nuclear-news

Huge study of nuclear workers in France, the United Kingdom, and the United States confirms low dose radiation as a cause of cancer.

Cancer mortality after low dose exposure to ionising radiation in workers in France, the United Kingdom, and the United States (INWORKS): cohort study

BMJ 2023; 382 doi: https://doi.org/10.1136/bmj-2022-074520 (Published 16 August 2023)Cite this as: BMJ 2023;382:e074520

David B Richardson, professor1,   Klervi Leuraud, head of service2,   Dominique Laurier, deputy director of health2,   Michael Gillies, medical statistician3,   Richard Haylock, senior research scientist3,   Kaitlin Kelly-Reif, senior research scientist4,   Stephen Bertke, research statistician4,   Robert D Daniels, senior research scientist4,   Isabelle Thierry-Chef, senior research scientist5,   Monika Moissonnier, research assistant6,   Ausrele Kesminiene, senior visiting scientist6,   Mary K Schubauer-Berigan, programme head6

Abstract

Objective To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer.

Design Multinational cohort study.

Setting Cohorts of workers in the nuclear industry in France, the UK, and the US included in a major update to the International Nuclear Workers Study (INWORKS).

Participants 309 932 workers with individual monitoring data for external exposure to ionising radiation and a total follow-up of 10.7 million person years.

Main outcome measures Estimates of excess relative rate per gray (Gy) of radiation dose for mortality from cancer.

Results The study included 103 553 deaths, of which 28 089 were due to solid cancers. The estimated rate of mortality due to solid cancer increased with cumulative dose by 52% (90% confidence interval 27% to 77%) per Gy, lagged by 10 years. Restricting the analysis to the low cumulative dose range (0-100 mGy) approximately doubled the estimate of association (and increased the width of its confidence interval), as did restricting the analysis to workers hired in the more recent years of operations when estimates of occupational external penetrating radiation dose were recorded more accurately. Exclusion of deaths from lung cancer and pleural cancer had a modest effect on the estimated magnitude of association, providing indirect evidence that the association was not substantially confounded by smoking or occupational exposure to asbestos.

Conclusions This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world’s most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings.

Conclusions This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world’s most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings.

…………………………………………………………………………………………………………………………………………………………………………………………………………………………… Discussion

This study, which involved a major update to an international cohort mortality study of radiation dosimeter monitored workers, reports evidence of an increase in the excess relative rate of solid cancer mortality with increasing cumulative exposure to ionising radiation at the low dose rates typically encountered by French, UK, and US nuclear workers. The study provides evidence in support of a linear association between protracted low dose external exposure to ionising radiation and solid cancer mortality. 

…………………………………………………

What is already known on this topic  

• Ionising radiation is an established cause of cancer
• The primary quantitative basis for radiation protection standards comes from studies of people exposed to acute, high doses of ionising radiation

What this study adds

• The results of an updated study of nuclear workers in France, the UK, and the US suggest a linear increase in the relative rate of cancer with increasing exposure to radiation
• Some evidence suggested a steeper slope for the dose-response association at lower doses than over the full dose range
• The risk per unit of radiation dose for solid cancer was larger in analyses restricted to the low dose range (0-100 mGy) and to workers hired in the more recent years of operations

more https://www.bmj.com/content/382/bmj-2022-074520?fbclid=IwAR2zEZMejFSss68iOHNDBfzmnUMLBWGRuc9IRFhlWHoujUzQnQe-452Wx38—

August 19, 2023 - Posted by Christina Macpherson | employment, radiation, Reference