Particulate Matter Concentration Linked With Pediatric Asthma Hospital Visits

When particulate matter concentrations were high, patients were more likely to experience asthma exacerbations and likely were also more likely to have reactions to house dust mites.

New research points to particulate matter concentration as a key factor in rates of pediatric asthma exacerbation, and it also shows that interleukin 33 (IL-33) neutralizing antibody can offer protection to these patients.

The report, published in the journal Aging, was based on an analysis of more than 16 million asthma-related health care visits at a Chinese children’s hospital between 2013 and 2017.

Corresponding author Songmin Ying, MD, PhD, of Zhejiang University School of Medicine, and colleagues, noted asthma is a leading cause of childhood emergency department (ED) visits and rates of asthma among children have been growing. One suspected reason for the increase is air pollution, which the authors noted is linked with socioeconomic factors.

“Particulate matter is one of the main components of air pollutants, which is mainly composed of coal combustion, automobile exhaust, dust from construction sites, and smoke from combustions,” Ying and colleagues wrote.

Previous research has pointed to particulate matter as an exacerbating factor in asthma, and studies have also suggested that patients who live in areas with high levels of particulate matter can be more likely to suffer exacerbations as a result of exposure to house dust mites.

The authors wanted to better understand the relationship between particulate matter concentration and asthma, as well as the effects of short-term particulate matter exposure on airway inflammation. They used data from 16,779,739 asthma visits from patients aged 0 to 14 years at the university hospital and evaluated those data against local particulate matter concentration data from the same area.

They found the concentrations of PM2.5 and PM10 (named based on the diameter in micrometers of the particulate matter) showed a moderately positive correlation with ED visits and to the ratio of asthmatic patients among total outpatient and ED visits, noting that other research has suggested that age can impact the effect of particulate matter, particularly PM2.5. They therefore decided to subdivide their cohort into patients younger than age 6 years and those aged 6 or older.

“The results confirmed that in children younger than 6 years old, the correlation between PM concentration and asthma aggravation was more obvious than the older children,” they said.

The investigators extended their research by developing a house dust mite–induced allergic airway inflammation model using mice exposed to particulate matter and a house dust mite challenge. This investigation showed particulate matter aggravated house dust mite–induced airway inflammation, but also that IL-33 neutralizing antibody could play a protective role against such inflammation.

“We confirmed that IL-33 neutralizing antibody could alleviate the aggravated airway inflammation induced by PM exposure in asthmatic mice,” they wrote.

Still, Ying and colleagues cautioned that the effect was protective, meaning its value came when it preceded the allergy challenge. IL-33 antibody did not provide clear alleviation of airway inflammation in mice once the house dust mite–induced inflammation had already occurred, “which might be because the airway inflammation induced by [house dust mites] had basically formed when the IL-33 antibody was administered.”

The investigators said their study provides important new insights into possible avenues by which to prevent asthma exacerbations in children or to protect children already compromised by high particulate matter concentrations.

Reference

Yang X, Zhang Y, Zhan X, et al. Particulate matter exposure is highly correlated to pediatric asthma exacerbation. Aging (Albany NY). Published online July 13, 2021. doi:10.18632/aging.203281