Air pollution is associated with a burden of respiratory infections in the first year of life, according to preliminary findings from the Rome IDEaL (Immune Development in Early Life) cohort. Findings from the cohort will be presented during the 2026 Pediatric Academic Societies (PAS) Meeting, April 24-27 in Boston.
Environmental exposures during infancy can affect immune development and respiratory health. While the harms of cigarette smoke are well documented, the broader effects of air pollution on susceptibility to respiratory infections remain poorly defined. The IDEaL Rome cohort (Ospedale Pediatrico Bambino Gesù (OPBG); Rome, Italy), part of a longitudinal study supported by the National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (NIAID) led by Precision Vaccine Program at Children’s Hospital Boston, investigates early life risk factors and immune pathways that contribute to vulnerability to infections, asthma development, and vaccine response. Air pollutants are increasingly recognized as potential disruptors of immune system maturation during critical developmental windows, yet high-quality population data in infants remain limited.
“Our findings from the IDEaL Rome cohort suggest that the air that infants breathe in the first year of life does not just affect their lungs,” said Donato Amodio, MD, PhD, Assistant Professor at OPBG and lead author of the study.
It can fundamentally shape their immune resilience. We found a clear, significant association between common urban pollutants and a higher burden of respiratory infections and wheezing. This research highlights the urgent need for environmental protection to protect our children during their most critical developmental windows.”
Donato Amodio, Ospedale Pediatrico Bambino Gesù
Infants enrolled in the IDEaL Rome cohort underwent clinical assessments at 2, 5, 9, and 12 months, with additional structured follow-ups via telephone interviews. Physician-diagnosed respiratory infections and episodes of wheezing were recorded in a dedicated eCRF. Residential zip codes were linked to the nearest state air quality monitoring station to estimate exposure to particulate matter (PM10), nitrogen oxides (NO2), and nitrogen dioxide (NO2). Cumulative pollutant exposure was calculated for each visit. Pairwise Spearman correlations were assessed between exposure measures and infection outcomes.
Higher cumulative exposure to air pollutants was associated with an increased number of respiratory infections in the first year of life. Significant positive associations were observed for PM10 (r=0.47, p<0.001), NO2 (r=0.39, p<0.001) and NO2 (r=0.39, p<0.001) with total recurrent respiratory infections (RRI). Similar associations were found with wheezing episodes (PM10 r=0.25, NO2 r=0.24, NO2 r=0.23, all p<0.001). Individual infections, including bronchiolitis, bronchitis, acute otitis media, SARS-CoV-2 infection, and tonsillitis, also demonstrated significant but more modest effects (mean r~0.20) (Fig. 1).
The findings support the association and potential role of air pollution in increasing the burden of respiratory infections in early childhood. Incorporating high-resolution environmental monitoring data will improve exposure estimates and help elucidate the mechanisms linking pollutants to impaired infant immune defenses. This work raises the possibility that early environmental health protection can reduce infection vulnerability in infancy.
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