1
|
Little MP, Bazyka D, de Gonzalez AB, Brenner AV, Chumak VV, Cullings HM, Daniels RD, French B, Grant E, Hamada N, Hauptmann M, Kendall GM, Laurier D, Lee C, Lee WJ, Linet MS, Mabuchi K, Morton LM, Muirhead CR, Preston DL, Rajaraman P, Richardson DB, Sakata R, Samet JM, Simon SL, Sugiyama H, Wakeford R, Zablotska LB. A Historical Survey of Key Epidemiological Studies of Ionizing Radiation Exposure. Radiat Res 2024; 202:432-487. [PMID: 39021204 PMCID: PMC11316622 DOI: 10.1667/rade-24-00021.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/23/2024] [Indexed: 07/20/2024]
Abstract
In this article we review the history of key epidemiological studies of populations exposed to ionizing radiation. We highlight historical and recent findings regarding radiation-associated risks for incidence and mortality of cancer and non-cancer outcomes with emphasis on study design and methods of exposure assessment and dose estimation along with brief consideration of sources of bias for a few of the more important studies. We examine the findings from the epidemiological studies of the Japanese atomic bomb survivors, persons exposed to radiation for diagnostic or therapeutic purposes, those exposed to environmental sources including Chornobyl and other reactor accidents, and occupationally exposed cohorts. We also summarize results of pooled studies. These summaries are necessarily brief, but we provide references to more detailed information. We discuss possible future directions of study, to include assessment of susceptible populations, and possible new populations, data sources, study designs and methods of analysis.
Collapse
Affiliation(s)
- Mark P. Little
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
- Faculty of Health and Life Sciences, Oxford Brookes University, Headington Campus, Oxford, OX3 0BP, UK
| | - Dimitry Bazyka
- National Research Center for Radiation Medicine, Hematology and Oncology, 53 Melnikov Street, Kyiv 04050, Ukraine
| | | | - Alina V. Brenner
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Vadim V. Chumak
- National Research Center for Radiation Medicine, Hematology and Oncology, 53 Melnikov Street, Kyiv 04050, Ukraine
| | - Harry M. Cullings
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Robert D. Daniels
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Benjamin French
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric Grant
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194, Japan
| | - Michael Hauptmann
- Institute of Biostatistics and Registry Research, Brandenburg Medical School Theodor Fontane, 16816 Neuruppin, Germany
| | - Gerald M. Kendall
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Headington, Oxford, OX3 7LF, UK
| | - Dominique Laurier
- Institute for Radiological Protection and Nuclear Safety, Fontenay aux Roses France
| | - Choonsik Lee
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Won Jin Lee
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, South Korea
| | - Martha S. Linet
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Kiyohiko Mabuchi
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Lindsay M. Morton
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | | | | | - Preetha Rajaraman
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - David B. Richardson
- Environmental and Occupational Health, 653 East Peltason, University California, Irvine, Irvine, CA 92697-3957 USA
| | - Ritsu Sakata
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Jonathan M. Samet
- Department of Epidemiology, Colorado School of Public Health, Aurora, Colorado, USA
| | - Steven L. Simon
- Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA
| | - Hiromi Sugiyama
- Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan
| | - Richard Wakeford
- Centre for Occupational and Environmental Health, The University of Manchester, Ellen Wilkinson Building, Oxford Road, Manchester, M13 9PL, UK
| | - Lydia B. Zablotska
- Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, 550 16 Street, 2 floor, San Francisco, CA 94143, USA
| |
Collapse
|
2
|
Lee D, Cha ES, Park S, Sung H, Noh E, Jeong H, Jang WI, Seo S. Cohort Profile: The Korean Radiation Workers Study (KRWS). Int J Epidemiol 2024; 53:dyae060. [PMID: 38628072 DOI: 10.1093/ije/dyae060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Affiliation(s)
- Dalnim Lee
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Eun Shil Cha
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Soojin Park
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Hyoju Sung
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Eunbi Noh
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Haesu Jeong
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Won-Il Jang
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
- Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Songwon Seo
- National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| |
Collapse
|
3
|
Saenko V, Mitsutake N. Radiation-Related Thyroid Cancer. Endocr Rev 2024; 45:1-29. [PMID: 37450579 PMCID: PMC10765163 DOI: 10.1210/endrev/bnad022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 04/18/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
Radiation is an environmental factor that elevates the risk of developing thyroid cancer. Actual and possible scenarios of exposures to external and internal radiation are multiple and diverse. This article reviews radiation doses to the thyroid and corresponding cancer risks due to planned, existing, and emergency exposure situations, and medical, public, and occupational categories of exposures. Any exposure scenario may deliver a range of doses to the thyroid, and the risk for cancer is addressed along with modifying factors. The consequences of the Chornobyl and Fukushima nuclear power plant accidents are described, summarizing the information on thyroid cancer epidemiology, treatment, and prognosis, clinicopathological characteristics, and genetic alterations. The Chornobyl thyroid cancers have evolved in time: becoming less aggressive and driver shifting from fusions to point mutations. A comparison of thyroid cancers from the 2 areas reveals numerous differences that cumulatively suggest the low probability of the radiogenic nature of thyroid cancers in Fukushima. In view of continuing usage of different sources of radiation in various settings, the possible ways of reducing thyroid cancer risk from exposures are considered. For external exposures, reasonable measures are generally in line with the As Low As Reasonably Achievable principle, while for internal irradiation from radioactive iodine, thyroid blocking with stable iodine may be recommended in addition to other measures in case of anticipated exposures from a nuclear reactor accident. Finally, the perspectives of studies of radiation effects on the thyroid are discussed from the epidemiological, basic science, and clinical points of view.
Collapse
Affiliation(s)
- Vladimir Saenko
- Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| | - Norisato Mitsutake
- Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| |
Collapse
|
4
|
Gudzenko N, Mabuchi K, Brenner AV, Little MP, Hatch M, Drozdovitch V, Vij V, Chumak V, Bakhanova E, Trotsyuk N, Kryuchkov V, Golovanov I, Bazyka D, Cahoon EK. Risk of thyroid cancer in Ukrainian cleanup workers following the Chornobyl accident. Eur J Epidemiol 2022; 37:67-77. [PMID: 34897585 PMCID: PMC10655930 DOI: 10.1007/s10654-021-00822-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 11/18/2021] [Indexed: 10/19/2022]
Abstract
Although much is known about the radiation-related risk of thyroid cancer in those exposed at young ages, less is known about the risk due to adult exposure, particularly in men. We aimed to examine the association between thyroid radiation dose received during adulthood and thyroid cancer risk in men. We conducted a nested case-control study (149 cases; 458 controls) of male, Ukrainian cleanup workers who first worked in the Chornobyl zone between ages 18 and 59 years, with cases identified through linkage with the National Cancer Registry of Ukraine from 1988 to 2012. Individual thyroid doses due to external and internal exposure during the cleanup mission and during residence in contaminated settlements were estimated (total dose mean 199 mGy; range 0.15 mGy to 9.0 Gy). The excess odds ratio per gray (EOR/Gy) for overall thyroid cancer was 0.40 (95% CI: - 0.05, 1.48; p-value = 0.118). Time since exposure was borderline significant (p-value = 0.061) in modifying this association so that less time since exposure was associated with a stronger EOR/Gy. An elevated, but nonsignificant association was observed for follicular thyroid cancer (EOR/Gy = 1.72; 95% CI: - 0.25, 13.69; p-value = 0.155) based on a small number of cases (n = 24). Our findings for radiation-related overall thyroid cancer risk are consistent with evidence of increased risks observed in most of the other studies of adult exposure, though the magnitude of the effect in this study is lower than in the previous case-control study of Chornobyl cleanup workers.
