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Iavicoli I, Fontana L, Santocono C, Guarino D, Laudiero M, Calabrese EJ. The challenges of defining hormesis in epidemiological studies: The case of radiation hormesis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166030. [PMID: 37544458 DOI: 10.1016/j.scitotenv.2023.166030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/08/2023]
Abstract
In the current radiation protection system, preventive measures and occupational exposure limits for controlling occupational exposure to ionizing radiation are based on the linear no-threshold extrapolation model. However, currently an increasing body of evidence indicates that this paradigm predicts very poorly biological responses in the low-dose exposure region. In addition, several in vitro and in vivo studies demonstrated the presence of hormetic dose response curves correlated to ionizing radiation low exposure. In this regard, it is noteworthy that also the findings of different epidemiological studies, conducted in different categories of occupationally exposed workers (e.g., healthcare, nuclear industrial and aircrew workers), observed lower rates of mortality and/or morbidity from cancer and/or other diseases in exposed workers than in unexposed ones or in the general population, then suggesting the possible occurrence of hormesis. Nevertheless, these results should be considered with caution since the identification of hormetic response in epidemiological studies is rather challenging because of a number of major limitations. In this regard, some of the most remarkable shortcomings found in epidemiological studies performed in workers exposed to ionizing radiation are represented by lack or inadequate definition of exposure doses, use of surrogates of exposure, narrow dose ranges, lack of proper control groups and poor evaluation of confounding factors. Therefore, considering the valuable role and contribution that epidemiological studies might provide to the complex risk assessment and management process, there is a clear and urgent need to overcome the aforementioned limits in order to achieve an adequate, useful and more real-life risk assessment that should also include the key concept of hormesis. Thus, in the present conceptual article we also discuss and provide possible approaches to improve the capacity of epidemiological studies to identify/define the hormetic response and consequently improve the complex process of risk assessment of ionizing radiation at low exposure doses.
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Affiliation(s)
- Ivo Iavicoli
- Department of Public Health, Section of Occupational Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
| | - Luca Fontana
- Department of Public Health, Section of Occupational Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy
| | - Carolina Santocono
- Department of Public Health, Section of Occupational Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy
| | - Davide Guarino
- Department of Public Health, Section of Occupational Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy
| | - Martina Laudiero
- Department of Public Health, Section of Occupational Medicine, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA
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Russo AC, Marqueze EC, Furst MSG, Benevides EADSE, Roscani RC, Salim CA, Guimarães PCV. Aircrew Health: A Systematic Review of Physical Agents as Occupational Risk Factors. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:ijerph20105849. [PMID: 37239575 DOI: 10.3390/ijerph20105849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/20/2023] [Accepted: 04/06/2023] [Indexed: 05/28/2023]
Abstract
The primary objective of this systematic review was to analyze the main physical agents representing risk factors for commercial aircrew, together with their consequences. The secondary objective was to identify the countries in which studies on the topic were conducted, as well as the quality of the publications available. Thirty-five articles, published between 1996 and 2020, were selected for the review, having met all inclusion criteria. The majority of studies were conducted in the United States, Germany, and Finland and had moderate or low methodological quality of evidence. The main risk factors for aircrew identified in publications were exposure to abnormal air pressure, cosmic radiation, noise, and vibrations. Hypobaric pressure was explored in response to demands for studies on this agent, a factor which may lead to otic and ear barotraumas, as well as acceleration of atherosclerosis of the carotid artery. However, there is a dearth of research exploring this phenomenon.
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Affiliation(s)
- Ana Carolina Russo
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
| | - Elaine Cristina Marqueze
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
| | - Mariana Souza Gomes Furst
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
| | | | - Rodrigo Caoduro Roscani
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
| | - Celso Amorim Salim
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
| | - Paulo Cesar Vaz Guimarães
- Fundação Jorge Duprat Figueiredo de Segurança e Medicina do Trabalho-Fundacentro, São Paulo 30180-100, Brazil
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Aragón-Vela J, Bejder J, R Huertas J, Plaza-Diaz J, Nordsborg NB. Does intermittent exposure to high altitude increase the risk of cardiovascular disease in workers? A systematic narrative review. BMJ Open 2020; 10:e041532. [PMID: 33444211 PMCID: PMC7682469 DOI: 10.1136/bmjopen-2020-041532] [Citation(s) in RCA: 2] [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] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Several working groups (eg, miners, flight crews and soldiers) are subjected to chronic intermittent hypoxic exposure. The cardiovascular implications have been studied but not systematically reviewed with focus on possible negative health implications. The aim of the present review was to systematically evaluate the hypothesis that intermittent hypoxic exposure causes cardiovascular stress detrimental to health in workers. DESIGN Systematic review. DATA SOURCES Electronic database search of PubMed, Scopus and Web of Science up to April 2020. ELIGIBILITY CRITERIA Studies of workers ≥18 years repeatedly subjected to months to years of irregular intermittent hypoxia, lasting from a few hours (eg, flight crews), one or a few days (eg, soldiers), or several days to weeks (eg, miners working at high altitude), written in English and evaluating the effect of intermittent hypoxia on cardiovascular disease were included. Animal studies, books, book chapters, personal communication and abstracts were excluded. The primary outcome measure was changes in standardised mortality ratio. DATA EXTRACTION AND SYNTHESIS Two independent reviewers extracted data and assessed risk of bias using the Cochrane Collaboration's tool. RESULTS 119 articles were identified initially, 31 of which met the inclusion criteria. Of these, 17 were retrospective cohort mortality studies (irregular short-term intermittent hypoxia), and 14 studies were observational (long-term intermittent hypoxia). The population of irregular short-term intermittent hypoxia users (flight crew) showed a lower mortality by cardiovascular disease. Long-term intermittent hypoxia over several years such as in miners or soldiers may produce increased levels of cardiac disorders (12 studies), though this is probably confounded by factors such as obesity and socioeconomic status. CONCLUSION This systematic narrative review found that cardiovascular disease mortality in flight crews is lower than average, whereas miners and soldiers exposed to intermittent hypoxia experience increased risks of cardiovascular diseases. The impact of socioeconomic status and lifestyle appears of importance. PROSPERO REGISTRY NUMBER CRD42020171301.
