Background: Lung function and exacerbations of chronic obstructive pulmonary disease (COPD) have been associated with short-term exposure to air pollution. However, the effect of long-term exposure to particulate matter from industry and traffic on COPD as defined by lung function has not been evaluated so far. Our study was designed to investigate the influence of long-term exposure to air pollution on respiratory symptoms and pulmonary function in 55-year-old women. We especially focused on COPD as defined by GOLD criteria and additionally compared the effects of air pollution on respiratory symptoms by questionnaire data and by lung function measurements.
Methods: In consecutive cross sectional studies conducted between 1985-1994, we investigated 4757 women living in the Rhine-Ruhr Basin of Germany. NO2 and PM10 exposure was assessed by measurements done in an 8 km grid, and traffic exposure by distance from the residential address to the nearest major road using Geographic Information System data. Lung function was determined and COPD was defined by using the GOLD criteria. Chronic respiratory symptoms and possible confounders were defined by questionnaire data. Linear and logistic regressions, including random effects were used to account for confounding and clustering on city level.
Results: The prevalence of COPD (GOLD stages 1-4) was 4.5%. COPD and pulmonary function were strongest affected by PM10 and traffic related exposure. A 7 microg/m3 increase in five year means of PM10 (interquartile range) was associated with a 5.1% (95% CI 2.5%-7.7%) decrease in FEV1, a 3.7% (95% CI 1.8%-5.5%) decrease in FVC and an odds ratio (OR) of 1.33 (95% CI 1.03-1.72) for COPD. Women living less than 100 m from a busy road also had a significantly decreased lung function and COPD was 1.79 times more likely (95% CI 1.06-3.02) than for those living farther away. Chronic symptoms as based on questionnaire information showed effects in the same direction, but less pronounced.
Conclusion: Chronic exposure to PM10, NO2 and living near a major road might increase the risk of developing COPD and can have a detrimental effect on lung function.