Collapse
Affiliation(s)
- Natalia Gudzenko
- National Research Centre for Radiation Medicine, Kyiv, 04050, Ukraine
| | - Kiyohiko Mabuchi
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA
| | | | - Mark P Little
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA
| | - Maureen Hatch
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA
| | - Vladimir Drozdovitch
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA
| | - Vibha Vij
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA
| | - Vadim Chumak
- National Research Centre for Radiation Medicine, Kyiv, 04050, Ukraine
| | - Elena Bakhanova
- National Research Centre for Radiation Medicine, Kyiv, 04050, Ukraine
| | - Natalia Trotsyuk
- National Research Centre for Radiation Medicine, Kyiv, 04050, Ukraine
| | - Victor Kryuchkov
- Burnasyan Federal Medical and Biophysical Centre, 46 Zhivopisnaya Street, Moscow, 123182, Russia
| | - Ivan Golovanov
- Burnasyan Federal Medical and Biophysical Centre, 46 Zhivopisnaya Street, Moscow, 123182, Russia
| | - Dimitry Bazyka
- National Research Centre for Radiation Medicine, Kyiv, 04050, Ukraine
| | - Elizabeth K Cahoon
- Radiation Epidemiology Branch, DCEG, Division of Cancer Epidemiology and Genetics, NIH, DHHS, National Cancer Institute, 9609 Medical Center Dr., Rm 7E542, Bethesda, MD, MS 9778, USA.
| |
Collapse
|
5
|
Visweswaran S, Raavi V, Abdul Syed Basheerudeen S, Kanagaraj K, Prasad A, Selvan Gnana Sekaran T, Pattan S, Shanmugam P, Ozimuthu A, Joseph S, Perumal V. Comparative analysis of physical doses and biomarker changes in subjects underwent Computed Tomography, Positron Emission Tomography-Computed Tomography, and interventional procedures. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2021; 870-871:503404. [PMID: 34583824 DOI: 10.1016/j.mrgentox.2021.503404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/30/2021] [Accepted: 09/11/2021] [Indexed: 10/20/2022]
Abstract
Even though the medical uses of ionizing radiation are well-acknowledged globally as vital tools for the improvement of human health, they also symbolize the major man-made sources of radiation exposure to the population. Estimation of absorbed dose and biological changes after radiation-based imaging might help to better understand the effects of low dose radiation. Because of this, we measured the Entrance Surface Dose (ESD) at different anatomical locations using Lithium tetraborate doped with manganese (Li2B4O7: Mn), recorded Dose Length Product (DLP) and Dose Area Product (DAP), analyzed Chromosomal Aberration (CA), Micronucleus (MN), gamma-H2AX (γ-H2AX), and p53ser15 proteins in the blood lymphocytes of patients (n = 267) underwent Computed Tomography (CT), Positron Emission Tomography-CT (PET/CT), and interventional procedures and healthy volunteers (n = 19). The DLP and effective doses obtained from PET/CT procedures were significantly higher (p < 0.05) when compared to CT. Fluoroscopic time and DAP were significantly higher (p < 0.05) in therapeutic compared to diagnostic interventional procedures. All the anatomical locations registered a significant amount of ESD, the ESD obtained from CT and interventional procedures were significantly (p < 0.05) higher when compared to PET/CT. Fluoroscopic time did not correlate with the ESD (eye, head, thyroid, and shoulder; R2 = 0.03). CA frequency after PET/CT was significantly higher (p < 0.001) when compared to CT and interventional procedures. MN frequency was significantly higher in 24-hs (p < 0.001) post-interventional procedure compared to 2-hs. The mean ± SD of mean fluorescence intensity of γ-H2AX and p53ser15 obtained from all subjects underwent PET/CT and interventional procedures did not show a significant difference (p > 0.05) between pre- and post-procedure. However, the relative fluorescence intensity of γ-H2AX and p53ser15 was >1 in 58.5 % and 65.8 % of subjects respectively. Large inter-individual variation and lack of correlation between physical dose and biomarkers suggest the need for robust dosimetry with a large sample size to understand the health effects of low dose radiation.
Collapse
Affiliation(s)
- Shangamithra Visweswaran
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Venkateswarlu Raavi
- Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education and Research (Deemed to be University), Tamaka, Kolar, Karnataka, 563 103, India
| | - Safa Abdul Syed Basheerudeen
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Karthik Kanagaraj
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Akshaya Prasad
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Tamizh Selvan Gnana Sekaran
- Central Research Lab, K.S. Hegde Medical Academy, NITTE (Deemed to be University), Mangalore, Karnataka, 575 018, India
| | - Sudha Pattan
- Department of Radiology & Imaging Sciences, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Panneerselvam Shanmugam
- Department of Radiology & Imaging Sciences, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Annalakshmi Ozimuthu
- Safety, Quality & Resource Management Group, Health Safety and Environment Group, Homi Bhabha National Institute, Indira Gandhi Center for Atomic Research, Kalpakkam, Tamil Nadu, 603 102, India
| | - Santhosh Joseph
- Department of Neuro-Radiology, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India
| | - Venkatachalam Perumal
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research (Deemed to be University), Porur, Chennai, Tamil Nadu, 600 116, India.
| |
Collapse
|
6
|
Harbron RW, Pasqual E. Ionising radiation as a risk factor for lymphoma: a review. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2020; 40:R151-R185. [PMID: 33017815 DOI: 10.1088/1361-6498/abbe37] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
The ability of ionising radiation to induce lymphoma is unclear. Here, we present a narrative review of epidemiological evidence of the risk of lymphoma, including chronic lymphocytic leukaemia (CLL) and multiple myeloma (MM), among various exposed populations including atomic bombing survivors, industrial and medical radiation workers, and individuals exposed for medical purposes. Overall, there is a suggestion of a positive dose-dependent association between radiation exposure and lymphoma. The magnitude of this association is highly imprecise, however, with wide confidence intervals frequently including zero risk. External comparisons tend to show similar incidence and mortality rates to the general population. Currently, there is insufficient information on the impact of age at exposure, high versus low linear energy transfer radiation, external versus internal or acute versus chronic exposures. Associations are stronger for males than females, and stronger for non-Hodgkin lymphoma and MM than for Hodgkin lymphoma, while the risk of radiation-induced CLL may be non-existent. This broad grouping of diverse diseases could potentially obscure stronger associations for certain subtypes, each with a different cell of origin. Additionally, the classification of malignancies as leukaemia or lymphoma may result in similar diseases being analysed separately, while distinct diseases are analysed in the same category. Uncertainty in cell of origin means the appropriate organ for dose response analysis is unclear. Further uncertainties arise from potential confounding or bias due to infectious causes and immunosuppression. The potential interaction between radiation and other risk factors is unknown. Combined, these uncertainties make lymphoma perhaps the most challenging malignancy to study in radiation epidemiology.