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Affiliation(s)
- Jerónimo Aragón-Vela
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jesús R Huertas
- Department of Physiology, School of Sport Sciences, University of Granada, Granada, Spain
- Institute of Nutrition and Food Technology "José Mataix", Biomedical Research Centre, University of Granada, Granada, Spain
| | - Julio Plaza-Diaz
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry & MolecularBiology II, School of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria IBS Granada, Complejo Hospitalario Universitario de Granada, Granada, Spain
| | - Nikolai B Nordsborg
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
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Dreger S, Wollschläger D, Schafft T, Hammer GP, Blettner M, Zeeb H. Cohort study of occupational cosmic radiation dose and cancer mortality in German aircrew, 1960–2014. Occup Environ Med 2020; 77:285-291. [DOI: 10.1136/oemed-2019-106165] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/12/2019] [Accepted: 01/13/2020] [Indexed: 11/03/2022]
Abstract
ObjectivesTo determine cancer mortality compared with the general population and to examine dose-response relationships between cumulative occupational radiation dose and specific cancer outcomes in the German aircrew cohort.MethodsFor a cohort of 26 846 aircrew personnel, standardised mortality ratios (SMR) were calculated. Dose-response analyses were carried out using Poisson regression to assess dose-related cancer risks for the period 1960–2014. Exposure assessment comprises recently available dose register data for all cohort members and newly estimated retrospective cabin crew doses for 1960–2003.ResultsSMR for all-cause, specific cancer groups and most individual cancers were reduced in all aircrew groups. The only increases were seen for brain cancer in pilots (n=23, SMR 2.01, 95% CI 1.15 to 3.28) and for malignant melanoma (n=10, SMR 1.88, 95% CI 0.78 to 3.85). Breast cancer mortality among female cabin crew was similar to the general population (n=71, SMR 1.06, 95% CI 0.77 to 1.44). Overall median cumulative effective dose was 34.2 mSv (max: 116 mSv) for 1960–2014. No dose-response associations were seen in any of the models. For brain cancer, relative risks were elevated across dose categories. An indicative negative trend with increasing dose category was seen for large intestine cancer in female cabin crew (n=23).ConclusionsThere was no evidence for significant dose-response patterns for the considered cancer types. Interpretation of results remains difficult as cumulative dose is closely related to age. Future work should focus on investigating radiation jointly with other risk factors that may contribute to risks for specific cancers among aircrew.
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Liu GS, Cook A, Richardson M, Vail D, Holsinger FC, Oakley-Girvan I. Thyroid cancer risk in airline cockpit and cabin crew: a meta-analysis. CANCERS OF THE HEAD & NECK 2018; 3:7. [PMID: 31093360 PMCID: PMC6460828 DOI: 10.1186/s41199-018-0034-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 07/25/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Airline crew are exposed to ionizing radiation as part of their occupation and have a documented increased risk of melanoma and cataracts. However, whether their occupation predisposes them to an increased risk of thyroid cancer is not established. The purpose of this systematic review and meta-analysis was to assess the risk of thyroid cancer in airline cockpit and cabin crew compared with the general population. METHODS The MEDLINE database accessed via PubMed and Cochrane Database were searched. We included cohort studies reporting the standardized incidence ratio (SIR) or standardized mortality ratio (SMR) of thyroid cancers in any flight-based occupation. RESULTS Of the 1777 citations retrieved in PubMed, eight studies with a total of 243,088 aircrew members and over 3,334,114 person-years of follow-up were included in this meta-analysis. No relevant studies were identified on Cochrane Database. The overall summary SIR of participants in any flight-based occupation was 1.11 (95% CI, 0.79-1.57; p = 0.613; 6 records). The summary SIR for cockpit crew was 1.21 (95% CI, 0.75-1.95; p = 0.383; 4 records) and the summary SIR for cabin crew was 1.00 (95% CI, 0.60-1.66; p = 0.646; 2 records). The overall summary standardized mortality ratio for airline crew was 1.19 (95% CI, 0.59-2.39; p = 0.773; 2 records). CONCLUSION Airline crew were not found to have a significantly elevated risk of thyroid cancer incidence or mortality relative to the general population. Future research should capitalize on the growing occupational cohort dataset and employ innovative methods to quantify lifetime radiation exposure to further assess thyroid cancer risk in airline crew.
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Affiliation(s)
- George S. Liu
- Stanford University School of Medicine, Stanford University, 450 Serra Mall, Stanford, CA 94305 USA
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305 USA
| | - Austin Cook
- Stanford University School of Medicine, Stanford University, 450 Serra Mall, Stanford, CA 94305 USA
| | - Michael Richardson
- Stanford University School of Medicine, Stanford University, 450 Serra Mall, Stanford, CA 94305 USA
| | - Daniel Vail
- Stanford University School of Medicine, Stanford University, 450 Serra Mall, Stanford, CA 94305 USA
| | - F. Christopher Holsinger
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305 USA
| | - Ingrid Oakley-Girvan
- Cancer Prevention Institute of California, Fremont, CA 94538 USA
- Department of Health Research and Policy, the Canary Center at Stanford for Cancer Early Detection and the Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305 USA
- Public Health Institute, Oakland, CA 94607 USA
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Wollschläger D, Hammer GP, Schafft T, Dreger S, Blettner M, Zeeb H. Estimated radiation exposure of German commercial airline cabin crew in the years 1960-2003 modeled using dose registry data for 2004-2015. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2018; 28:275-280. [PMID: 28930297 DOI: 10.1038/jes.2017.21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 07/30/2017] [Indexed: 06/07/2023]
Abstract
Exposure to ionizing radiation of cosmic origin is an occupational risk factor in commercial aircrew. In a historic cohort of 26,774 German aircrew, radiation exposure was previously estimated only for cockpit crew using a job-exposure matrix (JEM). Here, a new method for retrospectively estimating cabin crew dose is developed. The German Federal Radiation Registry (SSR) documents individual monthly effective doses for all aircrew. SSR-provided doses on 12,941 aircrew from 2004 to 2015 were used to model cabin crew dose as a function of age, sex, job category, solar activity, and male pilots' dose; the mean annual effective dose was 2.25 mSv (range 0.01-6.39 mSv). In addition to an inverse association with solar activity, exposure followed age- and sex-dependent patterns related to individual career development and life phases. JEM-derived annual cockpit crew doses agreed with SSR-provided doses for 2004 (correlation 0.90, 0.40 mSv root mean squared error), while the estimated average annual effective dose for cabin crew had a prediction error of 0.16 mSv, equaling 7.2% of average annual dose. Past average annual cabin crew dose can be modeled by exploiting systematic external influences as well as individual behavioral determinants of radiation exposure, thereby enabling future dose-response analyses of the full aircrew cohort including measurement error information.
