Lung cancer mortality in a cohort of population exposed to chronic radiation

Introduction. The paper presents the results of studies aimed at assessing epidemiological risk to the health of the population residing in the territories contaminated as a result of production activity of Production Association “Mayak” in the South Urals.

The objective of the work is to estimate mortality rates from lung cancer (LC) in the population chronically exposed to radiation in the South Urals.

Materials and methods. The South Urals Population Exposed to Radiation (SUPER) Cohort of sixty two thousand five hundred ninety two people (27,789 are men, 34,803 – women) includes all persons exposed to radiation in the South Urals from 1950 to 1960 on the Techa River and the South Urals Radioactive Trace. The follow-up period is 71 years (from 1950 to 2020).

Results. Over a 71-year follow-up period, 925 LC-related death cases have been registered in the cohort in the follow-up territory. The number of person-years at risk was 1,964,140. The results of analyzing the trends in LC mortality rates between 1950 and 2020 showed a statistically significant increase. Both crude and age-standardized mortality rates in men are statistically significantly higher than in women (by a factor of about 13.5). A significant increase in LC mortality rates was found in men from 2016 to 2020 compared to earlier 10-year periods. LC mortality rate among women is increasing slowly and differences by periods are statistically unreliable. Standardized LC mortality rates are statistically significantly higher in the Slavs (predominantly Russians) compared to the Turkic group (Tatars and Bashkirs) over all follow-up periods, except for the last one from 2016 to 2020. Standardized LC mortality rates in the SUPER cohort in smokers are significantly higher compared to non-smokers (more than 20-fold).

Limitations. Relatively high percentage of unknown causes of death in the current study of the analyzed cohort is characterized by a high percentage of the unknown causes of death, as well as of the population lost to follow-up. The latter includes people who migrated from the catchment area and people whose vital status is unknown as of the end of the follow up period. All these factors could decrease the statistical power of the study but would not lower the quality since the exact date of the entry to and exit from the catchment area, the number of person-years and deaths from lung cancer are known for the compared groups.

Conclusion. The analysis of LC mortality rate in the cohort of the exposed population for the period from 1950 to 2020 revealed the following trends, typical for the general population of Russia as well: an increase in LC mortality rate in the recent follow-up years, age-standardized mortality rates are statistically significantly higher in men than in women, in smokers than in non-smokers.

Compliance with ethical standards. Protocol No. 2 of the meeting of the Ethics Committee of the Urals Research Center for Radiation Medicine of the Federal Medical and Biological Agency of Russia dated 02/21/2025.

Conflict of interests. The author declares no conflict of interest.

Acknowledgment. The work was carried out within the framework of the federal target program «Ensuring nuclear and radiation safety for 2016–2020 and for the period until 2030». The author would like to express gratitude to the teams of several departments of the Urals Research Center for Radiation Medicine: to Biophysics laboratory – for the provided dose estimates, to the department Database “Human” for the updated data of the registries of the Urals Research Center for Radiation Medicine medical and dosimetric database, and to the staff of the Epidemiology Laboratory for the preparation of the data for the analysis.

Received: June 21, 2024 / Revised: August 7, 2024 / Accepted: December 3, 2024 / Published: March 31, 2025

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