Increased Impact of Air Pollution on Lung Function in Preterm versus Term Infants: The BILD Study.

Infants born prematurely have impaired capacity to deal with oxidative stress shortly after birth. We hypothesize that the relative impact of exposure to air pollution on lung function is higher in preterm than in term infants. In the prospective BILD (Basel-Bern Infant Lung Development) birth cohort of 254 preterm and 517 term infants, we investigated associations of particulate matter ⩽10 μm in aerodynamic diameter (PM) and nitrogen dioxide with lung function at 44 weeks' postconceptional age and exhaled markers of inflammation and oxidative stress response (fractional exhaled nitric oxide [Fe]) in an explorative hypothesis-driven study design. Multilevel mixed-effects models were used and adjusted for known confounders. Significant associations of PM during the second trimester of pregnancy with lung function and Fe were found in term and preterm infants. Importantly, we observed stronger positive associations in preterm infants (born 32-36 wk), with an increase of 184.9 (95% confidence interval [CI], 79.1-290.7) ml/min [Formula: see text]e per 10-μg/m increase in PM, than in term infants (75.3; 95% CI, 19.7-130.8 ml/min) (   = 0.04, after multiple comparison adjustment  = 0.09). Associations of PM and Fe differed between moderate to late preterm (3.4; 95% CI, -0.1 to 6.8 ppb) and term (-0.3; 95% CI, -1.5 to 0.9 ppb) infants, and the interaction with prematurity was significant (   = 0.006,  = 0.036). Preterm infants showed significantly higher susceptibility even to low to moderate prenatal air pollution exposure than term infants, leading to increased impairment of postnatal lung function. Fe results further elucidate differences in inflammatory/oxidative stress response when comparing preterm infants with term infants.