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Affiliation(s)
- Daniel Wollschläger
- Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Obere Zahlbacher Str. 69, Mainz 55131, Germany
| | - Gaël Paul Hammer
- Registre Morphologique des Tumeurs, Laboratoire National de Santé E.P., Dudelange L-3555, Luxembourg
| | - Thomas Schafft
- Department of Epidemiology & International Public Health, University of Bielefeld, Bielefeld 33501, Germany
| | - Steffen Dreger
- Leibniz Institute for Prevention Research and Epidemiology, Achterstr. 30, Bremen 28359, Germany
| | - Maria Blettner
- Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Obere Zahlbacher Str. 69, Mainz 55131, Germany
| | - Hajo Zeeb
- Leibniz Institute for Prevention Research and Epidemiology, Achterstr. 30, Bremen 28359, Germany
- Health Sciences Bremen, University of Bremen, Bibliotheksstr. 1, Bremen 28359, Germany
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Berwick M, Buller DB, Cust A, Gallagher R, Lee TK, Meyskens F, Pandey S, Thomas NE, Veierød MB, Ward S. Melanoma Epidemiology and Prevention. Cancer Treat Res 2016; 167:17-49. [PMID: 26601858 DOI: 10.1007/978-3-319-22539-5_2] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The epidemiology of melanoma is complex, and individual risk depends on sun exposure, host factors, and genetic factors, and in their interactions as well. Sun exposure can be classified as intermittent, chronic, or cumulative (overall) exposure, and each appears to have a different effect on type of melanoma. Other environmental factors, such as chemical exposures-either through occupation, atmosphere, or food-may increase risk for melanoma, and this area warrants further study. Host factors that are well known to be important are the numbers and types of nevi and the skin phenotype. Genetic factors are classified as high-penetrant genes, moderate-risk genes, or low-risk genetic polymorphisms. Subtypes of tumors, such as BRAF-mutated tumors, have different risk factors as well as different therapies. Prevention of melanoma has been attempted using various strategies in specific subpopulations, but to date optimal interventions to reduce incidence have not emerged.
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Affiliation(s)
- Marianne Berwick
- Department of Internal Medicine, University of New Mexico, MSC10-5550, Albuquerque, NM, 87131-0001, USA.
| | - David B Buller
- Klein Buendel, Inc., 1667 Cole Boulevard, Suite 225, Golden, CO, 80401, USA.
| | - Anne Cust
- Sydney School of Public Health, Sydney Medical School, University of Sydney, Level 6, 119-143 Missenden Road, Camperdown, NSW, 2050, Australia.
| | - Richard Gallagher
- Cancer Control Research Program, BC Cancer Agency, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada.
| | - Tim K Lee
- Cancer Control Research Program, BC Cancer Agency, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada.
| | - Frank Meyskens
- Public Health and Epidemiology, University of California, Irvine, USA.
| | - Shaily Pandey
- Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY, 10029, USA.
| | - Nancy E Thomas
- University of North Carolina, 413 Mary Ellen Jones Bldg. CB#7287, Chapel Hill, NC, 275992, USA.
| | - Marit B Veierød
- Department of Biostatistics, Institute of Basic Medical Sciences, P.O. Box 1122 Blindern, 0317, Oslo, Norway.
| | - Sarah Ward
- Centre for Genetic Origins of Health and Disease (GOHaD), The University of Western Australia, M409, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
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Peterson LE, Kovyrshina T. Adjustment of lifetime risks of space radiation-induced cancer by the healthy worker effect and cancer misclassification. Heliyon 2015; 1:e00048. [PMID: 27441231 PMCID: PMC4945756 DOI: 10.1016/j.heliyon.2015.e00048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/13/2015] [Accepted: 11/10/2015] [Indexed: 01/12/2023] Open
Abstract
Background. The healthy worker effect (HWE) is a source of bias in occupational studies of mortality among workers caused by use of comparative disease rates based on public data, which include mortality of unhealthy members of the public who are screened out of the workplace. For the US astronaut corp, the HWE is assumed to be strong due to the rigorous medical selection and surveillance. This investigation focused on the effect of correcting for HWE on projected lifetime risk estimates for radiation-induced cancer mortality and incidence. Methods. We performed radiation-induced cancer risk assessment using Poisson regression of cancer mortality and incidence rates among Hiroshima and Nagasaki atomic bomb survivors. Regression coefficients were used for generating risk coefficients for the excess absolute, transfer, and excess relative models. Excess lifetime risks (ELR) for radiation exposure and baseline lifetime risks (BLR) were adjusted for the HWE using standardized mortality ratios (SMR) for aviators and nuclear workers who were occupationally exposed to ionizing radiation. We also adjusted lifetime risks by cancer mortality misclassification among atomic bomb survivors. Results. For all cancers combined (“Nonleukemia”), the effect of adjusting the all-cause hazard rate by the simulated quantiles of the all-cause SMR resulted in a mean difference (not percent difference) in ELR of 0.65% and mean difference of 4% for mortality BLR, and mean change of 6.2% in BLR for incidence. The effect of adjusting the excess (radiation-induced) cancer rate or baseline cancer hazard rate by simulated quantiles of cancer-specific SMRs resulted in a mean difference of −1.2% in the all-cancer mortality ELR and mean difference of −6.4% in the mortality BLR. Whereas for incidence, the effect of adjusting by cancer-specific SMRs resulted in a mean change of −14.4% for the all-cancer BLR. Only cancer mortality risks were adjusted by simulated quantiles for misclassification, and results indicate a mean change of 1.1% for all-cancer mortality ELR, while the mean change in the all-cancer PC was approximately 4% for males and 6% for females. Conclusions. The typical life table approach for projecting lifetime risk of radiation-induced cancer mortality and incidence for astronauts and radiation workers can be improved by adjusting for HWE while simulating the uncertainty of input rates, input excess risk coefficients, and bias correction factors during multiple Monte Carlo realizations of the life table.
