Wednesday, June 29, 2005

BEIR VII Released

As the Washington Post and other press sources are reporting, the National Academy of Science's Committee on the Biological Effects of Ionizing Radiation ("BEIR") has released a long-awaited report on the health effects of exposure to low radiation doses. From the NAS press release:
The study committee defined low doses as those ranging from nearly zero to about 100 millisievert (mSv) -- units that measure radiation energy deposited in living tissue. The radiation dose from a chest X-ray is about 0.1 mSv. In the United States, people are exposed on average to about 3 mSv of natural "background" radiation annually.

The committee's report develops the most up-to-date and comprehensive risk estimates for cancer and other health effects from exposure to low-level ionizing radiation. In general, the report supports previously reported risk estimates for solid cancer and leukemia, but the availability of new and more extensive data have strengthened confidence in these estimates.

Specifically, the committee's thorough review of available biological and biophysical data supports a "linear, no-threshold" (LNT) risk model, which says that the smallest dose of low-level ionizing radiation has the potential to cause an increase in health risks to humans. In the past, some researchers have argued that the LNT model exaggerates adverse health effects, while others have said that it underestimates the harm. The preponderance of evidence supports the LNT model, this new report says.

"The scientific research base shows that there is no threshold of exposure below which low levels of ionizing radiation can be demonstrated to be harmless or beneficial," said committee chair Richard R. Monson, associate dean for professional education and professor of epidemiology, Harvard School of Public Health, Boston. "The health risks – particularly the development of solid cancers in organs – rise proportionally with exposure. At low doses of radiation, the risk of inducing solid cancers is very small. As the overall lifetime exposure increases, so does the risk." The report is the seventh in a series on the biological effects of ionizing radiation.
A summary report (PDF) is available here; the full report, here. You can also listen (via Real Player) to the committee's news conference.


Pat Broudy writes ...

My name is Pat Broudy. I am the national legislative director of the National Association of Atomic Veterans. I have listened to the oral presentation by the committee responsible for BEIR VII. There was not one mention by the committee members, nor were there any by the questioners, regarding the several hundred thousand atomic veterans exposed to ionizing radiation by our government during the Cold War. I wonder why that was not an issue, or did the committee consider the men/women deliberately exposed to ionizing radiation, and then sworn to secrecy a "throw-away" segment of society, as well as the Downwinders and uranium miners.

8:50 PM  
Lisa writes ...

Just by living, we are exposed to harmful radiation. If the study is accurate, then we should strive to lower the sources of additional radiation exposure.

I had read an interesting study of a region in India, Kerala. The people living there are exposed to 7.5 times the average radiation levels due to an increase of radiation in the soil there. I believe several studies have been attempted to assess the health effects that might be caused by the additional radiation exposure to the people living in the region. The scientists couldn't draw conclusive evidence that these people developed health problems (i.e. cancer) due to the radiation.

Perhaps they have adapted? It's interesting.

I do hope the study you cite prompts further limits on radiation.

1:27 PM  
Anonymous writes ...

My name is Peter Briscoe I am a radiologist from Australia and i am still unconvinced that cancer statistics derived from A bomb survivors can be used to support the LND MODEL being pushed by the BEIRV11 report.These people could now be up to 1oo yrs old so it could be said that low doses of radiation have a beneficial effect in this cohort.Lisa correctly points out the study of people in Kerala India with high background doses having no increased cancer rates.They are also among the longest living most intelligent groups in that country,does low dose radiation increase intelligence & longevity? The British Radiologists group & many others support no increased risk for cancer at low dose with weak evidence for increased longevity in these groups.In this era of energy crisis we should be very wary of propogating radiation phobia as hysteria is already the norm as presented in the media usually by people with an anti scince agenda

11:40 PM  

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