Children exposed to just 2ppb increases in ambient ozone during their first 2 years of life had over 30% higher odds of developing asthma and wheeze by age 6, according to a recent study.
Researchers recently reported that early-life exposure to ozone (O₃) may be associated with increased odds of asthma and wheeze in early childhood. The findings, published in JAMA Network Open, were based on a multisite analysis across six U.S. cities using data from the prospective ECHO-PATHWAYS consortium; the research team was led by Logan C. Dearborn, MPH, of the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle.
The team evaluated 1,188 children with complete airway surveys and geocoded residential histories from birth to age 2 years—a period identified as a critical window for respiratory development. Using a validated point-based spatiotemporal model, the researchers estimated ambient O₃ concentrations at each child’s residential address, averaging exposure across the first 2 years of life. Mean ambient O₃ concentration was 26.1 parts per billion (ppb). Outcomes of interest—caregiver-reported asthma and wheeze—were assessed at ages 4 to 6 years (primary) and again at ages 8 to 9 years (secondary), using standardized items from the International Study of Asthma and Allergies in Childhood questionnaire.
At the age 4 to 6 assessment, 148 children (12.3%) had current asthma and 190 (15.8%) had current wheeze. After adjusting for key covariates, including maternal education, asthma history, secondhand smoke exposure, and neighborhood deprivation index, a 2-ppb increase in O₃ was associated with 31% higher odds of asthma and 30% higher odds of wheeze. Bayesian kernel machine regression analysis further supported a linear association between O₃ and asthma when nitrogen dioxide and fine particulate matter concentrations were held at median levels, although no significant overall mixture effects were identified for wheeze.
At age 8 to 9, early-life O₃ exposure was not significantly associated with strict asthma or wheezing phenotypes, including early, late, or persistent wheeze. Sensitivity analyses adjusting for prenatal and postnatal copollutants and excluding individual cohorts yielded attenuated but directionally consistent estimates.
These results suggest that even in regions with relatively low ambient O₃ levels, postnatal exposure may increase the risk for asthma and wheeze in early childhood. The researchers emphasized the importance of ongoing investigation into early-life environmental exposures and their role in pediatric respiratory health.
Full disclosures can be found in the published study.
Source: JAMA Network Open