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Affiliation(s)
- Leif E Peterson
- Center for Biostatistics, Houston Methodist Research Institute, 6565 Fannin Street, Suite MGJ6-031, Houston, TX 77030, United States
| | - Tatiana Kovyrshina
- Center for Biostatistics, Houston Methodist Research Institute, 6565 Fannin Street, Suite MGJ6-031, Houston, TX 77030, United States
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Yong LC, Pinkerton LE, Yiin JH, Anderson JL, Deddens JA. Mortality among a cohort of U.S. commercial airline cockpit crew. Am J Ind Med 2014; 57:906-14. [PMID: 24700478 PMCID: PMC4511278 DOI: 10.1002/ajim.22318] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2014] [Indexed: 11/09/2022]
Abstract
BACKGROUND We evaluated mortality among 5,964 former U.S. commercial cockpit crew (pilots and flight engineers). The outcomes of a priori interest were non-chronic lymphocytic leukemia, central nervous system (CNS) cancer (including brain), and malignant melanoma. METHODS Vital status was ascertained through 2008. Life table and Cox regression analyses were conducted. Cumulative exposure to cosmic radiation was estimated from work history data. RESULTS Compared to the U.S. general population, mortality from all causes, all cancer, and cardiovascular diseases was decreased, but mortality from aircraft accidents was highly elevated. Mortality was elevated for malignant melanoma but not for non-chronic lymphocytic leukemia. CNS cancer mortality increased with an increase in cumulative radiation dose. CONCLUSIONS Cockpit crew had a low all-cause, all-cancer, and cardiovascular disease mortality but elevated aircraft accident mortality. Further studies are needed to clarify the risk of CNS and other radiation-associated cancers in relation to cosmic radiation and other workplace exposures.
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Affiliation(s)
- Lee C. Yong
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio
| | - Lynne E. Pinkerton
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio
| | - James H. Yiin
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio
| | - Jeri L. Anderson
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio
| | - James A. Deddens
- Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio
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Hammer GP, Auvinen A, De Stavola BL, Grajewski B, Gundestrup M, Haldorsen T, Hammar N, Lagorio S, Linnersjö A, Pinkerton L, Pukkala E, Rafnsson V, dos-Santos-Silva I, Storm HH, Strand TE, Tzonou A, Zeeb H, Blettner M. Mortality from cancer and other causes in commercial airline crews: a joint analysis of cohorts from 10 countries. Occup Environ Med 2014; 71:313-22. [PMID: 24389960 DOI: 10.1136/oemed-2013-101395] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Commercial airline crew is one of the occupational groups with the highest exposures to ionising radiation. Crew members are also exposed to other physical risk factors and subject to potential disruption of circadian rhythms. METHODS This study analyses mortality in a pooled cohort of 93 771 crew members from 10 countries. The cohort was followed for a mean of 21.7 years (2.0 million person-years), during which 5508 deaths occurred. RESULTS The overall mortality was strongly reduced in male cockpit (SMR 0.56) and female cabin crews (SMR 0.73). The mortality from radiation-related cancers was also reduced in male cockpit crew (SMR 0.73), but not in female or male cabin crews (SMR 1.01 and 1.00, respectively). The mortality from female breast cancer (SMR 1.06), leukaemia and brain cancer was similar to that of the general population. The mortality from malignant melanoma was elevated, and significantly so in male cockpit crew (SMR 1.57). The mortality from cardiovascular diseases was strongly reduced (SMR 0.46). On the other hand, the mortality from aircraft accidents was exceedingly high (SMR 33.9), as was that from AIDS in male cabin crew (SMR 14.0). CONCLUSIONS This large study with highly complete follow-up shows a reduced overall mortality in male cockpit and female cabin crews, an increased mortality of aircraft accidents and an increased mortality in malignant skin melanoma in cockpit crew. Further analysis after longer follow-up is recommended.
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Affiliation(s)
- Gaël P Hammer
- Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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Brehwens K, Bajinskis A, Haghdoost S, Wojcik A. Micronucleus frequencies and clonogenic cell survival in TK6 cells exposed to changing dose rates under controlled temperature conditions. Int J Radiat Biol 2013; 90:241-7. [PMID: 24350915 DOI: 10.3109/09553002.2014.873831] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE In most exposure scenarios the dose rate of exposure is not constant. Despite this, very little information exists on the possible biological effects of exposing cells to radiation under the conditions of a changing dose rate. The current study highlights interesting effects following exposure under these conditions. MATERIALS AND METHODS We constructed a new exposure facility that allows exposing cells inside an incubator and used it to irradiate human lymphoblastoid TK6 cells both after a moderate (0.48 Gy) and a high (1.1 Gy) dose, where the change in dose rate was, respectively, ≈ 17-fold (2.2-37 mGy/min) and ≈ 39-fold (2.7-106 mGy/min). Clonogenic survival and micronuclei (MN) induction were the chosen endpoints. RESULTS The obtained results confirm the outcome of our first study that TK6 cells exposed to a decreasing dose rate express more MN than cells exposed to an increasing or constant dose rate. The effect was not seen after the moderate dose of 0.48 Gy or detectable at the level of clonogenic cell survival. CONCLUSIONS We speculate that the high level of MN is probably related to a delayed elimination of damaged cells by interphase death, as opposed to mechanisms relating to DNA damage and repair.
