Duration versus intensity of exposure on the risk of lung cancer due to radon exposure in the general population

Indoor radon causes lung cancer. The objective of this investigation is to describe lung cancer risk based both on duration and intensity of radon exposure, and to analyze if this effect could be different by sex. To do this, we used pooling information coming from very similar case-control studies on radon and lung cancer, all performed in a radon-priority area. We did a classical categorical analysis using logistic regressions to predict lung cancer risk for exposure duration, intensity of exposure and both variables combined, and we also employed generalized additive models to assess the risk of lung cancer. The results were obtained separately by sex. We included 3415 participants for whom radon measurements had been performed at their home, 1619 of whom were cases. We observed that the length and intensity of residential radon exposure might have a similar importance on lung cancer risk. For those living in dwellings with radon concentrations above 300 Bq/m³, lung cancer risk increases steadily and importantly with exposure duration, even with lengths of exposure above 40 years. We also observed that the risk of lung cancer might be higher in men compared to women. We encourage other researchers to reanalyze their data to confirm these results and also to test if the effect observed in women is replicated.