Association Between Exposure to Ambient Particulate Matter and Chronic Obstructive Pulmonary Disease: Results from a Cross-sectional Study in China

Objective: The association between exposure to ambient particles with a median aerodynamic diameter less than 10/2.5 µm (particulate matter, PM/) and COPD remains unclear. Our study objective was to examine the association between ambient PM/ concentrations and lung functions in adults.

Methods: A cross-sectional study was conducted in southern China. Seven clusters were randomly selected from four cities across Guangdong province. Residents aged ≥20 years in the participating clusters were randomly recruited; all eligible participants were examined with a standardised questionnaire and spirometry. COPD was defined as a post-bronchodilator FEV/FVC less than 70%. Atmosphere PM sampling was conducted across the clusters along with our survey.

Results: Of the subjects initially recruited, 84.4% (n=5993) were included for analysis. COPD prevalence and atmosphere PM concentration varied significantly among the seven clusters. COPD prevalence was significantly associated with elevated PM concentration levels: adjusted OR 2.416 (95% CI 1.417 to 4.118) for >35 and ≤75 µg/m and 2.530 (1.280 to 5.001) for >75 µg/m compared with the level of ≤35 µg/m for PM; adjusted OR 2.442 (95% CI 1.449 to 4.117) for >50 and ≤150 µg/m compared with the level of ≤50 µg/m for PM. A 10 µg/m increase in PM concentrations was associated with a 26 mL (95% CI -43 to -9) decrease in FEV, a 28 mL (-49 to -8) decrease in FVC and a 0.09% decrease (-0.170 to -0.010) in FEV/FVC ratio. The associations of COPD with PM were consistent with PM but slightly weaker.

Conclusions: Exposure to higher PM concentrations was strongly associated with increased COPD prevalence and declined respiratory function.

Trial Registration Number: ChiCTR-OO-14004264; Post-results.