Lung Cancer Risk Attributable to Indoor Radon in a High Radon Potential Region of France

Awareness of the health risks due to exposure to indoor radon has raised concern about its impact in the general population. Using all available epidemiologic results, our goal is to accurately estimate this risk based on data collected in a high radon potential region of France (Franche-Comté). For this study, we considered exposure (response relations derived from cohorts of miners and from joint analyses of residential case) from various control studies. The exposure data come from a representative measurement campaign conducted in Franche-Comté. The estimated number of lung cancer deaths attributable to indoor radon exposure in this region ranges from 72 to 139, depending on the model considered. The attributable risk is higher in granitic area (22 to 39% for 7 to 12 deaths) but the number of deaths is higher in sedimentary area (65 to 127 deaths for 13 to 26%). Although indoor radon concentrations are higher in granitic area, the public health impact is more important in sedimentary area because of higher population density. Introduction The French National Institute of Heath Survey (InVS) recently estimated that 1,000 to 3,000 lung cancer deaths a year may be attributable to radon exposure (Catelinois et al., 2007). In the regions where radon is a potential issue, an accurate assessment of its health impact is important to inform, to sensitize the population and to target actions of risk prevention. According to the French National Radon Measurement Campaign performed between 1984 and 1999, Franche-Comté is a French region particularly concerned with radon. But this nation-wide designed study, relying on measurements realized in volunteers’ houses, may not be the best way to assess with accuracy the number of cancer deaths attributable to radon exposure. In fact, the National Campaign was designed to ensure a homogeneous geographic distribution of the measurements (the country was divided into grids of 40 km) with at least one measurement per grid. Grids that included municipalities with more than 1,500 inhabitants had a second measurement taken in a different location. Volunteers were mainly recruited through contacts in the local governments, which placed and collected the radon detectors. Therefore, data collected in Franche-Comté during this period were not very numerous and perhaps not representative of the various housing types. A more specific design developed for Franche-Comté could be more efficient to assess indoor radon exposure in the region. Objective The first goal of this study was to assess the lung cancer death risk due to indoor radon exposure in Franche-Comté, using a specific radon exposure assessment. A secondary objective was to