Risk of lung cancer mortality in nuclear workers from internal exposure to alpha particle-emitting radionuclides

Carcinogenic risks of internal exposures to alpha-emitters (except radon) are poorly understood. Since exposure to alpha particles-particularly through inhalation-occurs in a range of settings, understanding consequent risks is a public health priority. The authors aimed to quantify dose-response relationships between lung dose from alpha-emitters and lung cancer in nuclear workers. A case-control study was conducted, nested within Belgian, French, and UK cohorts of uranium and plutonium workers. Cases were workers who died from lung cancer; one to three controls were matched to each. Lung doses from alpha-emitters were assessed using bioassay data. It was estimated excess odds ratio (OR) of lung cancer per gray (Gy) of lung dose. The study comprised 553 cases and 1333 controls. Median positive total alpha lung dose was 2.42mGy (mean: 8.13mGy; maximum: 316mGy); for plutonium the median was 1.27mGy and for uranium 2.17mGy. Excess OR/Gy (90% confidence interval)-adjusted for external radiation, socioeconomic status, and smoking-was 11 (2.6, 24) for total alpha dose, 50 (17, 106) for plutonium, and 5.3 (1.9, 18) for uranium. The authors found strong evidence for associations between low doses from alpha-emitters and lung cancer risk. The excess OR/Gy was greater for plutonium than uranium, though confidence intervals overlap. Risk estimates were similar to those estimated previously in plutonium workers, and in uranium miners exposed to radon and its progeny. Expressed as risk/equivalent dose in sieverts (Sv), the estimates are somewhat larger than but consistent with those for atomic bomb survivors.

Authors: Grellier J, Atkinson W, Bérard P, Bingham D, Birchall A, Blanchardon E, Bull R, Canu Guseva I, Challeton-de Vathaire C, Cockerill R, Do MT, Engels H, Figuerola J, Foster A, Holmstock L, Hurtgen C, Laurier D, Puncher M, Riddell AE, Samson E, Thierry-Chef I, Tirmarche M, Vrijheid M, Cardis E. ;Full Source: Epidemiology. 2017 May 17. doi: 10.1097/EDE.0000000000000684. [Epub ahead of print] ;