Environmental factors and hospitalisation for COPD in a rural county of England

Background: Chronic obstructive pulmonary disease (COPD) is a major global cause of morbidity and mortality. Studies in urban areas have shown associations between air pollutants and hospital admissions for COPD. Whether temporal variations in air quality are associated with hospital admissions for COPD in a rural region with lower concentrations of air pollutants than previously studied was investigated. Methods: Daily COPD admissions were recorded for patients attending three hospitals in the county of Norfolk, UK, between January 2006 and February 2007. Records were combined with daily information on concentrations of six air pollutants (carbon monoxide, nitric oxide, nitrogen dioxide, oxides of nitrogen, ozone and fine particulates), airborne pollens, temperature and influenza incidence. A case–crossover analysis was used to examine the association between air pollution and daily admissions. Results: There were 1050 admissions for COPD over the study period. After adjustment for temperature, pollen and respiratory infections, each 10 µg/m3 increase in CO was associated with a 2% increase in the odds of admission. V3alues of 17%, 22% and 9% were observed for NO, NO2 and oxides of nitrogen respectively. No associations were observed with O3 or particulates. Conclusion: Among a population of a less urbanised area than previously investigated, this study found evidence that ambient pollutant concentrations were still associated with the risks of hospital admission for COPD.