Collapse
Affiliation(s)
- Richard W Harbron
- Population Health Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, United Kingdom
- Barcelona Institute for Global Health, (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Elisa Pasqual
- Barcelona Institute for Global Health, (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| |
Collapse
|
7
|
Hauptmann M, Daniels RD, Cardis E, Cullings HM, Kendall G, Laurier D, Linet MS, Little MP, Lubin JH, Preston DL, Richardson DB, Stram DO, Thierry-Chef I, Schubauer-Berigan MK, Gilbert ES, Berrington de Gonzalez A. Epidemiological Studies of Low-Dose Ionizing Radiation and Cancer: Summary Bias Assessment and Meta-Analysis. J Natl Cancer Inst Monogr 2020; 2020:188-200. [PMID: 32657347 PMCID: PMC8454205 DOI: 10.1093/jncimonographs/lgaa010] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 03/26/2020] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND Ionizing radiation is an established carcinogen, but risks from low-dose exposures are controversial. Since the Biological Effects of Ionizing Radiation VII review of the epidemiological data in 2006, many subsequent publications have reported excess cancer risks from low-dose exposures. Our aim was to systematically review these studies to assess the magnitude of the risk and whether the positive findings could be explained by biases. METHODS Eligible studies had mean cumulative doses of less than 100 mGy, individualized dose estimates, risk estimates, and confidence intervals (CI) for the dose-response and were published in 2006-2017. We summarized the evidence for bias (dose error, confounding, outcome ascertainment) and its likely direction for each study. We tested whether the median excess relative risk (ERR) per unit dose equals zero and assessed the impact of excluding positive studies with potential bias away from the null. We performed a meta-analysis to quantify the ERR and assess consistency across studies for all solid cancers and leukemia. RESULTS Of the 26 eligible studies, 8 concerned environmental, 4 medical, and 14 occupational exposure. For solid cancers, 16 of 22 studies reported positive ERRs per unit dose, and we rejected the hypothesis that the median ERR equals zero (P = .03). After exclusion of 4 positive studies with potential positive bias, 12 of 18 studies reported positive ERRs per unit dose (P = .12). For leukemia, 17 of 20 studies were positive, and we rejected the hypothesis that the median ERR per unit dose equals zero (P = .001), also after exclusion of 5 positive studies with potential positive bias (P = .02). For adulthood exposure, the meta-ERR at 100 mGy was 0.029 (95% CI = 0.011 to 0.047) for solid cancers and 0.16 (95% CI = 0.07 to 0.25) for leukemia. For childhood exposure, the meta-ERR at 100 mGy for leukemia was 2.84 (95% CI = 0.37 to 5.32); there were only two eligible studies of all solid cancers. CONCLUSIONS Our systematic assessments in this monograph showed that these new epidemiological studies are characterized by several limitations, but only a few positive studies were potentially biased away from the null. After exclusion of these studies, the majority of studies still reported positive risk estimates. We therefore conclude that these new epidemiological studies directly support excess cancer risks from low-dose ionizing radiation. Furthermore, the magnitude of the cancer risks from these low-dose radiation exposures was statistically compatible with the radiation dose-related cancer risks of the atomic bomb survivors.
Collapse
Affiliation(s)
- Michael Hauptmann
- Correspondence to: Michael Hauptmann, Institute of Biostatistics and Registry Research, Brandenburg Medical School Theodor Fontane. Fehrbelliner Straße 38, 16816 Neuruppin, Germany (e-mail: )
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Daniels RD, Kendall GM, Thierry-Chef I, Linet MS, Cullings HM. Strengths and Weaknesses of Dosimetry Used in Studies of Low-Dose Radiation Exposure and Cancer. J Natl Cancer Inst Monogr 2020; 2020:114-132. [PMID: 32657346 PMCID: PMC7667397 DOI: 10.1093/jncimonographs/lgaa001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND A monograph systematically evaluating recent evidence on the dose-response relationship between low-dose ionizing radiation exposure and cancer risk required a critical appraisal of dosimetry methods in 26 potentially informative studies. METHODS The relevant literature included studies published in 2006-2017. Studies comprised case-control and cohort designs examining populations predominantly exposed to sparsely ionizing radiation, mostly from external sources, resulting in average doses of no more than 100 mGy. At least two dosimetrists reviewed each study and appraised the strengths and weaknesses of the dosimetry systems used, including assessment of sources and effects of dose estimation error. An overarching concern was whether dose error might cause the spurious appearance of a dose-response where none was present. RESULTS The review included 8 environmental, 4 medical, and 14 occupational studies that varied in properties relative to evaluation criteria. Treatment of dose estimation error also varied among studies, although few conducted a comprehensive evaluation. Six studies appeared to have known or suspected biases in dose estimates. The potential for these biases to cause a spurious dose-response association was constrained to three case-control studies that relied extensively on information gathered in interviews conducted after case ascertainment. CONCLUSIONS The potential for spurious dose-response associations from dose information appeared limited to case-control studies vulnerable to recall errors that may be differential by case status. Otherwise, risk estimates appeared reasonably free of a substantial bias from dose estimation error. Future studies would benefit from a comprehensive evaluation of dose estimation errors, including methods accounting for their potential effects on dose-response associations.
Collapse
Affiliation(s)
- Robert D Daniels
- Division of Science Integration, National Institute for Occupational Safety and Health, Cincinnati, OH
| | - Gerald M Kendall
- Cancer Epidemiology Unit, NDPH, University of Oxford, Oxford, UK
| | - Isabelle Thierry-Chef
- Barcelona Institute for Global Health, Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
- CIBER Epidemiología y Salud Pública, Madrid, Spain
| | - Martha S Linet
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Harry M Cullings
- Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan
| |
Collapse
|
9
|
Linet MS, Schubauer-Berigan MK, Berrington de González A. Outcome Assessment in Epidemiological Studies of Low-Dose Radiation Exposure and Cancer Risks: Sources, Level of Ascertainment, and Misclassification. J Natl Cancer Inst Monogr 2020; 2020:154-175. [PMID: 32657350 PMCID: PMC8454197 DOI: 10.1093/jncimonographs/lgaa007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 02/18/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Outcome assessment problems and errors that could lead to biased risk estimates in low-dose radiation epidemiological studies of cancer risks have not been systematically evaluated. METHODS Incidence or mortality risks for all cancers or all solid cancers combined and for leukemia were examined in 26 studies published in 2006-2017 involving low-dose (mean dose ≤100 mGy) radiation from environmental, medical, or occupational sources. We evaluated the impact of loss to follow-up, under- or overascertainment, outcome misclassification, and changing classifications occurring similarly or differentially across radiation dose levels. RESULTS Loss to follow-up was not reported in 62% of studies, but when reported it was generally small. Only one study critically evaluated the completeness of the sources of vital status. Underascertainment of cancers ("false negatives") was a potential shortcoming for cohorts that could not be linked with high-quality population-based registries, particularly during early years of exposure in five studies, in two lacking complete residential history, and in one with substantial emigration. False positives may have occurred as a result of cancer ascertainment from self- or next-of-kin report in three studies or from enhanced medical surveillance of exposed patients that could lead to detection bias (eg, reporting precancer lesions as physician-diagnosed cancer) in one study. Most pediatric but few adult leukemia studies used expert hematopathology review or current classifications. Only a few studies recoded solid cancers to the latest International Classification of Diseases or International Classification of Diseases for Oncology codes. These outcome assessment shortcomings were generally nondifferential in relation to radiation exposure level except possibly in four studies. CONCLUSION The majority of studies lacked information to enable comprehensive evaluation of all major sources of outcome assessment errors, although reported data suggested that the outcome assessment limitations generally had little effect on risk or biased estimates towards the null except possibly in four studies.
