Air pollution during infancy and lung function development into adolescence: The GINIplus/LISA birth cohorts study

Background: Limited evidence exists on how air pollution exposure during infancy, i.e. the first year of life, may affect lung function development into adolescence. Objectives: To investigate the association between exposure to air pollution during the first-year of life and lung function development up to the age of 15 in Germany. Methods: We investigated 915 children from the GINIplus and LISA birth cohorts from Munich (n = 181) and Wesel (n = 734), who had at least two spirometric measurements at ages 6, 10 and 15. Z-scores of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were calculated. Annual average concentrations of nitrogen dioxide, particulate matter with diameters <2.5, <10 and 2.5-10 mu m (PM2.5/10/coarse), and PM2.5 absorbance at home addresses during the first-year of life, were estimated by land-use regression models. Associations between infancy exposure and lung function changes were fitted using multivariable linear mixed models with adjustment for potential confounders. Results: For per interquartile range increase in air pollutants during the first-year life, FEV1 z-scores declined annually by -0.012 (95% confidence interval (CI): -0.014, -0.009) for PM2.5 to -0.023 (95%CI: -0.028, -0.018) for PMcoarse. The declines in FVC were lower than FEV1 [-0.006 (95%CI: -0.008, -0.003) to 0.011 (95%CI: -0.019, -0.003)]. In Munich, the attenuations were only significant for FEV1. Effect estimates of infancy exposure for certain air pollutants were higher for groups with asthma, older maternal age, and breastfeeding <12 weeks than their counterparts. Discussion: Infancy exposure to higher air pollution may reduce lung function development up to adolescence, with airway size more affected than lung volume restriction. The potential modifying effects of maternal age, asthmatic status of children and breastfeeding warrant further exploration.