How much significantly higher is the risk? One study does not make a risk. The study does not seem to mention the effect on patients.
To choose the survivors of the atomic bombs on Japan as the "primary basis" for this study seems dubious. This is an extreme choice for a basis.
What would be the consequences? Fewer medical imaging studies? Are there too many such studies?
"Long-term exposure to low-dose radiation is linked to an increased risk of cancer, according to a study led by the University of California, Irvine. In the U.S., radiation exposure for the average person doubled between 1985 and 2006, mainly from medical imaging procedures such as CT scans, highlighting the need for its judicious use."
"... No patients were involved in setting the research question, the outcome measures, or the design and implementation of the study. ...
The study of Japanese survivors of the atomic bombs serves as the primary basis for the quantitative risk estimates used in radiation protection. ..."
The study of Japanese survivors of the atomic bombs serves as the primary basis for the quantitative risk estimates used in radiation protection. ..."
From the abstract:
"Abstract
Objective To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer.
Design Multinational cohort study.
Setting Cohorts of workers in the nuclear industry in France, the UK, and the US included in a major update to the International Nuclear Workers Study (INWORKS).
Participants
309 932 workers with individual monitoring data for external exposure to ionising radiation and a total follow-up of 10.7 million person years.
309 932 workers with individual monitoring data for external exposure to ionising radiation and a total follow-up of 10.7 million person years.
Main outcome measures
Estimates of excess relative rate per gray (Gy) of radiation dose for mortality from cancer.
Estimates of excess relative rate per gray (Gy) of radiation dose for mortality from cancer.
Results
The study included 103 553 deaths, of which 28 089 were due to solid cancers. The estimated rate of mortality due to solid cancer increased with cumulative dose by 52% (90% confidence interval 27% to 77%) per Gy, lagged by 10 years. Restricting the analysis to the low cumulative dose range (0-100 mGy) approximately doubled the estimate of association (and increased the width of its confidence interval), as did restricting the analysis to workers hired in the more recent years of operations when estimates of occupational external penetrating radiation dose were recorded more accurately. Exclusion of deaths from lung cancer and pleural cancer had a modest effect on the estimated magnitude of association, providing indirect evidence that the association was not substantially confounded by smoking or occupational exposure to asbestos.
The study included 103 553 deaths, of which 28 089 were due to solid cancers. The estimated rate of mortality due to solid cancer increased with cumulative dose by 52% (90% confidence interval 27% to 77%) per Gy, lagged by 10 years. Restricting the analysis to the low cumulative dose range (0-100 mGy) approximately doubled the estimate of association (and increased the width of its confidence interval), as did restricting the analysis to workers hired in the more recent years of operations when estimates of occupational external penetrating radiation dose were recorded more accurately. Exclusion of deaths from lung cancer and pleural cancer had a modest effect on the estimated magnitude of association, providing indirect evidence that the association was not substantially confounded by smoking or occupational exposure to asbestos.
Conclusions
This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world’s most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings."
This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world’s most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings."
UC Irvine-led study links low-dose radiation to higher cancer risk Caution warranted given increased public exposure in recent decades
What is wrong with the chart below? Use of linear regression, while nonlinear is strongly suggested by the data. One may also notice the the confidence intervals are spreading enormously beyond 250 mGy.
Fig 1 Relative rate of mortality due to solid cancer by categories of cumulative colon dose, lagged 10 years in INWORKS. Bars indicate 90% confidence intervals, and purple line depicts fitted linear model for change in excess relative rate of solid cancer mortality with dose. Strata: country, age, sex, birth cohort, socioeconomic status, duration employed, neutron monitoring status
No comments:
Post a Comment