Increased impact of air pollution on lung function in preterm vs. term infants: the BILD study

Introduction: Infants born prematurely have impaired capacity to deal with oxidative stress shortly after birth. We hypothesize that the relative impact of pre- and postnatal exposure to air pollution on postnatal lung function is higher in preterm than in term infants. Methods: In the prospective Basel-Bern infant lung development (BILD) cohort of 771 infants, 254 preterm and 517 term, we investigated the associations of pre- and postnatal air pollution levels for particulate matter with a diameter <10µm (PM10) and nitrogen dioxide (NO2) with postnatal lung function (tidal breathing flow volume loops) at 44 weeks postconceptional age and exhaled surrogate markers of inflammation and oxidative stress response (fraction of exhaled nitric oxide (FeNO)). Multilevel mixed-effects linear regression was used and adjusted for known confounders and study center. Main Results: Significant negative associations of PM10 during the second trimester of pregnancy with lung function and FeNO were found in term and preterm infants. Importantly, we observed stronger associations in moderate to late preterm infants (32-37 weeks), with an increase of [184.9 (79.1 – 290.7) mL/min] minute ventilation per 10 µg/m3 increase in PM10 (pprematurity × PM10 interaction = 0.04). Associations of air pollution and FeNO differed significantly between preterm and term infants (pprematurity × PM10 interaction = 0.006). Conclusion: Preterm infants showed significant higher susceptibility to air pollution exposure during pregnancy than term infants, leading to increased impairment of postnatal lung function. FeNO results further elucidate differences in inflammatory/oxidative stress response comparing preterm to term infants.