5 results on '"Muirhead CR"'
Search Results
2. Cerebrovascular diseases in nuclear workers first employed at the Mayak PA in 1948-1972.
- Author
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Azizova TV, Muirhead CR, Moseeva MB, Grigoryeva ES, Sumina MV, O'Hagan J, Zhang W, Haylock RJ, and Hunter N
- Subjects
- Adult, Aged, Alpha Particles adverse effects, Cerebrovascular Disorders etiology, Cerebrovascular Disorders mortality, Cohort Studies, Female, Follow-Up Studies, Gamma Rays adverse effects, Humans, Male, Middle Aged, Radiation Dosage, Risk, Russia epidemiology, Young Adult, Cerebrovascular Disorders epidemiology, Nuclear Power Plants, Occupational Exposure adverse effects
- Abstract
Incidence and mortality from cerebrovascular diseases (CVD) (430-438 ICD-9 codes) have been studied in a cohort of 18,763 workers first employed at the Mayak Production Association (Mayak PA) in 1948-1972 and followed up to the end of 2005. Some of the workers were exposed to external gamma-rays only while others were exposed to a mixture of external gamma-rays and internal alpha-particle radiation due to incorporated (239)Pu. After adjusting for non-radiation factors, there were significantly increasing trends in CVD incidence with total absorbed dose from external gamma-rays and total absorbed dose to liver from internal alpha radiation. The CVD incidence was statistically significantly higher among workers with total absorbed external gamma-ray doses greater than 0.20 Gy compared to those exposed to lower doses; the data were consistent with a linear trend in risk with external dose. The CVD incidence was statistically significantly higher among workers with total absorbed internal alpha-radiation doses to liver from incorporated (239)Pu greater than 0.025 Gy compared to those exposed to lower doses. There was no statistically significant trend in CVD mortality risk with either external gamma-ray dose or internal alpha-radiation dose to liver. The risk estimates obtained are generally compatible with those from other large occupational studies, although the incidence data point to higher risk estimates compared to those from the Japanese A-bomb survivors. Further studies of the unique cohort of Mayak workers chronically exposed to external and internal radiation will allow improving the reliability and validating the radiation safety standards for occupational and public exposure.
- Published
- 2011
- Full Text
- View/download PDF
3. Possible selection effects for radiation risk estimates in Japanese A-bomb survivors: reanalysis of acute radiation symptoms data.
- Author
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Hunter N, Muirhead CR, and Zhang W
- Subjects
- Adult, Aged, Cohort Studies, Humans, Japan, Leukemia, Radiation-Induced epidemiology, Leukemia, Radiation-Induced mortality, Middle Aged, Neoplasms, Radiation-Induced epidemiology, Neoplasms, Radiation-Induced mortality, Poisson Distribution, Radiation, Radiation Dosage, Radioactive Fallout, Risk, Sex Factors, Survivors, Nuclear Warfare
- Abstract
An earlier analysis examined the possibility of bias in the Life Span Study (LSS) cohort by studying Japanese A-bomb survivors with bomb-related acute injuries and those without such injuries. The authors reported significantly higher radiation risks, both for cancers and non-cancers, among those survivors with acute injuries compared with those without. The risks were reported to be particularly large among survivors aged <10 or > or =55 years of age at the time of bombings. The aim of this paper is to examine these findings more closely using the LSS acute effects data. All the analyses were carried out using Poisson regression. Relative risk models were fitted with adjustment for sex and other factors. Significant differences in relative risk between survivors with epilation and burns and those without epilation and burns are found for leukaemia. There is also some evidence for heterogeneity in the leukaemia risk between survivors with two or more acute injuries and those with no injuries, but the evidence is disappeared when survivors with one or more injuries are compared with those without injuries. For solid cancers, cardiovascular disease and all deaths combined, the risks do not differ to a statistically significant extent between survivors with and without injuries. There is no statistically significant heterogeneity in risk across age-at-exposure categories for survivors with injuries. For all deaths combined, relative risk estimates and their uncertainties are significantly higher for survivors exposed at ages <10 years when compared with other exposure ages, but risks are not significantly raised for survivors exposed at > or =55 years of age. With the exception of leukaemia, the findings from the present work are inconsistent with those of Stewart and Kneale.
- Published
- 2006
- Full Text
- View/download PDF
4. Fitting the two-stage model of carcinogenesis to nested case-control data on the Colorado Plateau uranium miners: dependence on data assumptions.
- Author
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Haylock RG and Muirhead CR
- Subjects
- Case-Control Studies, Cocarcinogenesis, Cohort Studies, Colorado epidemiology, Humans, Lung Neoplasms etiology, Male, Neoplasms, Radiation-Induced etiology, Radon adverse effects, Smoking adverse effects, Smoking epidemiology, Lung Neoplasms epidemiology, Mining, Models, Biological, Neoplasms, Radiation-Induced epidemiology, Occupational Exposure, Uranium
- Abstract
This paper investigates some problems with the Colorado Plateau uranium miners cohort when fitting the mechanistic model of carcinogenesis of Moolgavkar et al. (MVK model) to nested case-control data for lung cancers. The influence of data for hard rock mining and work histories on the model fitting is examined and found to be highly influential. The question of selecting the most appropriate number of controls per case is also considered. Analyses were carried out assuming that the hard rock mining exposure occurred prior to all other work histories and that miners received no exposure between work histories. The use of less than 15 controls per case was found to seriously restrict the quality of fit of the models. The best fitting, most reliable model contained linear effects of radon exposure on the first mutation rate, the rate of differentiation, and the rate of death of the intermediate cells. An effect of smoking on the growth of the intermediate cells was also included in the model. It is concluded that owing to the complexity of the MVK model and the limited amount of information in this dataset, the reliability of the Colorado Plateau dataset for fitting this type of model, particularly in a case-control format, is questionable.
- Published
- 2004
- Full Text
- View/download PDF
5. Relative risks of radiation-associated cancer: comparison of second cancer in therapeutically irradiated populations with the Japanese atomic bomb survivors.
- Author
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Little MP, Muirhead CR, Haylock RG, and Thomas JM
- Subjects
- Female, Humans, Japan, Male, Risk, Neoplasms, Radiation-Induced etiology, Neoplasms, Second Primary etiology, Nuclear Warfare, Radiotherapy adverse effects
- Abstract
In this paper the radiation-associated relative risks of second primary cancer incidence in groups treated for first primary cancer by radiotherapy are compared with radiation-associated relative risk estimates in the Japanese atomic bomb survivor cancer incidence data. For four cancer sites, namely lung cancer, bone cancer, ovarian cancer and leukaemia, the relative risks in the comparable (age at exposure, time since exposure, sex matched) subsets of the Japanese data are significantly greater than those in the majority of second cancer studies. Even when the differences between the relative risks in the Japanese atomic bomb survivors and the medical series do not approach conventional levels of statistical significance, relative risks tend to be higher in the Japanese data than in the second cancer studies. At least for leukaemia, the discrepancy between the Japanese and second cancer risks can be largely explained by cell-sterilisation effects. There are few indications of modification of radiation-associated second cancer relative risk among those treated with adjuvant chemotherapy, nor are there strong indications of modification of radiation-associated relative risk by heritable genetic factors. If anything, there is evidence that second cancer relative excess risks are lower among those patients with cancer-prone disorders than among non-susceptible patients. However, the higher underlying cancer risk in some of these medically exposed populations should also be considered, in particular for those with cancer-prone conditions, so that the absolute excess risk is sometimes higher than in the Japanese data.
- Published
- 1999
- Full Text
- View/download PDF
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