Effects of ambient air pollution on lung function growth in Chinese schoolchildren

Objective: To evaluate the adverse effect of exposure to air pollution on lung function growth in school-aged children. Methods: A cohort of 1983 children from three districts in Guangzhou, China was followed-up for 6 months. The children performed pulmonary function tests twice, and their parents reported the child's respiratory symptoms by self-administered questionnaires in both surveys. Results: The annual mean concentrations of air pollutants for the past 5 years for particulate matter less than 10 microns in diameter (PM10), nitrogen (NO2), and sulfur dioxide (SO2) were respectively: 96.1 mu g/m(3), 76.0 mu g/m(3), and 65.7 mu g/m(3) in the highly-polluted district (HPD), 80.3 mu g/m(3), 67.6 mu g/m(3), and 54.5 mu g/m(3) in the moderately-polluted district (MPD), and 80.0 mu g/m(3), 48.1 mu g/m(3), and 52.2 mu g/m(3) in the least-polluted district (LPD). After adjustment for potential confounders, significant deficits were found in the annual growth rates of forced expiratory flows at 25% (FEF25), and between 25% and 75% (FEF25-75) in boys and FEF25 in girls (In boys, for FEF25, -0.136 l/s, p = 0.008 in MPD and -0.153 l/s, p = 0.004 in HPD, respectively; for FEF25-75, -0.176 l/s, p = 0.013 in MPD and -0.167 l/s, p = 0.021 in HPD, respectively. In girls, for FEF25, -0.123 l/s, p = 0.043 in HPD), using LPD as the reference. Deficits in the annual growth rate of forced expiratory volume in 1 s (FEV1) were also negatively associated with air pollution in boys (-0.063 L, p = 0.032 in HPD). Conclusions: The study adds more evidence that exposure to air pollution has adverse effects on lung function growth in schoolchildren. (C) 2010 Elsevier Ltd. All rights reserved.