Effect of ambient air quality on exacerbation of COPD in patients and its potential mechanism

Abstract

Background

Chronic obstructive pulmonary disease (COPD) is a disease of continuous progress and environmental factors may affect the progress. COPD patients’ activity tolerance and quality of life are associated with air quality. COPD exacerbation from the perspective of geographical air quality has not been reported.

Objectives

To explore environmental effect of two different geographical places on COPD exacerbation and the effect of cigarette smoke extract and carbon particles on bronchial epithelial cell viability.

Methods

Total 139 COPD patients, who lived in Beijing during summer and temporarily migrated to Sanya city in winter, have been enrolled. Respiratory symptoms and lung function data were collected when they were living in Beijing or Sanya, respectively. Effect of cigarette smoke extract plus ultrafine carbon particles on airway epithelial cells were studied.

Measurements and main results

Air pollution as measured by air quality index (AQI) in Beijing summer (113.1±14.2) was significantly worse than that in Sanya winter (49.4±8.9, p<0.001). The COPD Assessment Test (CAT) score was significantly higher in Beijing (26.4±7.1) than that in Sanya (20.0±8.0, p=0.019). Modified Medical Research Council dyspnea scale was also significantly higher in Beijing (2.9±0.9) than that in Sanya (1.9±0.8, p<0.001). FEV₁ was significantly improved when the patients were in Sanya (48.88±24.78%) compared to that in Beijing (41.79±20.06%, p<0.01). Compared with Beijing and Sanya, the relative risk (RR) of hospitalization and acute exacerbation were 1.64 and 3.36, respectively. In vitro study demonstrated that apoptosis of BEAS2B cells in response to cigarette smoke extract plus ultrafine carbon particles (25.50±2.10%) was significantly higher than that of control culture (2.30±1.05%, p<0.01).

Conclusion

These findings suggested that ambient air pollution cause COPD exacerbation, and that air pollutants particle matters induce apoptosis of airway epithelial cells.

Keywords:

• chronic obstructive pulmonary disease
• temporary migration
• air pollution
• lung function
• apoptosis of airway epithelial cells

Acknowledgment

This work was supported by Grant W2013BJ11 from China Healthcare Research Project. The abstract of this paper was presented at the Chest Conference “Effect of ambient air quality on exacerbation of COPD in patients and its potential mechanism” as a poster presentation.

At a glance commentary

Scientific knowledge on the subject

Epidemiological studies have observed association of air pollution and respiratory disease. However, association of air pollution and Chronic Obstructive Pulmonary Disease (COPD) exacerbation from the perspective of geographical air quality difference in the same COPD patients has not been reported.

What this study adds to the field

Results of this study indicated that ambient temperature, humidity and air quality are associated with quality of life in COPD patients.

Author contributions

All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.