Pre-natal exposure to NO2 and PM2.5 and newborn lung function: An approach based on repeated personal exposure measurements.

CONTEXT: While strong evidence supports adverse effects of pre-natal air pollution on child's lung function, previous studies rarely considered fine particulate matter (PM2.5) or the potential role of offspring sex and no study examined the effects of pre-natal PM2.5 on the lung function of the newborn. AIM: We examined overall and sex-specific associations of personal pre-natal exposure to PM2.5 and nitrogen (NO2) with newborn lung function measurements. METHODS: This study relied on 391 mother-child pairs from the French SEPAGES cohort. PM2.5 and NO2 exposure was estimated by the average concentration of pollutants measured by sensors carried by the pregnant women during repeated periods of one week. Lung function was assessed with tidal breathing analysis (TBFVL) and nitrogen multiple breath washout (N2MBW) test, performed at 7 weeks. Associations between pre-natal exposure to air pollutants and lung function indicators were estimated by linear regression models adjusted for potential confounders, and then stratified by sex. RESULTS: Mean exposure to NO2 and PM2.5 during pregnancy was 20.2 µg/m3 and 14.3 µg/m3, respectively. A 10 µg/m3 increase in PM2.5 maternal personal exposure during pregnancy was associated with an adjusted 2.5 ml (2.3%) decrease in the functional residual capacity of the newborn (p-value = 0.11). In females, functional residual capacity was decreased by 5.2 ml (5.0%) (p = 0.02) and tidal volume by 1.6 ml (p = 0.08) for each 10 µg/m3 increase in PM2.5. No association was found between maternal NO2 exposure and newborns lung function. CONCLUSIONS: Personal pre-natal PM2.5 exposure was associated with lower lung volumes in female newborns, but not in males. Our results provide evidence that pulmonary effects of air pollution exposure can be initiated in utero. These findings have long term implications for respiratory health and may provide insights into the underlying mechanisms of PM2.5 effects.