Association of air pollution exposure at birth and in childhood with lung function in preterm-born school-aged children

Abstract

<b>Background:</b> Many studies report the link between air pollution and lung function deficits in childhood and beyond, but there is limited evidence on the effect of pollution on those born preterm, who are already at risk of poorer respiratory health in childhood. <b>Aims and Objectives:</b> We associated pollution levels at birth and at 7-12 years of age when they underwent spirometry in preterm-born (≤34 weeks’ gestation) children. <b>Methods:</b> Lung function measures of FEV₁, FVC, FEV₁/FVC and FEF_25-75% from 543 preterm children born between 2004 and 2011 who took part in the Respiratory Health Outcomes in Neonates (RHiNO) study were associated with pollution levels. Local area levels for PM_2.5, PM₁₀, NO₂ and SO₂ were available annually. Regression models were used to quantify the effect of pollutants after adjustment for bronchopulmonary dysplasia, intrauterine growth restriction and other demographic variables. <b>Results:</b> After modelling, increased PM₁₀ level at birth was significantly associated with a reduced FVC (β -0.53, p=0.033) in a gestationally graded manner. Current PM_2.5 and NO₂ levels were also significantly associated with a reduced FVC (β -1.04, p=0.039; β -0.20, p=0.039 respectively) again in a gestationally graded manner, having the most significant relationship with the 23-28 weeks’ gestation group. There were no significant associations with FEV₁ or FEF_25-75. Significant lung function differences were not seen with SO₂ exposure, either at birth or current. <b>Conclusions:</b> PM₁₀, PM_2.5 and NO₂ at birth were differentially associated with reduced FVC in preterm-born school-aged children, affecting the most preterm group the most.