Collapse
Affiliation(s)
- Martha S Linet
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD
| | - Mary K Schubauer-Berigan
- Monographs Programme, Evidence Synthesis and Classification Section, International Agency for Research on Cancer, Lyon, France
| | - Amy Berrington de González
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Rockville, MD
| |
Collapse
|
10
|
Schubauer-Berigan MK, Berrington de Gonzalez A, Cardis E, Laurier D, Lubin JH, Hauptmann M, Richardson DB. Evaluation of Confounding and Selection Bias in Epidemiological Studies of Populations Exposed to Low-Dose, High-Energy Photon Radiation. J Natl Cancer Inst Monogr 2020; 2020:133-153. [PMID: 32657349 PMCID: PMC7355263 DOI: 10.1093/jncimonographs/lgaa008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Low-dose, penetrating photon radiation exposure is ubiquitous, yet our understanding of cancer risk at low doses and dose rates derives mainly from high-dose studies. Although a large number of low-dose cancer studies have been recently published, concern exists about the potential for confounding to distort findings. The aim of this study was to describe and assess the likely impact of confounding and selection bias within the context of a systematic review. METHODS We summarized confounding control methods for 26 studies published from 2006 to 2017 by exposure setting (environmental, medical, or occupational) and identified confounders of potential concern. We used information from these and related studies to assess evidence for confounding and selection bias. For factors in which direct or indirect evidence of confounding was lacking for certain studies, we used a theoretical adjustment to determine whether uncontrolled confounding was likely to have affected the results. RESULTS For medical studies of childhood cancers, confounding by indication (CBI) was the main concern. Lifestyle-related factors were of primary concern for environmental and medical studies of adult cancers and for occupational studies. For occupational studies, other workplace exposures and healthy worker survivor bias were additionally of interest. For most of these factors, however, review of the direct and indirect evidence suggested that confounding was minimal. One study showed evidence of selection bias, and three occupational studies did not adjust for lifestyle or healthy worker survivor bias correlates. Theoretical adjustment for three factors (smoking and asbestos in occupational studies and CBI in childhood cancer studies) demonstrated that these were unlikely to explain positive study findings due to the rarity of exposure (eg, CBI) or the relatively weak association with the outcome (eg, smoking or asbestos and all cancers). CONCLUSION Confounding and selection bias are unlikely to explain the findings from most low-dose radiation epidemiology studies.
Collapse
Affiliation(s)
- Mary K Schubauer-Berigan
- Evidence Synthesis and Classification Section, International Agency for Research on Cancer, Lyon, France
| | | | - Elisabeth Cardis
- Radiation Programme, Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Dominique Laurier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
| | - Jay H Lubin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Michael Hauptmann
- Division of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, The Netherlands (MH); Brandenburg Medical School, Institute of Biostatistics and Registry Research, Neuruppin, Germany
| | - David B Richardson
- Department of Epidemiology, University of North Carolina, School of Public Health, Chapel Hill, NC, USA
| |
Collapse
|
11
|
Gilbert ES, Little MP, Preston DL, Stram DO. Issues in Interpreting Epidemiologic Studies of Populations Exposed to Low-Dose, High-Energy Photon Radiation. J Natl Cancer Inst Monogr 2020; 2020:176-187. [PMID: 32657345 PMCID: PMC7355296 DOI: 10.1093/jncimonographs/lgaa004] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/02/2020] [Indexed: 01/19/2023] Open
Abstract
This article addresses issues relevant to interpreting findings from 26 epidemiologic studies of persons exposed to low-dose radiation. We review the extensive data from both epidemiologic studies of persons exposed at moderate or high doses and from radiobiology that together have firmly established radiation as carcinogenic. We then discuss the use of the linear relative risk model that has been used to describe data from both low- and moderate- or high-dose studies. We consider the effects of dose measurement errors; these can reduce statistical power and lead to underestimation of risks but are very unlikely to bring about a spurious dose response. We estimate statistical power for the low-dose studies under the assumption that true risks of radiation-related cancers are those expected from studies of Japanese atomic bomb survivors. Finally, we discuss the interpretation of confidence intervals and statistical tests and the applicability of the Bradford Hill principles for a causal relationship.
Collapse
Affiliation(s)
- Ethel S Gilbert
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
| | - Mark P Little
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
| | | | - Daniel O Stram
- Department of Preventive Medicine, School of Medicine, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
12
|
Berrington de Gonzalez A, Daniels RD, Cardis E, Cullings HM, Gilbert E, Hauptmann M, Kendall G, Laurier D, Linet MS, Little MP, Lubin JH, Preston DL, Richardson DB, Stram D, Thierry-Chef I, Schubauer-Berigan MK. Epidemiological Studies of Low-Dose Ionizing Radiation and Cancer: Rationale and Framework for the Monograph and Overview of Eligible Studies. J Natl Cancer Inst Monogr 2020; 2020:97-113. [PMID: 32657348 PMCID: PMC7610154 DOI: 10.1093/jncimonographs/lgaa009] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/13/2020] [Indexed: 12/21/2022] Open
Abstract
Whether low-dose ionizing radiation can cause cancer is a critical and long-debated question in radiation protection. Since the Biological Effects of Ionizing Radiation report by the National Academies in 2006, new publications from large, well-powered epidemiological studies of low doses have reported positive dose-response relationships. It has been suggested, however, that biases could explain these findings. We conducted a systematic review of epidemiological studies with mean doses less than 100 mGy published 2006-2017. We required individualized doses and dose-response estimates with confidence intervals. We identified 26 eligible studies (eight environmental, four medical, and 14 occupational), including 91 000 solid cancers and 13 000 leukemias. Mean doses ranged from 0.1 to 82 mGy. The excess relative risk at 100 mGy was positive for 16 of 22 solid cancer studies and 17 of 20 leukemia studies. The aim of this monograph was to systematically review the potential biases in these studies (including dose uncertainty, confounding, and outcome misclassification) and to assess whether the subset of minimally biased studies provides evidence for cancer risks from low-dose radiation. Here, we describe the framework for the systematic bias review and provide an overview of the eligible studies.
