Risk of morbidity with stomach cancer among workers employed at radiation-hazardous enterprise

We performed retrospective research among a cohort made up of workers employed at "Mayak" Production Association (Mayak PA), a state nuclear enterprise, who had been exposed to long-term external gamma-irradiation and internal alpha-irradiation caused by plutonium-239 under inhalation introduction. Our research goal was to assess impacts exerted by occupa-tional irradiation and non-radiation factors on a risk of morbidity with stomach cancer (SC) in workers employed at Mayak PA. We used individual data on occupational irradiation doses obtained from "Dosimetric system for Mayak PA workers – 2008" for external gamma-irradiation, and "Dosimetric system for Mayak PA workers – 2013" for internal alpha-irradiation. We applied Poisson regression to calculated odds ratio (OR) for morbidity with stomach cancer among the examined cohort both for radiation and non-radiation factors. We detected statistically significant influence exerted on risk of morbidity with SC among workers employed at Mayak PA by the following factors: age, sex, attitudes towards to smoking and alcohol intake, stomach and duodenum ulcer, and external gamma-irradiation. Taking into account adjustments as per non-radiation factors, we detected a statistically significant increase in OR of morbidity with SC which was equal to 1.48 (95 % CI 1.10; 1.98), when a dose of external gamma-irradiation accumulated in the stomach walls was more than 1.0 Gy. We didn't detect any correlation between risk of morbidity with CS among the examined cohort and internal alpha-irradiation. Given that data obtained in epidemiologic research concerning impacts exerted by occupational irradiation on SC risks are ambiguous, it is necessary to clarify the obtained results and to perform more profound analysis of dose – response relationship among a more extended cohort of workers employed at Mayak PA