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Affiliation(s)
- Karl Brehwens
- Centre for Radiation Protection Research, Department of Molecular Biosciences, the Wenner-Gren Institute, Stockholm University , Stockholm , Sweden
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12
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The relationship between job type and development of cerebral stroke in a large, longitudinal cohort study of workers in a railway company in Japan. Atherosclerosis 2013; 229:217-21. [DOI: 10.1016/j.atherosclerosis.2013.04.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/03/2013] [Accepted: 04/07/2013] [Indexed: 11/20/2022]
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Silva R, Folgosa F, Soares P, Pereira AS, Garcia R, Gestal-Otero JJ, Tavares P, Gomes da Silva MDR. Occupational cosmic radiation exposure in Portuguese airline pilots: study of a possible correlation with oxidative biological markers. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2013; 52:211-220. [PMID: 23412012 DOI: 10.1007/s00411-013-0460-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 02/02/2013] [Indexed: 06/01/2023]
Abstract
Several studies have sought to understand the health effects of occupational exposure to cosmic radiation. However, only few biologic markers or associations with disease outcomes have so far been identified. In the present study, 22 long- and 26 medium-haul male Portuguese airline pilots and 36 factory workers who did not fly regularly were investigated. The two groups were comparable in age and diet, were non-smokers, never treated with ionizing radiation and other factors. Cosmic radiation exposure in pilots was quantified based on direct monitoring of 51 flights within Europe, and from Europe to North and South America, and to Africa. Indirect dose estimates in pilots were performed based on the SIEVERT (Système informatisé d'évaluation par vol de l'exposition au rayonnement cosmique dans les transports aériens) software for 6,039 medium- and 1,366 long-haul flights. Medium-haul pilots had a higher cosmic radiation dose rate than long-haul pilots, that is, 3.3 ± 0.2 μSv/h and 2.7 ± 0.3 μSv/h, respectively. Biological tests for oxidative stress on blood and urine, as appropriate, at two time periods separated by 1 year, included measurements of antioxidant capacity, total protein, ferritin, hemoglobin, creatinine and 8-hydroxy-2-deoxyguanosine (8OHdG). Principal components analysis was used to discriminate between the exposed and unexposed groups based on all the biological tests. According to this analysis, creatinine and 8OHdG levels were different for the pilots and the unexposed group, but no distinctions could be made among the medium- and the long-haul pilots. While hemoglobin levels seem to be comparable between the studied groups, they were directly correlated with ferritin values, which were lower for the airline pilots.
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Affiliation(s)
- Rodrigo Silva
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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14
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Cosmic radiation and mortality from cancer among male German airline pilots: extended cohort follow-up. Eur J Epidemiol 2012; 27:419-29. [DOI: 10.1007/s10654-012-9698-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
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Brehwens K, Bajinskis A, Staaf E, Haghdoost S, Cederwall B, Wojcik A. A new device to expose cells to changing dose rates of ionising radiation. RADIATION PROTECTION DOSIMETRY 2012; 148:366-371. [PMID: 21486830 DOI: 10.1093/rpd/ncr092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In many exposure scenarios to ionising radiation, the dose rate is not constant. Despite this, most in vitro studies aimed at investigating the effects of ionising radiation are carried out exposing samples at constant dose rates. Consequently, very little data exist on the biological effects of exposures to changing dose rates. This may be due to technical limitations of standard irradiation facilities, but also to the fact that the importance of research in this area has not been appreciated. We have recently shown that cells exposed to a decreasing dose rate suffer higher levels of cytogenetic damage than do cells exposed to an increasing or a constant dose rate. To further study the effects of changing dose rates, a new device was constructed that permits the exposure of cell samples in tubes, flasks or Petri dishes to changing dose rates of X-rays. This report presents the technical data, performance and dosimetry of this novel device.
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Affiliation(s)
- Karl Brehwens
- Centre for Radiation Protection Research, GMT Department, Stockholm University, 106 91 Stockholm, Sweden.
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16
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Pinkerton LE, Waters MA, Hein MJ, Zivkovich Z, Schubauer-Berigan MK, Grajewski B. Cause-specific mortality among a cohort of U.S. flight attendants. Am J Ind Med 2012; 55:25-36. [PMID: 21987391 DOI: 10.1002/ajim.21011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2011] [Indexed: 11/09/2022]
Abstract
BACKGROUND We evaluated mortality among 11,311 former U.S. flight attendants. The primary a priori outcomes of interest were breast cancer and melanoma. METHODS Vital status was ascertained through 2007, and life table analyses was conducted. Cumulative exposure to cosmic radiation and circadian rhythm disruption were estimated from work history data and historical published flight schedules. RESULTS All-cause mortality was less than expected among women but was elevated among men, primarily due to elevated HIV-related disease mortality. Mortality from breast cancer among women and melanoma was neither significantly elevated nor related to metrics of exposure. Mortality was elevated for non-Hodgkin's lymphoma among men; for alcoholism, drowning, and intentional self-harm among women; and for railway, water, and air transportation accidents. CONCLUSIONS We found no evidence of increased breast cancer or melanoma mortality. Limitations include reliance on mortality data and limited power resulting from few melanoma deaths and relatively short employment durations.
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Affiliation(s)
- Lynne E Pinkerton
- Industrywide Studies Branch, Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA.
