The Relationship between Particulate Matter (PM₁₀) and Hospitalizations and Mortality Of Chronic Obstructive Pulmonary Disease: A Meta-Analysis

BACKGROUND: Numerous studies have reported variable associations between ambient particulate matter (PM) and chronic obstructive pulmonary disease (COPD) hospitalizations and mortality. OBJECTIVE: To conduct a systematic study assessing the associations between hospitalizations and mortality from COPD and ambient PM10 (particulate matter with aerodynamic diameters ≤ 10 μm, PM10). METHODS: Systematic searches were conducted in 6 common electronic databases. A meta-analysis was performed to estimate the odds ratio (OR) to evaluate the relationship between PM10 and COPD hospitalizations and mortality. Publication bias and heterogeneity of samples were tested by Begg funnel plot and Egger test, respectively. Study findings were analyzed using random-effect model and fixed-effect model. RESULTS: The search yielded 31 studies suitable for the meta-analysis during the period from Jan 1, 2000 to Oct 31, 2011. A 10 μg/m(3) increase in PM10 was associated with a 2.7% (95%CI = 1.9%-3.6%) increase in COPD hospitalizations with an OR of 1.027 (95%CI: 1.019-1.036), and a 1.1% (95%CI: 0.8%-1.4%) increase in COPD mortality with an OR of 1.011 (95%CI: 1.008-1.014). CONCLUSIONS: Ambient PM10 is associated with increased COPD hospitalizations and mortality. Further research is needed to elucidate whether this association is causal and to clarify its mechanisms.