Collapse
Affiliation(s)
| | - Robert D Daniels
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Elisabeth Cardis
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | - Ethel Gilbert
- Division of Cancer Epidemiology & Genetics, Radiation Epidemiology Branch, Bethesda, MD, USA
| | - Michael Hauptmann
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
- Brandenburg Medical School Theodor Fontane, Institute of Biostatistics and Registry Research, Neuruppin, Germany
| | | | | | - Martha S Linet
- Division of Cancer Epidemiology & Genetics, Radiation Epidemiology Branch, Bethesda, MD, USA
| | - Mark P Little
- Division of Cancer Epidemiology & Genetics, Radiation Epidemiology Branch, Bethesda, MD, USA
| | - Jay H Lubin
- Division of Cancer Epidemiology & Genetics, Radiation Epidemiology Branch, Bethesda, MD, USA
| | | | | | - Daniel Stram
- University of Southern California, Los Angeles, CA
| | - Isabelle Thierry-Chef
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Catalonia, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | |
Collapse
|
13
|
A Cohort Study of Korean Radiation Workers: Baseline Characteristics of Participants. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17072328. [PMID: 32235620 PMCID: PMC7177891 DOI: 10.3390/ijerph17072328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/22/2022]
Abstract
The Korean Radiation Worker Study investigated the health effects of protracted low-dose radiation among nuclear-related occupations in the Nuclear Safety and Security Commission in Korea. From 2016–2017, 20,608 workers were enrolled (86.5% men and 30.7% nuclear power plant workers). The mean cumulative dose ± standard deviation between 1984 and 2017 (1st quarter) was 11.8 ± 28.8 (range 0–417) mSv. Doses below recording level (≤0.1 mSv) were reported in 7901 (38.3%) cases; 431 (2%) had cumulative doses ≥100 mSv. From 1999–2016, 212 cancers (189 men, 23 women) occurred; thyroid cancer predominated (39.2%, 72 men, 11 women). In men, the standardized incidence ratio (SIR) for all cancers was significantly decreased (SIR = 0.76, 95% CI 0.66–0.88); however, that for thyroid cancer was significantly increased (SIR = 1.94, 95% CI 1.54–2.44). Compared to the non-exposed group (≤0.1 mSv), the relative risk (RR) in the exposed group (>0.1 mSv) after adjusting for sex, attained age, smoking status, and duration of employment was 0.82 (95% CI 0.60–1.12) for all cancers and 0.83 (95% CI 0.49–1.83) for thyroid cancer. The preliminary findings from this baseline study with a shorter follow-up than the latency period for solid cancer cannot exclude possible associations between radiation doses and cancer risk.
Collapse
|
14
|
Sadeghi H, Rafei M, Bahrami M, Haghdoost A, Shabani Y. Attributable risk fraction of four lifestyle risk factors of thyroid cancer: a meta-analysis. J Public Health (Oxf) 2019; 40:e91-e98. [PMID: 28977647 DOI: 10.1093/pubmed/fdx088] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 07/18/2017] [Indexed: 11/13/2022] Open
Abstract
Background Lifestyle risk factors such as obesity, overweight, smoking and radiation exposure related to thyroid cancer. This study estimated the amount of excess risk that attributed to risk factors. Methods Major electronic databases were searched until February 2016. Epidemiological studies addressing the association between lifestyle risk factors and thyroid cancer were enrolled. The results were expressed as ARF with 95% confidence intervals (CIs) using a random-effects-model. Results We identified a total of 13 321 references and included 17 studies. The excess risk of thyroid cancer attributable to radiation exposure was 14% (95% CI: 5%, 23%; eight studies, I2 = 88.7%), to obesity was 13% (95% CI: 5%, 21%; four studies, I2 = 68.7%), to overweight was 10% (95% CI: 2%, 17%; four studies, I2 = 4.1%) and to smoking was -13% (95% CI: -33%, 6%; five studies, I2 = 30.6%). So obesity, overweight and radiation exposure are significantly associated with increased thyroid cancer risk and smoking has a protective effect on thyroid cancer but not significant. Conclusion A significant amount of the incidence of thyroid cancer is attributable to lifestyle risk factors. Since these factors are entirely preventable, so it is necessary to reduce factors that are associated with increased thyroid cancer risk and proper education to the community. Thus weight loss and protection against radiation can effectively reduce the incidence rate of thyroid cancer but smoking can have a protective effect.
Collapse
Affiliation(s)
- Hajar Sadeghi
- Faculty of Khomein University of Medical Sciences, Khomein, Iran
| | | | | | - AliAkbar Haghdoost
- Community Medicine Department and Physiology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Yazdan Shabani
- Member of Student Research Committee of Arak University of Medical Sciences, Arak, Iran
| |
Collapse
|
15
|
Seo S, Lim WY, Lee DN, Kim JU, Cha ES, Bang YJ, Lee WJ, Park S, Jin YW. Assessing the health effects associated with occupational radiation exposure in Korean radiation workers: protocol for a prospective cohort study. BMJ Open 2018; 8:e017359. [PMID: 29602835 PMCID: PMC5884371 DOI: 10.1136/bmjopen-2017-017359] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION The cancer risk of radiation exposure in the moderate-to-high dose range has been well established. However, the risk remains unclear at low-dose ranges with protracted low-dose rate exposure, which is typical of occupational exposure. Several epidemiological studies of Korean radiation workers have been conducted, but the data were analysed retrospectively in most cases. Moreover, groups with relatively high exposure, such as industrial radiographers, have been neglected. Therefore, we have launched a prospective cohort study of all Korean radiation workers to assess the health effects associated with occupational radiation exposure. METHODS AND ANALYSIS Approximately 42 000 Korean radiation workers registered with the Nuclear Safety and Security Commission from 2016 to 2017 are the initial target population of this study. Cohort participants are to be enrolled through a nationwide self-administered questionnaire survey between 24 May 2016 and 30 June 2017. As of 31 March 2017, 22 982 workers are enrolled in the study corresponding to a response rate of 75%. This enrolment will be continued at 5-year intervals to update information on existing study participants and recruit newly hired workers. Survey data will be linked with the national dose registry, the national cancer registry, the national vital statistics registry and national health insurance data via personal identification numbers. Age-specific and sex-specific standardised incidence and mortality ratios will be calculated for overall comparisons of cancer risk. For dose-response assessment, excess relative risk (per Gy) and excess absolute risk (per Gy) will be estimated with adjustments for birth year and potential confounders, such as lifestyle factors and socioeconomic status. ETHICS AND DISSEMINATION This study has received ethical approval from the institutional review board of the Korea Institute of Radiological and Medical Sciences (IRB No. K-1603-002-034). All participants provided written informed consent prior to enrolment. The findings of the study will be disseminated through scientific peer-reviewed journals and be provided to the public, including radiation workers, via the study website (http://www.rhs.kr/) and onsite radiation safety education.