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Cause-specific mortality in professional flight crew and air traffic control officers: findings from two UK population-based cohorts of over 20,000 subjects. Int Arch Occup Environ Health 2011; 85:283-93. [PMID: 21674252 DOI: 10.1007/s00420-011-0660-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Flight crew are exposed to several potential occupational hazards. This study compares mortality rates in UK flight crew to those in air traffic control officers (ATCOs) and the general population. METHODS A total of 19,489 flight crew and ATCOs were identified from the UK Civil Aviation Authority medical records and followed to the end of 2006. Consented access to medical records and questionnaire data provided information on demographic, behavioral, clinical, and occupational variables. Standardized mortality ratios (SMR) were estimated for these two occupational groups using the UK general population. Adjusted mortality hazard ratios (HR) for flight crew versus ATCOs were estimated via Cox regression models. RESULTS A total of 577 deaths occurred during follow-up. Relative to the general population, both flight crew (SMR 0.32; 95% CI 0.30, 0.35) and ATCOs (0.39; 0.32, 0.47) had lower all-cause mortality, mainly due to marked reductions in mortality from neoplasms and cardiovascular diseases, although flight crew had higher mortality from aircraft accidents (SMR 42.8; 27.9, 65.6). There were no differences in all-cause mortality (HR 0.99; 95% CI 0.79, 1.25), or in mortality from any major cause, between the two occupational groups after adjustment for health-related variables, again except for those from aircraft accidents. The latter ratios, however, declined with increasing number of hours. CONCLUSIONS The low all-cause mortality observed in both occupational groups relative to the general population is consistent with a strong "healthy worker effect" and their low prevalence of smoking and other risk factors. Mortality among flight crew did not appear to be influenced by occupational exposures, except for a rise in mortality from aircraft accidents.
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Erren TC, Falaturi P, Morfeld P, Knauth P, Reiter RJ, Piekarski C. Shift work and cancer: the evidence and the challenge. DEUTSCHES ARZTEBLATT INTERNATIONAL 2010; 107:657-62. [PMID: 20953253 DOI: 10.3238/arztebl.2010.0657] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 04/19/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND In 2007, the International Agency for Research on Cancer (IARC) classified shift work with circadian disruption or chronodisruption as a probable human carcinogen. Short-term disturbances of biological 24-hour-rhythms following exposures to light and darkness at unusual times are well-known as "jet-lag" and "shift-lag" symptoms. However, that chronic disturbances or disruptions of timely sequenced circadian rhythms (chronodisruption) should contribute to long-term developments of cancer is a relatively new concept. This review provides background and practical information with regard to the open question "does shift-work cause cancer?" METHODS Overview on the basis of a selective literature search via Medline and ISI Web of Knowledge until 2009 from the viewpoints of occupational medicine, epidemiology, chronobiology, and occupational science. RESULTS The postulated causal links between shift-work and cancer in humans are biologically plausible in the light of experimental findings, but to date we lack epidemiological studies which could describe or exonerate risks in humans. Monetary compensation has already been paid for such cases in at least one country (Denmark). In Germany, however, according to the applicable law, a new occupational disease can only be recognized when certain conditions for the recognition of "general scientific merit" have been met. We present the current state of knowledge regarding prevention. CONCLUSION While causal links between shift-work and cancer developments are not established, future shift-work planning should pay more attention to insights from occupational medicine, chronobiology, and occupational science.
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Affiliation(s)
- Thomas C Erren
- Institut und Poliklinik für Arbeitsmedizin, Umweltmedizin und Präventionsforschung, Universität zu Köln, Köln, Germany.
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19
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Yousif L, Blettner M, Hammer GP, Zeeb H. Testicular cancer risk associated with occupational radiation exposure: a systematic literature review. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2010; 30:389-406. [PMID: 20798474 DOI: 10.1088/0952-4746/30/3/r01] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Testicular cancer is a rare disease, affecting mainly young men aged 15-49. There have been some recent reports that it might be associated with radiation exposure. We have systematically reviewed this topic. English-language articles published between 1990 and 2008 studying the relationship between occupational radiation exposure and testicular cancer were included. Risk of bias was assessed using a modified version of the EPHPP checklist. For ionising radiation we subdivided study populations into occupational groups. No pooled analysis was performed due to the heterogeneity of studies. Seven case-control and 30 cohort studies were included in the review. For radiation workers, one incidence study showed a significant increase and four showed no effect. Eight mortality studies did not indicate an effect while four showed a non-significant increase. Incidence among persons with military exposure was not increased in two studies and non-significantly increased in another two. Among aircrew studies, one showed no effect against five with slight increases. Medical exposure studies showed no increases. For EMF exposure, three studies showed no effect, two reported a significant and four a non-significant increase in incidence. Overall, there was very limited evidence for associations between occupational ionising radiation and testicular cancer, while there were some positive associations for EMF. Testicular cancer mortality is generally low and was not associated with radiation. New incidence studies are recommended to investigate the association between radiation exposure and testicular cancer where exposure is better specified and individually estimated.
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Affiliation(s)
- Lamya Yousif
- Department of Epidemiology, Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany.
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20
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Zeeb H, Hammer GP, Langner I, Schafft T, Bennack S, Blettner M. Cancer mortality among German aircrew: second follow-up. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2010; 49:187-94. [PMID: 19841929 DOI: 10.1007/s00411-009-0248-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 10/04/2009] [Indexed: 05/24/2023]
Abstract
Aircrew members are exposed to cosmic radiation and other specific occupational factors. In a previous analysis of a large cohort of German aircrew, no increase in cancer mortality or dose-related effects was observed. In the present study, the follow-up of this cohort of 6,017 cockpit and 20,757 cabin crew members was extended by 6 years to 2003. Among male cockpit crew, the resulting all-cancer standardized mortality ratio (SMR) (n = 127) is 0.6 (95% CI 0.5-0.8), while for brain tumors it is 2.1 (95% CI 1.0-3.9). The cancer risk is significantly raised (RR = 2.2, 95% CI 1.2-4.1) among cockpit crew members employed 30 years or more compared to those employed less than 10 years. Among both female and male cabin crew, the all-cancer SMR and that for most individual cancers are close to 1. The SMR for breast cancer among female crew is 1.2 (95% CI 0.8-1.8). Non-Hodgkin's Lymphoma among male cabin crew is increased (SMR 4.2; 95% CI 1.3-10.8). However, cancers associated with radiation exposure are not raised in the cohort. It is concluded that among cockpit crew cancer mortality is low, particularly for lung cancer. The positive trend of all cancer with duration of employment persists. The increased brain cancer SMR among cockpit crew requires replication in other cohorts. For cabin crew, cancer mortality is generally close to population rates. Cosmic radiation dose estimates will allow more detailed assessments, as will a pooling of updated aircrew studies currently in planning.
