Does lung function growth trajectories depend on prenatal or postnatal exposure to airborne pollutants? - Krakow birth cohort study

摘要

Background: There are variety of factors associated with both the environment and life style, present from prenatal period to adulthood, that may affect or modulate lung function growth. Recent cohort studies showed that spirometry values at 4-6 years of age affect the height of a plateau achieved at age 20-25 years, and hence the starting point for its decline. The aim of this study was to investigate the individual growth trajectories of children's lung functions as they get older by prenatal and postnatal levels of exposure to airborne pollutants, which were both hypothesized to decline studied parameters, with stronger effect of postnatal exposure. Methods: Study group included non-asthmatic, children from birth cohort in Krakow, who went regular spirometry testing at the ages 4 - 9 years. Personal airborne measurement of fine particulate matter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) were performed in the second trimester of pregnancy and this was indicator of prenatal exposure. The same pollutants were reassessed when children where 3 years old with measurement done indoor and outdoor, and were considered as postnatal exposures. Growth trajectories of children's lung functions were adjusted by polynomial multilevel mixed models. All statistical analyses were carried out with STATA13.1. Results: Significant lung function impairment (decrease in both FVC and FEV1) was observed from 4 through 9 years among subjects prenatally exposed to higher levels of prenatal PM2.5 or PAH, however none differences were observed in the rate of increase between lower and higher levels of studied airborne pollutants. Neither PM2.5 nor PAHs levels of postnatal exposure differentiate lung function trajectories is the studied period. Effect of prenatal airborne exposure to pollutants on lung function trajectories remained significant after adjustment to postnatal levels of exposure. Conclusions: Prenatal levels of airborne pollutants might be associated with impaired individual lung growth trajectories, but the impact of postnatal exposure was not observed.