Collapse
Affiliation(s)
- Songwon Seo
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| | - Wan Young Lim
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| | - Dal Nim Lee
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| | - Jung Un Kim
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| | - Eun Shil Cha
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Ye Jin Bang
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Won Jin Lee
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Sunhoo Park
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| | - Young Woo Jin
- Laboratory of Low Dose Risk Assessment, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Korea
| |
Collapse
|
16
|
Qu SG, Gao J, Tang B, Yu B, Shen YP, Tu Y. Low-dose ionizing radiation increases the mortality risk of solid cancers in nuclear industry workers: A meta-analysis. Mol Clin Oncol 2018; 8:703-711. [PMID: 29725540 DOI: 10.3892/mco.2018.1590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/28/2018] [Indexed: 11/05/2022] Open
Abstract
Low-dose ionizing radiation (LDIR) may increase the mortality of solid cancers in nuclear industry workers, but only few individual cohort studies exist, and the available reports have low statistical power. The aim of the present study was to focus on solid cancer mortality risk from LDIR in the nuclear industry using standard mortality ratios (SMRs) and 95% confidence intervals. A systematic literature search through the PubMed and Embase databases identified 27 studies relevant to this meta-analysis. There was statistical significance for total, solid and lung cancers, with meta-SMR values of 0.88, 0.80, and 0.89, respectively. There was evidence of stochastic effects by IR, but more definitive conclusions require additional analyses using standardized protocols to determine whether LDIR increases the risk of solid cancer-related mortality.
Collapse
Affiliation(s)
- Shu-Gen Qu
- Department of Radiation Health, Research Center of Radiation Protection and Nuclear Safety, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Jin Gao
- Department of Radiation Health, Research Center of Radiation Protection and Nuclear Safety, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Bo Tang
- Department of Radiation Health, Research Center of Radiation Protection and Nuclear Safety, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Bo Yu
- Department of Radiation Health, Research Center of Radiation Protection and Nuclear Safety, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Yue-Ping Shen
- Department of Health Statistics, School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Yu Tu
- Department of Radiation Health, Research Center of Radiation Protection and Nuclear Safety, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| |
Collapse
|
17
|
Affiliation(s)
- David G. Hoel
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| |
Collapse
|
18
|
Seo S, Lee D, Seong KM, Park S, Kim SG, Won JU, Jin YW. Radiation-related occupational cancer and its recognition criteria in South Korea. Ann Occup Environ Med 2018; 30:9. [PMID: 29435340 PMCID: PMC5797363 DOI: 10.1186/s40557-018-0219-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 01/17/2018] [Indexed: 12/15/2022] Open
Abstract
Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker’s cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.
Collapse
Affiliation(s)
- Songwon Seo
- 1National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812 Republic of Korea.,2Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Dalnim Lee
- 1National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812 Republic of Korea
| | - Ki Moon Seong
- 1National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812 Republic of Korea
| | - Sunhoo Park
- 1National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812 Republic of Korea
| | - Soo-Geun Kim
- 3Department of Occupational Medicine, Sungkyunkwan University, School of Medicine, Seoul, Korea
| | - Jong-Uk Won
- 4The Institute for Occupational Health, Yonsei University College of Medicine, Seoul, Korea
| | - Young Woo Jin
- 1National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, 75, Nowon-ro, Nowon-gu, Seoul, 01812 Republic of Korea
| |
Collapse
|
19
|
Seong KM, Seo S, Lee D, Kim MJ, Lee SS, Park S, Jin YW. Is the Linear No-Threshold Dose-Response Paradigm Still Necessary for the Assessment of Health Effects of Low Dose Radiation? J Korean Med Sci 2016; 31 Suppl 1:S10-23. [PMID: 26908982 PMCID: PMC4756336 DOI: 10.3346/jkms.2016.31.s1.s10] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/17/2015] [Indexed: 12/17/2022] Open
Abstract
Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.
Collapse
Affiliation(s)
- Ki Moon Seong
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Songwon Seo
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Dalnim Lee
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Min-Jeong Kim
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Seung-Sook Lee
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Sunhoo Park
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| | - Young Woo Jin
- Laboratory of Radiation Exposure & Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological & Medical Sciences, Seoul, Korea
| |
Collapse
|
20
|
Yoon JH, Ahn YS. A large, nationwide, longitudinal study of central nervous system diseases among Korean workers exposed to manganese. Parkinsonism Relat Disord 2015; 21:194-8. [DOI: 10.1016/j.parkreldis.2014.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 10/09/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
|
21
|
Affiliation(s)
- Jae Hoon Chung
- Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| |
Collapse
|
22
|
Abstract
Leukemia is a complex disease, which only became better understood during the last decades following the development of new laboratory techniques and diagnostic methods. Despite our improved understanding of the physiology of the disease, little is yet known about the causes of leukemia. A variety of potential risk factors have been suggested so far, including personal habits and lifestyle, and a wide range of occupational or environmental exposures. A causal association with leukemia has only been documented to date for ionizing radiation, benzene and treatment with cytostatic drugs, but there is an ongoing scientific debate on the possible association of leukemia with a number of other work-related hazards. In this article, we have reviewed scientific studies, published over the past 5 years, which investigated potential associations between leukemia and exposure to occupational risk factors. The systematic literature review took place via electronic databases, using specific search criteria, and independent reviewers have further filtered the search results to identify the number of articles, presented in our paper. A large number of studies included in the review referred to the effects of ionizing radiation, where new data suggest that the effects of exposure to small doses of ionizing radiation should probably be reevaluated. Some other works appear to substantiate a potential association of the disease with certain pesticides. Further research is also suggested regarding the role of infectious agents or exposure to certain chemicals like formaldehyde or butadiene in the pathogenesis of leukemia.
Collapse
|
23
|
Daniels RD, Schubauer-Berigan MK. A meta-analysis of leukaemia risk from protracted exposure to low-dose gamma radiation. Occup Environ Med 2011; 68:457-64. [PMID: 20935290 PMCID: PMC3095477 DOI: 10.1136/oem.2009.054684] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2010] [Indexed: 01/18/2023]
Abstract
CONTEXT More than 400,000 workers annually receive a measurable radiation dose and may be at increased risk of radiation-induced leukaemia. It is unclear whether leukaemia risk is elevated with protracted, low-dose exposure. OBJECTIVE We conducted a meta-analysis examining the relationship between protracted low-dose ionising radiation exposure and leukaemia. DATA SOURCES Reviews by the National Academies and United Nations provided a summary of informative studies published before 2005. PubMed and Embase databases were searched for additional occupational and environmental studies published between 2005 and 2009. STUDY SELECTION We selected 23 studies that: (1) examined the association between protracted exposures to ionising radiation and leukaemia excluding chronic lymphocytic subtype; (2) were a cohort or nested case-control design without major bias; (3) reported quantitative estimates of exposure; and (4) conducted exposure-response analyses using relative or excess RR per unit exposure. METHODS Studies were further screened to reduce information overlap. Random effects models were developed to summarise between-study variance and obtain an aggregate estimate of the excess RR at 100 mGy. Publication bias was assessed by trim and fill and Rosenthal's file drawer methods. RESULTS We found an ERR at 100 mGy of 0.19 (95% CI 0.07 to 0.32) by modelling results from 10 studies and adjusting for publication bias. Between-study variance was not evident (p=0.99). CONCLUSIONS Protracted exposure to low-dose gamma radiation is significantly associated with leukaemia. Our estimate agreed well with the leukaemia risk observed among exposed adults in the Life Span Study (LSS) of atomic bomb survivors, providing increased confidence in the current understanding of leukaemia risk from ionising radiation. However, unlike the estimates obtained from the LSS, our model provides a precise, quantitative summary of the direct estimates of excess risk from studies of protracted radiation exposures.
