Researchers of a pooled cohort analysis from the ECHO-PATHWAYS consortium examined whether early-life ambient ozone (O₃) exposure is linked to childhood asthma and wheeze, independently and as part of an air-pollution mixture. The study included 1,188 full-term children with complete address histories from ages 0 to 2 years and caregiver-reported outcomes, using logistic regression and Bayesian kernel machine regression (BKMR) adjusted for child, socioeconomic, and neighborhood factors. Mean O₃ during the first 2 years of life was 26.1 ppb. At ages 4 to 6, 12.3% had current asthma and 15.8% had wheeze. BKMR enabled assessment of joint pollutant effects while accommodating nonlinearity and interactions.
Higher O₃ exposure in the first two years was associated with greater odds of current asthma (odds ratio [OR] per +2 ppb, 1.31; 95% confidence interval [CI], 1.02–1.68) and current wheeze (OR, 1.30; 95% CI, 1.05–1.64) at ages 4 to 6, with BKMR supporting adverse mixture effects. Associations were null at ages 8 to 9 and robust to sensitivity covariate adjustment. These associations were observed despite relatively low regional O₃ levels, suggesting potential early-childhood impacts even where annual concentrations are modest. The age-specific findings point to a sensitive exposure window in the first two years of life, underscoring the value of early prevention and exposure reduction strategies.
Reference: Dearborn LC, Hazlehurst MF, Sherris AR, et al. Early-Life Ozone Exposure and Asthma and Wheeze in Children. JAMA Netw Open. 2025;8(4):e254121. doi: 10.1001/jamanetworkopen.2025.4121.
