The fraction of lung cancer incidence attributable to fine particulate air pollution in France: Impact of spatial resolution of air pollution models and of information on population density

Abstract

Introduction Outdoor air pollution is a leading environmental cause of death and cancer incidence in humans. We aimed to estimate the fraction of lung cancer incidence attributable to fine particulate matter (PM2.5) exposure in France, and secondarily to illustrate the impact of the spatial resolution of information on air pollution levels and on population density on this estimate. Methods The population attributable fraction (PAF) was estimated using a nationwide spatially refined chemistry-transport model with a 2-km spatial resolution, neighbourhood-scale population density data, and a relative risk from a published meta-analysis. We used the WHO guideline value for PM2.5 exposure (10 μg/m3) as reference and assumed a 10-year time lag between PM2.5 exposure and lung cancer incidence. Lung cancer incidence in adults over 30 years in 2015 was estimated from the cancer registries data. Several sensitivity analyses were conducted which consisted in attributing the nationwide median exposure to all areas, to disregarding population density and to using the 5th percentile of PM2.5 exposure as reference level. Results Population-weighted median exposure to PM2.5 in France in 2005 was 13.8 μg/m3 and 87% of the population was exposed to a level higher than WHO guideline value. In France in 2015, 1466 (or 3.6% of all lung cancer cases) new lung cancer cases were attributable to PM2.5 exposure. The sensitivity analyses demonstrated that disregarding spatial contrasts in PM2.5 exposure or population density would have led to an underestimation of the PAF by up to 7% and 72%, respectively. When the PM2.5 reference level was replaced by the 5th percentile of country-scale exposure (4.9 μg/m3), PAF increased to 7.6%. Conclusions Air pollution plays an important role in the burden of lung cancer in France. Improvements in exposure assessment methods are crucial for the investigation of future health impacts. Policy action to reduce the exposure to PM2.5 such as for instance pollution permits, regulations or subsidies of alternative energy sources may have substantial benefits to reduce the burden of lung cancer in France.