Collapse
Affiliation(s)
- R D Daniels
- Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, US Centers for Disease Control and Prevention, 4676 Columbia Pkwy, R-14, Cincinnati, OH 45226, USA.
| | | |
Collapse
|
24
|
Risk factors for breast cancer, including occupational exposures. Saf Health Work 2011; 2:1-8. [PMID: 22953181 PMCID: PMC3431884 DOI: 10.5491/shaw.2011.2.1.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 02/20/2011] [Indexed: 11/30/2022] Open
Abstract
The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr). For breast cancer the following substances have been classified as "carcinogenic to humans" (Group 1): alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure). Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification "probably carcinogenic to humans" (Group 2A) includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women.
Collapse
|
25
|
Kim EA, Lee WJ, Son M, Kang SK. Occupational lymphohematopoietic cancer in Korea. J Korean Med Sci 2010; 25:S99-104. [PMID: 21258598 PMCID: PMC3023362 DOI: 10.3346/jkms.2010.25.s.s99] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 06/07/2010] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to review the existing studies on lymphohematopoietic (LHP) cancer in Korea, estimate the prevalence of workers exposed to carcinogens, and determine the population attributable fraction (PAF) of leukemia. Two case series and 4 case reports were reviewed. Using official statistics, the prevalence of benzene exposure and ionizing radiation exposure was estimated. Based on the prevalence of exposure and the relative risk, The PAF of leukemia was calculated. Between 1996 and 2005, 51 cases of LHP cancer were reported from the compensation system. Greater than 50% of occupational LHP cancer was leukemia, and the most important cause was benzene. In a cohort study, the standardized incidence ratio was 2.71 (95% CI, 0.56-7.91). The prevalence of exposure was 2.5% and 2.2% in 1995 and 2000, respectively. Using the 1995 prevalence, 3.6-4.8% and 0.1% of cases with leukemia were attributable to benzene and ionizing radiation exposure, respectively, which resulted in 39.7-51.4 cases per year. Benzene is the most important cause of occupational leukemia in Korea. Considering the estimated PAF in this study, the annual number of occupational LHP cancer (51 cases during 10-yr period), might be underreported within the compensation system.
Collapse
Affiliation(s)
- Eun-A Kim
- Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, Incheon, Korea
| | - Won Jin Lee
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Mia Son
- Department of Preventive Medicine, College of Medicine, Kangwon National University, Chuncheon, Korea
| | - Seong-Kyu Kang
- Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, Incheon, Korea
| |
Collapse
|
26
|
Jin YW, Jeong M, Moon K, Jo MH, Kang SK. Ionizing radiation-induced diseases in Korea. J Korean Med Sci 2010; 25:S70-6. [PMID: 21258594 PMCID: PMC3023356 DOI: 10.3346/jkms.2010.25.s.s70] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 09/08/2010] [Indexed: 11/25/2022] Open
Abstract
Radiation risk has become well known through epidemiological studies of clinically or occupationally exposed populations, animal experiments, and in vitro studies; however, the study of radiation related or induced disease has been limited in Korea. This study is to find the level of occupational radiation exposure for various kinds of accidents, compensated occupational diseases, related studies, and estimations on future occupational disease risks. Research data of related institutions were additionally investigated. About 67% of 62,553 radiation workers had no exposure or less than 1.2 mSv per year. The 5 reported cases on radiation accident patients in Korea occurred during nondestructive testing. According to the recent rapid increase in the number of workers exposed to radiation, a higher social recognition of cancer, and an increasing cancer mortality rate, it is expected that occupational disease compensation will rapidly increase as well. Therefore, it is important to develop scientific and objective decision methods, such as probability of causation and screening dose in the establishment of an exposure and health surveillance system.
Collapse
Affiliation(s)
- Young-Woo Jin
- Division of Radiation Effect Research, Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., LTD, Seoul, Korea
| | - Meeseon Jeong
- Division of Radiation Effect Research, Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., LTD, Seoul, Korea
| | - Kieun Moon
- Division of Radiation Effect Research, Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., LTD, Seoul, Korea
| | - Min-Heui Jo
- Occupational Safety and Health Research Institute, Korea Safety and Health Agency, Incheon, Korea
| | - Seong-Kyu Kang
- Occupational Safety and Health Research Institute, Korea Safety and Health Agency, Incheon, Korea
| |
Collapse
|
27
|
Abstract
Malignant mesothelioma and lung cancer are representative examples of occupational cancer. Lung cancer is the leading cause of cancer death, and the incidence of malignant mesothelioma is expected to increase sharply in the near future. Although information about lung carcinogen exposure is limited, it is estimated that the number of workers exposed to carcinogens has declined. The first official case of occupational cancer was malignant mesothelioma caused by asbestos exposure in the asbestos textile industry in 1992. Since then, compensation for occupational respiratory cancer has increased. The majority of compensated lung cancer was due to underlying pneumoconiosis. Other main causative agents of occupational lung cancer included asbestos, hexavalent chromium, and crystalline silica. Related jobs included welders, foundry workers, platers, plumbers, and vehicle maintenance workers. Compensated malignant mesotheliomas were associated with asbestos exposure. Epidemiologic studies conducted in Korea have indicated an elevated risk of lung cancer in pneumoconiosis patients, foundry workers, and asbestos textile workers. Occupational respiratory cancer has increased during the last 10 to 20 yr though carcinogen-exposed population has declined in the same period. More efforts to advance the systems for the investigation, prevention and management of occupational respiratory cancer are needed.