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Affiliation(s)
- Hajo Zeeb
- Institute of Medical Biostatistics, Epidemiology & Informatics, University Medical Center, University of Mainz, 55131, Mainz, Germany.
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21
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Hammer GP, Blettner M, Zeeb H. Epidemiological studies of cancer in aircrew. RADIATION PROTECTION DOSIMETRY 2009; 136:232-239. [PMID: 19608578 DOI: 10.1093/rpd/ncp125] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposure to cosmic ionising radiation, in addition to other specific occupational risks, is of concern to aircrew members. Epidemiological studies provide an objective way to assess the health of this occupational group. We systematically reviewed the epidemiological literature on health of aircrew members since 1990, focusing on cancer as the endpoint of interest. Sixty-five relevant publications were identified and reviewed. Whereas overall cancer incidence and mortality was generally lower than in the comparison population, consistently elevated risks were reported for breast cancer incidence in female aircrew members and for melanoma in both male and female aircrew members. Brain cancer was increased in some studies among pilots. Occasionally trends of increasing cancer mortality or incidence with increasing estimated radiation dose were reported. Ionising radiation is considered to contribute little if at all to the elevated risks for cancers among aircrew, whereas excess ultraviolet radiation is a probable cause of the increased melanoma risk.
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Affiliation(s)
- Gaël P Hammer
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center, Johannes Gutenberg-University, Langenbeckstr. 1, D-55101 Mainz, Germany.
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22
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Telle-Lamberton M. [Epidemiologic data on radiation-induced breast cancer]. Rev Epidemiol Sante Publique 2008; 56:235-43. [PMID: 18672338 DOI: 10.1016/j.respe.2008.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 05/22/2008] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Female breast cancer is the most frequent cancer, both in incidence and mortality. It is well known that exposure to ionizing radiation increases the risk, but some questions remain concerning low dose and low-dose rate effects and cofactors. These potential effects have to be taken into account to carry out adequate risk assessment on medically exposed populations. A literature review is proposed on this issue. METHODS A Medline search was undertaken. Keywords used were ionizing radiation, breast cancer and epidemiology. More studies were added through references included in the first list of articles. The focus was placed on studies including quantitative dose-effect relationship analyses. RESULTS A latency of five to 10 to 13 years is observed in the appearance of risk. The risk diminishes with age at exposure. A diminution with age at risk is also suspected. The excess relative risk per gray varies between 0.3 and 1.5 for an age at first exposure of 25 years. The study of Hiroshima and Nagasaki survivors shows that risk is increased even if doses are restricted to below 0.5Gy. Above high doses (20Gy), the risk no longer increases. This can be interpreted as a cell-killing effect. The excess subsists if doses are fractionated, but a diminution of the effect is suspected. CONCLUSION The effects of exposure to levels of doses used for medical diagnostic are very difficult to study in the general population by epidemiological methods. Only studies conducted on very young children could achieve enough power, because of their high radiosensitivity. Available information on the effects of doses above 0.5Gy allows extrapolation on maximal effects. Models deduced from existing cohorts can be used to assess risk, with their limits due to associated uncertainties. Preston et al. proposed an excess absolute-risk model, which makes estimates from the more comprehensive cohorts compatible. This model has been retained by the 2006 committee "Biological effects of ionizing radiation" (report VII).
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Affiliation(s)
- M Telle-Lamberton
- Direction de la radioprotection de l'homme, institut de radioprotection et de sûreté nucléaire, BP 17, 92262 Fontenay-aux-Roses, France.
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23
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24
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Chronodisruption and cancer. Naturwissenschaften 2008; 95:367-82. [DOI: 10.1007/s00114-007-0335-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/22/2007] [Accepted: 12/04/2007] [Indexed: 10/22/2022]
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Silver SR, Hiratzka SL, Schubauer-Berigan MK, Daniels RD. Chronic lymphocytic leukemia radiogenicity: a systematic review. Cancer Causes Control 2007; 18:1077-93. [PMID: 17694421 DOI: 10.1007/s10552-007-9048-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 07/19/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Chronic lymphocytic leukemia (CLL) is generally considered to be non-radiogenic and is excluded from several programs that compensate workers for illnesses resulting from occupational exposures. Questions about whether this exclusion is justified prompted a Congressional mandate to the National Institute for Occupational Safety and Health (NIOSH) to, further, examine the radiogenicity of CLL. This study revisits the question of CLL radiogenicity by examining epidemiologic evidence from occupationally and medically-exposed populations. METHODS A systematic review of radiation-exposed cohorts was conducted to investigate the association between radiation and CLL. Exploratory power calculations for a pooled occupational study were performed to examine the feasibility of assessing CLL radiogenicity epidemiologically. RESULTS There is a bias against reporting CLL results, because of the disease's presumed non-radiogenicity. In medical cohort studies that provide risk estimates for CLL, risk is elevated, though non-significantly, in almost all studies with more than 15 years average follow-up. The results of occupational studies are less consistent. CONCLUSIONS Studies with adequate follow-up time and power are needed to better understand CLL radiogenicity. Power analyses show that a pooled study might detect risk on the order of radiation induced non-CLL leukemia, but is unlikely to detect smaller risks.
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Affiliation(s)
- Sharon R Silver
- Division of Surveillance, Hazard Evaluations, and Field Studies (DSHEFS), National Institute for Occupational Safety and Health (NIOSH), Cincinnati, OH, USA.
