76; P = .0009). Higher ground-level ozone was also associated with ACE-I angioedema presentations (P = .017) but not with non-ACE-I angioedema presentations (P = .86). Air quality was not predictive of angioedema severity or need for intubation.

CONCLUSION

Angioedema is a complex, multifactorial disease resulting in potentially life-threatening complications. This is the first study to demonstrate that higher levels of air pollution, specifically ground-level ozone, are associated with significantly increased rates of angioedema episodes, although not severity.

Outdoor Environment and Pediatric Asthma: An Update on the Evidence from North America

Introduction. The evidence about the association between asthma and outdoor environmental factors has been inadequate for certain allergens. Even less is known about how these associations vary across seasons and climate regions. We reviewed recent literature from North America for research related to outdoor environmental factors and pediatric asthma, with attention to spatial-temporal variations of these associations. Method. We included indexed literature between years 2010 and 2015 on outdoor environmental factors and pediatric asthma, by searching PubMed. Results. Our search resulted in 33 manuscripts. Studies about the link between pediatric asthma and traffic-related air pollutants (TRAP) consistently confirmed the correlation between TRAP and asthma. For general air pollution, the roles of PM_2.5 and CO were consistent across studies. The link between asthma and O₃ varied across seasons. Regional variation exists in the role of SO₂. The impact of pollen was consistent across seasons, whereas the role of polycyclic aromatic hydrocarbon was less consistent. Discussion. Recent studies strengthened the evidence about the roles of PM_2.5, TRAP, CO, and pollen in asthma, while the evidence for roles of PM_10-2.5, PM₁₀, O₃, NO₂, SO₂, and polycyclic aromatic hydrocarbon in asthma was less consistent. Spatial-temporal details of the environment are needed in future studies of asthma and environment.

Machine learning approaches to personalize early prediction of asthma exacerbations

Patient telemonitoring results in an aggregation of significant amounts of information about patient disease trajectory. However, the potential use of this information for early prediction of exacerbations in adult asthma patients has not been systematically evaluated. The aim of this study was to explore the utility of telemonitoring data for building machine learning algorithms that predict asthma exacerbations before they occur. The study dataset comprised daily self-monitoring reports consisting of 7001 records submitted by adult asthma patients during home telemonitoring. Predictive modeling included preparation of stratified training datasets, predictive feature selection, and evaluation of resulting classifiers. Using a 7-day window, a naive Bayesian classifier, adaptive Bayesian network, and support vector machines were able to predict asthma exacerbation occurring on day 8, with sensitivity of 0.80, 1.00, and 0.84; specificity of 0.77, 1.00, and 0.80; and accuracy of 0.77, 1.00, and 0.80, respectively. Our study demonstrated that machine learning techniques have significant potential in developing personalized decision support for chronic disease telemonitoring systems. Future studies may benefit from a comprehensive predictive framework that combines telemonitoring data with other factors affecting the likelihood of developing acute exacerbation. Approaches implemented for advanced asthma exacerbation prediction may be extended to prediction of exacerbations in patients with other chronic health conditions.

Persistence of serotonergic enhancement of airway response in a model of childhood asthma

The persistence of airway hyperresponsiveness (AHR) and serotonergic enhancement of airway smooth muscle (ASM) contraction induced by ozone (O3) plus allergen has not been evaluated. If this mechanism persists after a prolonged recovery, it would indicate that early-life exposure to O3 plus allergen induces functional changes predisposing allergic individuals to asthma-related symptoms throughout life, even in the absence of environmental insult. A persistent serotonergic mechanism in asthma exacerbations may offer a novel therapeutic target, widening treatment options for patients with asthma. The objective of this study was to determine if previously documented AHR and serotonin-enhanced ASM contraction in allergic monkeys exposed to O3 plus house dust mite allergen (HDMA) persist after prolonged recovery. Infant rhesus monkeys sensitized to HDMA were exposed to filtered air (FA) (n = 6) or HDMA plus O3 (n = 6) for 5 months. Monkeys were then housed in a FA environment for 30 months. At 3 years, airway responsiveness was assessed. Airway rings were then harvested, and ASM contraction was evaluated using electrical field stimulation with and without exogenous serotonin and serotonin-subtype receptor antagonists. Animals exposed to O3 plus HDMA exhibited persistent AHR. Serotonin exacerbated the ASM contraction in the exposure group but not in the FA group. Serotonin subtype receptors 2, 3, and 4 appear to drive the response. Our study shows that AHR and serotonin-dependent exacerbation of cholinergic-mediated ASM contraction induced by early-life exposure to O3 plus allergen persist for at least 2.5 years and may contribute to a persistent asthma phenotype.