Collapse
Affiliation(s)
- Hye-Eun Lee
- Occupational Safety and Health Research Institute, KOSHA, Inchoen, Korea
- Department of Environmental Health, School of Public Health, Seoul National University, Seoul, Korea
| | - Hyoung Ryoul Kim
- Department of Preventive Medicine and Industrial Medical Center, The Catholic University of Korea, College of Medicine, Seoul, Korea
| |
Collapse
|
28
|
Abstract
Objectives The extent of the occupational cancer burden has rarely been estimated in Korea. The aim of this study is to provide an estimation of the population attributable fraction (PAF) of occupational cancer in Korea. Methods Nine kinds of Group 1 carcinogens addressed by the International Agency for Research on Cancer (IARC) and 7 kinds of cancer were selected for the target carcinogens and diseases, respectively. The prevalence of carcinogen-exposed workers was estimated and correction factors were applied so that the value would be representative of the total population. Data on relative risk (RR) were taken from IARC reports and were compared with the RRs from the studies on Korean workers. The PAF was estimated according to Levin's formula. Results The proportion of the general Korean population exposed to carcinogens was 9.7%. The PAF of total cancer was 1.1% for incident cancer cases and 1.7% for cancer deaths. The PAFs of lung cancer and leukemia were 7.0% and 4.%, respectively. With the RRs reported from Korean studies, the PAF for lung cancer and leukemia were 3.7% and 3.4%, respectively. Conclusion The PAF in this study (1.1%) was lower than that reported in previous studies (2-4%) from developed countries. Considering that only 9 of the 29 kinds of Group 1 carcinogens were included in this study, the PAF might be underestimated. However, because the process of industrialization in Korea differs from that which occurred in other developed countries, 1.1% of the PAF might be appropriate for Korea.
Collapse
|
29
|
Park ES, Moon K, Kim HN, Lee WJ, Jin YW. [Radiation exposure and cancer mortality among nuclear power plant workers: a meta-analysis]. J Prev Med Public Health 2010; 43:185-92. [PMID: 20383052 DOI: 10.3961/jpmph.2010.43.2.185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES We conducted a meta-analysis to investigate the relationship between low external doses of ionizing radiation exposure and the risk of cancer mortality among nuclear power plant workers. METHODS We searched MEDLINE using key words related to low dose and cancer risk. The selected articles were restricted to those written in English from 1990 to January 2009. We excluded those studies with no fit to the selection criteria and we included the cited references in published articles to minimize publication bias. Through this process, a total of 11 epidemiologic studies were finally included. RESULTS We found significant decreased deaths from all cancers (SMR = 0.75, 95% CI = 0.62 - 0.90), all cancers excluding leukemia, solid cancer, mouth and pharynx, esophagus, stomach, rectum, liver and gallbladder, pancreas, lung, prostate, lymphopoietic and hematopoitic cancer. The findings of this meta-analysis were similar with those of the 15 Country Collaborative Study conducted by the International Agency for Research on Cancer. A publication bias was found only for liver and gallbladder cancer (p = 0.015). Heterogeneity was observed for all cancers, all cancers excluding leukemia, solid cancer, esophagus, colon and lung cancer. CONCLUSIONS Our findings of low mortality for stomach, rectum, liver and gallbladder cancers may explained by the health worker effect. Yet further studies are needed to clarify the low SMR of cancers, for which there is no useful screening tool, in nuclear power plant workers.
Collapse
Affiliation(s)
- Eun Sook Park
- Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., Ltd., Korea
| | | | | | | | | |
Collapse
|
30
|
Jeong M, Jin YW, Yang KH, Ahn YO, Cha CY. Radiation exposure and cancer incidence in a cohort of nuclear power industry workers in the Republic of Korea, 1992-2005. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2010; 49:47-55. [PMID: 19823862 DOI: 10.1007/s00411-009-0247-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 09/26/2009] [Indexed: 05/14/2023]
Abstract
This study examines for the first time cancer incidence between radiation and non-radiation workers in nuclear power facilities in the Republic of Korea. Radiation workers were defined as persons who were issued with a dosimeter at nuclear power facilities, until 2005. All analyses were conducted on male workers only (in total 16,236 individuals) because of the sparseness of females. Statistical analyses were carried out using the standardized incidence ratio (SIR), to compare the cancer risks of radiation and non-radiation workers with those of the general population, and the chi(2) trend test was used to investigate any increase in cancer rates with dose. Poisson regression was also used to estimate the rate ratio (RR) and the excess relative risk (ERR) after considering the confounding effect due to smoking. During 1992-2005, 99 cancer cases in 63,503 person-years were observed among 8,429 radiation workers, while 104 cancer cases were observed in 48,301 person-years among 7,807 non-radiation workers. When compared with the site- and age-specific cancer rates for the male population of Korea, the SIR for all cancers combined was 1.07 [95% confidence interval (CI) 0.87-1.30] for radiation workers, and 0.88 (95% CI 0.72-1.06) for non-radiation workers, respectively. The RR for radiation workers compared with non-radiation workers was 1.18 (95% CI 0.89-1.58) for all cancers combined. The SIRs for thyroid cancer were noticeably high for both radiation and non-radiation workers, possibly due to the screening effect, but analysis of the RR showed that there was no statistically significant difference in thyroid cancer incidence rates between the two groups. For lung cancer, radiation workers showed a higher incidence rate as compared to non-radiation workers, with the RR being 3.48 (95% CI 1.19-11.48). A chi(2) trend test showed that there was no evidence for an increase in cancer rate with increasing cumulative dose for all cancers combined (p = 0.5108). The ERR per Sievert was estimated to be 1.69 (95% CI -2.07 to 8.21) for all cancers combined assuming a 10 years lag time. Consequently, a significant excess of cancer incidence among radiation workers in the nuclear power industry in Korea was not observed. Further follow-up and an expansion of the cohort are needed to overcome the lack of statistical power in the study.
Collapse
Affiliation(s)
- Meeseon Jeong
- Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., Ltd., 388-1 Ssangmoon-Dong, Dobong-Gu, Seoul, 132-703, Korea
| | | | | | | | | |
Collapse
|
31
|
Relationship between occupational exposure to ionizing radiation and mortality at the French electricity company, period 1961-2003. Int Arch Occup Environ Health 2010; 83:935-44. [PMID: 20148259 DOI: 10.1007/s00420-010-0509-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 01/14/2010] [Indexed: 12/23/2022]
Abstract
PURPOSE Epidemiological studies in nuclear industry workers can produce relevant information to better appreciate the health risks related to chronic external exposure to low doses of ionizing radiation (IR). This work examined the relations between exposure to IR and mortality in workers at the French Electricity Company (EDF), followed up to year 2003. METHODS Permanent staff who had worked for at least 1 year at EDF during period 1961-1994 and who had been monitored for exposure to IR were included (n = 22,393). One-sided trend tests for mortality according to cumulative dose and relative risks at 100 mSv were estimated using Poisson regression. Main analyses were stratified on age, sex, calendar time and education. RESULTS A total of 874 deaths occurred, and 66 workers were lost to follow-up. Median age at end of follow-up was 48. None of the causes of death investigated increased significantly according to dose, except cerebrovascular diseases (p = 0.01), but this last observation was based on only 22 cases. CONCLUSIONS These results do not allow dismissing a possible influence of IR on cancer risk in this population. The cohort is still relatively young and therefore confidence intervals for estimated relative risks remain wide, although they have considerably narrowed since a previous analysis. Chance is a possible explanation for the association between IR and cerebrovascular mortality, due to the low number of cases on which it is based. These results thus need to be stabilized by conducting joint analyses with similar cohorts.
Collapse
|