Impact of ambient air pollution on lung function in preterm-born school-aged children

Increased outdoor air pollution worsens lung function in children. However, these associations are less well studied in preterm-born individuals.

We assessed associations between ambient air pollutants and spirometry measures in preterm-born children.

The Respiratory Health Outcomes in Neonates study recruited preterm-born children aged 7-12 years who were born at ≤34 week's gestation. We associated four ambient air pollutants (particulate matter with aerodynamic diameter ≤2.5 µm (PM_2.5), PM₁₀, nitrogen dioxide (NO₂) and sulfur dioxide) at time of birth and spirometry assessment and averaged exposure between these two time points with spirometry measures, using linear regression analyses. Gestational age was banded into 23-28, 29-31 and 32-34 week's. Regression models estimated spirometry values against pollutant levels at birth and at the time of spirometry.

From 565 preterm-born children, 542 (96%) had satisfactory data. After adjustments for early and current life factors, significant detrimental associations were noted between PM₁₀ at birth and per cent predicted forced vital capacity (%FVC) for the 23-28 and 29-31 week's gestation groups and between current PM_2.5 and NO₂ exposure and %FVC for the 23-28 week's gestation group. No associations with spirometry were noted for the averaged pollution exposure between birth and spirometry. Predictive models showed 5.9% and 7.4% differences in %FVC between the highest and lowest current pollution exposures for PM_2.5 and NO_2, respectively, in the 23-28 week group.

Birth and current exposures to road-traffic-associated pollutants detrimentally affected %FVC in preterm-born school-aged children, who already have compromised lung function.