Increased risk of emergency department presentations for bronchiolitis in infants exposed to air pollution

Air pollution has been linked to an increased risk of several respiratory diseases in children, especially respiratory tract infections. The present study aims to evaluate the association between pediatric emergency department (PED) presentations for bronchiolitis and air pollution. PED presentations due to bronchiolitis in children aged less than 1 year were retrospectively collected from 2007 to 2018 in Padova, Italy, together with daily environmental data. A conditional logistic regression based on a time-stratified case-crossover design was performed to evaluate the association between PED presentations and exposure to NO2, PM2.5, and PM10. Models were adjusted for temperature, relative humidity, atmospheric pressure, and public holidays. Delayed effects in time were evaluated using distributed lag non-linear models. Odds ratio for lagged exposure from 0 to 14 days were obtained. Overall, 2251 children presented to the PED for bronchiolitis. Infants' exposure to higher concentrations of PM10 and PM2.5 in the 5 days before the presentation to the PED increased the risk of accessing the PED by more than 10%, whereas high concentrations of NO2 between 2 and 12 days before the PED presentation were associated with an increased risk of up to 30%. The association between pollutants and infants who required hospitalization was even greater. A cumulative effect of NO2 among the 2 weeks preceding the presentation was also observed. In summary, PM and NO2 concentrations are associated with PED presentations and hospitalizations for bronchiolitis. Exposure of infants to air pollution could damage the respiratory tract mucosa, facilitating viral infections and exacerbating symptoms.

Automated summary

Air pollution, specifically higher concentrations of PM10, PM2.5, and NO2, has been found to increase the risk of pediatric emergency department (PED) presentations and hospitalizations for bronchiolitis in children. Exposure to air pollution in the 5 days before PED presentation increases the risk by more than 10%, while exposure to high concentrations of NO2 between 2 and 12 days before PED presentation is associated with an increased risk of up to 30%. Air pollution could damage the respiratory tract mucosa in infants, making them more susceptible to viral infections and worsening symptoms.