Association between exposure to ambient particulate matter and chronic obstructive pulmonary disease: results from a cross-sectional study in China

Abstract

<h3>Objective</h3> The association between exposure to ambient particles with a median aerodynamic diameter less than 10/2.5 µm (particulate matter, PM₁₀/_2.5) and COPD remains unclear. Our study objective was to examine the association between ambient PM₁₀/_2.5 concentrations and lung functions in adults. <h3>Methods</h3> 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 FEV₁/FVC less than 70%. Atmosphere PM sampling was conducted across the clusters along with our survey. <h3>Results</h3> 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 &gt;35 and ≤75 µg/m³ and 2.530 (1.280 to 5.001) for &gt;75 µg/m³ compared with the level of ≤35 µg/m³ for PM_2.5; adjusted OR 2.442 (95% CI 1.449 to 4.117) for &gt;50 and ≤150 µg/m³ compared with the level of ≤50 µg/m³ for PM₁. A 10 µg/m³ increase in PM_2.5 concentrations was associated with a 26 mL (95% CI −43 to −9) decrease in FEV₁, a 28 mL (−49 to −8) decrease in FVC and a 0.09% decrease (−0.170 to −0.010) in FEV₁/FVC ratio. The associations of COPD with PM₁₀ were consistent with PM_2.5 but slightly weaker. <h3>Conclusions</h3> Exposure to higher PM concentrations was strongly associated with increased COPD prevalence and declined respiratory function. <h3>Trial registration number</h3> ChiCTR-OO-14004264; Post-results.