A recent study found a concerning association between early-life air pollution exposure and an increased incidence of childhood asthma by early and middle childhood. The researchers noted that additional environmental exposures may exacerbate this link.
“By examining multiple periods of exposure and health outcomes, this analysis adds to the growing epidemiologic evidence that early-life air pollution exposures are associated with the onset of childhood asthma,” the researchers emphasized.
Previous studies have also found a correlation between exposure to outdoor air pollution and childhood asthma. However, many of these studies lacked the diversity needed to examine how this association impacts individual and community-level factors.
In this study, researchers aimed to address this gap by examining the association between fine particulate matter (PM2.5) and nitrogen oxide (NO2) exposure and asthma risk during early and middle childhood. They also assessed whether individual and community-level characteristics influence the link between air pollution exposure and asthma.
The study included children enrolled in participating cohorts in the Children’s Respiratory and Environmental Workgroup consortium, located throughout the US and recruited between 1987 and 2007. The researchers collected data on various factors, including mother’s education, parental asthma, smoking during pregnancy, child’s race and ethnicity, sex, and neighborhood characteristics.
Eight of the 12 birth cohorts were included in the analysis, representing a diverse sample of children and their families living throughout the US.
The main outcome measured was a caregiver report of physician-diagnosed asthma at age 4 years and age 11 years. Statistical analysis was performed from February 2022 to December 2023.
“A total of 5279 children were included in the study,” the researchers stated. “One IQR increase in mean NO2 over the first 3 years of life was associated with increased asthma incidence through the first 4 years of life (HR 1.25; 95% CI, 1.03-1.52) and through the first 11 years of life (HR 1.22; 95% CI, 1.04-1.44).”