New evidence on air pollution and lung cancer
A recent article in the Lancet Oncology presents findings from individuals across Europe showing that exposure to particulate matter air pollution increased the risk of lung cancer. The study was developed as part of the EU funded ESCAPE project on long-term effects on human health of exposure to air pollution in Europe.
The design of the study is sophisticated and overcame several limitations of previous air pollution studies. Whereas earlier studies examined the effect of air pollution on lung cancer by assessing geographical correlations and shifted to individual studies with area-level exposure assessments, Raaschou-Nielsen and colleagues (researchers of the study) took it a step further by combining effects estimates from 17 cohorts with standardized protocols and meta-analysis. This increased the number of participants, who came from a wide range of European regions, and reduced the possibility of sampling and publication bias.
This study also benefited from a high follow-up rate and adjustment of potential confounders, including a set of smoking variables. Therefore the study should have reduced much of the systemic and random errors reported previously.
Even in the well-known textbooks for medical doctors, air pollution is not listed as a cause of lung cancer. Although smoking is of course a strong risk factor, evidence for an association between air pollution exposure and lung cancer is also accumulating. The lung cancer risk associated with air pollution is much lower than that associated with smoking but everybody is still exposed to air pollution. The public health effect is therefore quite large and the WHO has estimated that smoking caused 1 million deaths and 71% of lung cancer worldwide in 2004, whereas air pollution caused 1.2 million deaths and 8% of lung cancer worldwide in the same year.
Even at current concentrations, we might have to add air pollution, to the list of causes of lung cancer and recognise that air pollution has large effects on public health, although fortunately, like tobacco smoking, it is a controllable factor.
Article in: The Lancet Oncology, Volume 14, Issue 9, Pages 788 - 789, August 2013, Published Online: 10 July 2013, copyright © 2013 Elsevier Ltd All rights reserved.
Last updated on 8 October 2013