Air pollution and airway resistance at age 8 years - the PIAMA birth cohort study

Background: Air pollution has been found to adversely affect children's lung function. Forced expiratory volume in 1 s and forced vital capacity from spirometry have been studied most frequently, but measurements of airway resistance may provide additional information. We assessed associations of long-term air pollution exposure with airway resistance.

Methods: We measured airway resistance at age 8 with the interrupter resistance technique (R-int) in participants of the Dutch PIAMA birth cohort study. We linked R-int with estimated annual average air pollution concentrations [nitrogen oxides (NO2, NOx), PM2.5 absorbance ("soot"), and particulate matter <2.5 mu m (PM2.5), <10 mu m (PM10) and 2.5-10 mu m (PMcoarse)] at the birth address and current home address (n = 983). Associations between air pollution exposure and interrupter resistance (R-int) were assessed using multiple linear regression adjusting for potential confounders.

Results: We found that higher levels of NO2 at the current address were associated with higher R-int [adj. mean difference (95% confidence interval) per interquartile range increase in NO2: 0.018 (0.001, 0.035) kPa.s.L-1]. Similar trends were observed for the other pollutants, except, PM10. No association was found between R-int and exposure at the birth address.

Conclusions: Our results support the hypothesis that air pollution exposure is associated with a lower lung function in schoolchildren.