Long term effects of air pollution on lung function in the European Community Respiratory Health Survey (ECRHS)

Lung function is an important measure of respiratory health and a predictor of cardio-respiratory morbidity and mortality. More than fifty publications have addressed long term effects of ambient air pollution on lung function, including several studies on traffic. There is strong support for air pollution effects on lung function growth in children, while in adults the evidence is limited to comparisons of lung function levels and knowledge on effects on lung function decline in adults remains inconclusive. The diversity in study designs and investigated air pollution and lung function measures is high, limiting the comparability of studies and the ability to draw quantitative conclusions.;The association of long term air pollution and lung function has not been studied across adult European multi-national populations. The aim of the European Community Respiratory Health Survey (ECRHS) was to determine the association between long term urban background air pollution and lung function levels, as well as change in lung function among European adults from 21 study centers.;Fine particles (PM2.5) were measured using central monitors. Lung function (FEV1, FVC) was tested at baseline and after nine years of follow-up. Multilevel linear regression models were used to analyze effects on lung function level and change in lung function. No significant associations were found between PM2.5 and any of the spirometric measures. PM2.5, lung function, and numerous covariates were correlated with latitude.;The observed null-findings may be explained by limitations of ECRHS, in particular various aspects of misclassification, and the potential for center-level confounding along latitude. These limitations are inherently associated with the cross-community design, which is a consequence of the central monitor based exposure assessment. To adequately capture urban air pollution contrasts and to avoid confounding by center-level factors, future studies should therefore estimate exposures on an individual or within-community level.;Besides the question of effects on decline there remain several other unresolved lung function topics that require further research, such as early life exposures, effects on the plateau phase, susceptibility factors, and the specific roles of traffic and other pollution sources, among others.