Cancer mortality in workers at risk of occupational exposure to ionizing radiation in a company in the nuclear sector headquarters in São Paulo

Sep 21, 2026

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Retrospective open historical cohort study compares cancer mortality among workers exposed to gamma and X radiation and the general population of São Paulo, Brazil, and contrasts mortality within monitored versus not monitored work subgroups. Between 2016 and 2021, workers employed from 08/31/1956 to 12/31/2016 were followed using company and official records, calculating standardized mortality ratios by sex, age, and calendar period for cancer groupings. External analysis shows lower mortality (SMR=0.224, 95%CI 0.208–0.240), alongside a healthy worker effect; internal analysis shows SMR=0.685 (95%CI 0.618–0.758).

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Abstract

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[www.scielo.br/rbepid](www.scielo.br/rbepid Revista Brasileira de)[ Revista Brasileira de](www.scielo.br/rbepid Revista Brasileira de) Epidemiologia [https://doi.org/10.1590/1980-549720240011](https://doi.org/10.1590/1980-549720240011) ORIGINAL ARTICLE Cancer mortality in workers at risk of occupational exposure to ionizing radiation ina company in the nuclear sector headquarters in São Paulo Mortalidade por câncer em trabalhadores com risco de exposição ocupacional à radiação ionizante em empresado setor nuclear sediada em São Paulo Glacy Sabra VieiraI , Maria Carmen MartinezII , Maria Regina Alves CardosoIII I Nuclear and Energy Research Institute – São Paulo (SP), Brazil. IIWAF Informática & Saúde Ltda – São Paulo (SP), Brazil. III Universidade de São Paulo, School of Public Health of São Paulo – São Paulo (SP), Brazil. ABSTRACT | Objective: To compare cancer mortality among workers exposed to gamma and X radiation and the general population of the city of São Paulo, as well as that of the subgroup monitored with those not monitored for gamma and X radiation in a work unit with ionizing radiation based in the city of São Paulo. Methods: Between 2016 and 2021, a retrospective open cohort study was carried out with workers who were employed from 08/31/1956 to 12/31/2016 based on data collected at the company and in official institutions. Standardized mortality ratios (SMR) were calculated by sex, age and calendar period of cancers grouped according to type, risk factor and organ system in two analyses: in the external analysis, the mortality of the study population was compared with that of the general population of the city of São Paulo; In the internal analysis, the mortality of the monitored subgroup was compared with that of the subgroup not monitored for gamma and X radiation. Results: The external mortality analysis showed SMR=0 . 224 (95%CI 0.208–0. 240) and the healthy worker effect, while the internal mortality analysis showed SMR=0 .685 (95%CI 0.618–0. 758) . Conclusion: This study showed lower cancer mortality among exposed workers when compared to mortality in the general population and the healthy worker effect. Among workers monitored for gamma and X radiation, cancer mortality was lower when compared to those not monitored. Keywords: Ionizing radiation. Worker. Occupational exposure. Neoplasms., Mortality. Cohort studies. | | --- | | CORRESPONDING AUTHOR: Glacy Sabra Vieira. Avenida Professor Lineu Prestes, 2242, Butantã, CEP: 05508-000, São Paulo (SP), Brasil. E-mail: [gsvieira@ipen.br](gsvieira@ipen.br) | | CONFLICT OF INTERESTS: nothing to declare. | | HOW TO CITE THIS ARTICLE: Vieira GS, Martinez MC, Cardoso MRA. Cancer mortality in workers at risk of occupational exposure to ionizing radiation in a company in the nuclear sector headquarters in São Paulo. Rev Bras Epidemiol. 2024; 27: e240011 . [https://doi.org/10.1590/1980-549720240011](https://doi.org/10.1590/1980-549720240011) | This is an open article distributed under the CC-BY 4.0 license, which allows copying and redistribution of the material in any format and for any purpose as long asthe original authorship and publication credits are maintained. Received on: 07/17/2023 Reviewed on: 11/13/2023 Accepted on: 12/06/2023 Cancer mortality in a worker exposed to ionizing radiation. Rev Bras Epidemiol. 2024; 27: e240011 1 [www.scielo.br/rbepid](www.scielo.br/rbepid) [https://doi.org/10.1590/1980-549720240011](https://doi.org/10.1590/1980-549720240011) INTRODUCTION Ionizing radiation is a carcinogen, and the relationship between exposure dose and cancer risk is linear and limitless1. Safety limits for work are based on populations exposed to single high dose or on patients exposed to high doses of radiotherapy2-4, in addition to experimental studies; but occupational exposure is chronic at low doses. To clarify doubts about the validity of safety limits for work, cohort studies of nuclear industry workers were carried o

FAQs

What is the study objective regarding cancer mortality?

To compare cancer mortality among workers exposed to gamma and X radiation with the general population of São Paulo, and to compare monitored versus not monitored subgroups within the nuclear-sector work unit.

How was the cohort designed and followed?

An open historical cohort followed 6,394 workers from 08/31/1956 until 12/31/2016, with entry at the date workers joined the company and end of follow-up at death or cohort end.

What were the main mortality findings?

External analysis showed SMR=0.224 (95%CI 0.208–0.240) with a healthy worker effect, while internal monitored-vs-not monitored analysis showed SMR=0.685 (95%CI 0.618–0.758), indicating lower cancer mortality in exposed/monitored groups.

Sep 21, 2026

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