COPD pollution link needs public health action
medwireNews: A study of nearly half a million Canadian residents confirms that exposure to ambient air pollution is associated with a risk for chronic obstructive pulmonary disease (COPD).
The authors also found a previously unreported link between long-term exposure to environmental wood smoke and COPD risk.
Among 467,994 metropolitan Vancouver residents aged 45-85 years without COPD at baseline, 2299 were hospitalized for COPD and 541 died from COPD during 4 years' follow-up.
Wen Qi Gan (Hofstra North Shore-Long Island Jewish School of Medicine, Great Neck, New York, USA) and colleagues found that an interquartile range increase in black carbon levels (0.97 x 105/m) in a resident's area was associated with a 6% increase in the risk for COPD hospitalization and a 7% increase in the risk for COPD mortality.
However, contrary to previous reports, they did not find an association between COPD and small particulate matter, nitric oxide (NO) or nitrogen dioxide (NO2) after adjusting for confounders.
Additionally, the authors found that people living in upper tertile areas in terms of woodsmoke exposure had a 15% greater risk for COPD hospitalization than those living in lower tertile areas. However, there was no effect of woodsmoke exposure on COPD mortality risk.
A Danish cohort study previously reported an association between the risk for COPD and NO2 and NO exposure. However, Gan and colleagues say that black carbon is a better surrogate for traffic-related air pollution as it is emitted directly from vehicle exhausts, whereas NO2 and NO have a number of sources and take on a more homogenous special distribution.
"The null associations might reflect the lack of special variability of these pollutants in this intraurban study," they write in the American Journal of Respiratory and Critical Care Medicine.
Gan and colleagues say that the findings of this large cohort study should help to inform evidence-based policy making and cost-effective air pollution interventions.
"Given the substantial social and economic burden of COPD, ambient air pollution as a widespread environmental risk factor deserves more attention for prevention and control of COPD," the authors conclude.
By Kirsty Oswald, medwireNews Reporter