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26
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Telle-Lamberton M. Les études épidémiologiques sur les travailleurs exposés aux faibles doses de rayonnements ionisants. ARCH MAL PROF ENVIRO 2005. [DOI: 10.1016/s1775-8785(05)79055-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Nearly 20 epidemiologic or related studies of cancer incidence and mortality have been published during or since 2000, with several reporting increased risks of female breast cancer among flight attendants and melanoma among both pilots and cabin crew. Occasionally, excesses of other cancers have been observed, but not consistently. Although the real causes of these excess cancer risks are not known, there is concern that they may be related to occupational exposures to ionizing radiation of cosmic origin. It is possible that confounding risk factors may partially or totally explain the observed relationships, but several investigations are beginning to address lack of past adjustment for reproductive factors and sun exposure with improved study designs. With progress in aviation technology, planes will fly longer and at higher altitudes, and presumably the number of flights and passengers will increase. To respond responsibly to the real and perceived risks associated with flying, more extensive data are needed, but special efforts should be considered to ensure new projects can genuinely add to our current knowledge.
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Affiliation(s)
- Alice J Sigurdson
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-7238, USA.
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Langner I, Blettner M, Gundestrup M, Storm H, Aspholm R, Auvinen A, Pukkala E, Hammer GP, Zeeb H, Hrafnkelsson J, Rafnsson V, Tulinius H, De Angelis G, Verdecchia A, Haldorsen T, Tveten U, Eliasch H, Hammar N, Linnersjö A. Cosmic radiation and cancer mortality among airline pilots: results from a European cohort study (ESCAPE). RADIATION AND ENVIRONMENTAL BIOPHYSICS 2004; 42:247-256. [PMID: 14648170 DOI: 10.1007/s00411-003-0214-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 10/16/2003] [Indexed: 05/24/2023]
Abstract
Cosmic radiation is an occupational risk factor for commercial aircrews. In this large European cohort study (ESCAPE) its association with cancer mortality was investigated on the basis of individual effective dose estimates for 19,184 male pilots. Mean annual doses were in the range of 2-5 mSv and cumulative lifetime doses did not exceed 80 mSv. All-cause and all-cancer mortality was low for all exposure categories. A significant negative risk trend for all-cause mortality was seen with increasing dose. Neither external and internal comparisons nor nested case-control analyses showed any substantially increased risks for cancer mortality due to ionizing radiation. However, the number of deaths for specific types of cancer was low and the confidence intervals of the risk estimates were rather wide. Difficulties in interpreting mortality risk estimates for time-dependent exposures are discussed.
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Affiliation(s)
- I Langner
- School of Public Health, Division of Epidemiology and Medical Statistics, University of Bielefeld, P.O. Box 100 131, 33501 Bielefeld, Germany.
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Qiang Y, Baker SP, Rebok GW, McCarthy ML, Li G. Mortality Risk in a Birth Cohort of Commuter Air Carrier and Air Taxi Pilots. J Occup Environ Med 2003; 45:1297-302. [PMID: 14665816 DOI: 10.1097/01.jom.0000099985.06466.fc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Commuter and air taxi pilots have higher work-related death rates than most other occupational groups. In this longitudinal study, the authors examined the mortality in a cohort of 3263 commuter and air taxi pilots. With adjustment for age, proportional hazards modeling revealed that termination or downgrading of medical certificates during the 11-year follow-up was associated with a significantly increased risk of overall mortality (relative risk, 2.32; 95% confidence interval [CI] = 1.43-3.77). Relative to the general population with similar demographic characteristics, commuter air carrier and air taxi pilots had significantly lower overall mortality (standard mortality ratio [SMR], 0.36; 95% CI = 0.32-0.41) and mortality from cardiovascular diseases (SMR, 0.18, 95% CI = 0.15-0.22), but considerably higher mortality from aviation crashes (SMR, 128.88; 95% CI = 6.35-2624.36). The results indicate that the current medical certification system is effective in maintaining a healthy pilot workforce.
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Affiliation(s)
- Yandong Qiang
- Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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30
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Blettner M, Zeeb H, Auvinen A, Ballard TJ, Caldora M, Eliasch H, Gundestrup M, Haldorsen T, Hammar N, Hammer GP, Irvine D, Langner I, Paridou A, Pukkala E, Rafnsson V, Storm H, Tulinius H, Tveten U, Tzonou A. Mortality from cancer and other causes among male airline cockpit crew in Europe. Int J Cancer 2003; 106:946-52. [PMID: 12918075 DOI: 10.1002/ijc.11328] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Airline pilots and flight engineers are exposed to ionizing radiation of cosmic origin and other occupational and life-style factors that may influence their health status and mortality. In a cohort study in 9 European countries we studied the mortality of this occupational group. Cockpit crew cohorts were identified and followed-up in Denmark, Finland, Germany, Great Britain, Greece, Iceland, Italy, Norway and Sweden, including a total of 28,000 persons. Observed and expected deaths for the period 1960-97 were compared based on national mortality rates. The influence of period and duration of employment was analyzed in stratified and Poisson regression analyses. The study comprised 547,564 person-years at risk, and 2,244 deaths were recorded in male cockpit crew (standardized mortality ratio [SMR] = 0.64, 95% confidence interval [CI] = 0.61-0.67). Overall cancer mortality was decreased (SMR = 0.68; 95% CI = 0.63-0.74). We found an increased mortality from malignant melanoma (SMR = 1.78, 95% CI = 1.15-2.67) and a reduced mortality from lung cancer (SMR = 0.53, 95% CI = 0.44-0.62). No consistent association between employment period or duration and cancer mortality was observed. A low cardiovascular mortality and an increased mortality caused by aviation accidents were noted. Our study shows that cockpit crew have a low overall mortality. The results are consistent with previous reports of an increased risk of malignant melanoma in airline pilots. Occupational risk factors apart from aircraft accidents seem to be of limited influence with regard to the mortality of cockpit crew in Europe.
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Affiliation(s)
- Maria Blettner
- School of Public Health, Division of Epidemiology and Medical Statistics, University of Bielefeld, Bielefeld, Germany.
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