Lung Cancer Risk Associated to Exposure to Radon and Smoking in a Case-Control Study of French Uranium Miners

Abstract

A case-control study nested in the cohort of French uranium miners took smoking information into account in investigating the effect of radon exposure on lung cancer risk. This study included 100 miners who died of lung cancer and 500 controls matched for birth period and attained age. Data about radon exposure came from the cohort study, and smoking information was retrospectively determined from a questionnaire and occupational medical records. Smoking status (never vs. ever) was reconstructed for 62 cases and 320 controls. Statistical analyses used conditional logistic regression. The effect of radon exposure on lung cancer risk was assessed with a linear excess relative risk model, and smoking was considered as a multiplicative factor. Mean cumulative radon exposures were 114.75 and 70.84 Working Level Months (WLM) among exposed cases and controls, respectively. The crude excess risk of lung cancer per 100 WLM was 0.98 (95% CI: 0.18-3.08%). When adjusted for smoking, the excess risk was 0.85 per 100 WLM (95% CI: 0.12-2.79%), which is still statistically significant. The relative risk related to smoking was equal to 3.04 (95% CI: 1.20-7.70). This analysis shows a relative risk of lung cancer related to smoking similar to that estimated from previous miners' cohorts. After adjustment for smoking, the effect of radon exposure on lung cancer risk persists, and its estimated risk coefficient is close to that found in the French cohort without smoking information.

Risk of lung cancer from radon exposure: contribution of recently published studies of uranium miners

“…However, a significant increase in the ERR per 100 WLM was noted with increasing number of cigarettes smoked daily (Villeneuve et al, 2007). In a recent French nested case-control study, the ERR for lung cancer related to cumulative radon exposure, adjusted for smoking, was 0.85 per 100 WLM (Leuraud et al, 2007). Adjustment for smoking only led to marginal changes in the risk of lung cancer associated with radon (Leuraud et al, 2007;Schnelzer et al, 2010).…”

DoReMi workshop on multidisciplinary approaches to evaluating cancer risks associated with low-dose internal contamination

“…With respect to potential confounders, information on smoking habits for subgroups of the three cohorts was collected from nested case-control studies on lung cancer (Leuraud et al, 2007;Schnelzer et al, 2010;Leuraud et al, 2011;Tomasek, 2011). Additional information on potential occupational confounders (e.g.…”

Technologically enhanced naturally occurring radioactive materials

“…74 Studies of French uranium miners report an excess 0.71-0.85% risk for lung cancer per 100 working level months. 75,76 Another study reported that uranium miners lose on average of 1.5 years of potential life because of mining related lung cancer or 3 months of life for each year employed as a uranium miner. 77 As with other miners, lung cancer is reportedly the only cancer found to be consistently associated with uranium-mining occupational exposures, and higher radiation exposure tends to increase the relative frequency of squamous cell and small cell lung cancer.…”