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RE: [cdn-nucl-l] Low level radiation and cancer: BAD NEWS
Here's an interesting comment from Radsafe....
Note especially the points about lung cancer/ smoking, about the Canadian
portion of the database, and the ASSUMED dose-response model -- LNT.
Jaro
^^^^^^^^^^^^^^^^^^^^^
-----Original Message-----
From: radsafe-bounces@radlab.nl [mailto:radsafe-bounces@radlab.nl]On Behalf
Of Otto G. Raabe
Sent: Wednesday, June 29, 2005 5:12 PM
To: A Karam; Fred Dawson; radsafe@radlab.nl
Subject: RE: [ RadSafe ] BBC Reports "Nuclear workers' cancer risk rise
June 29, 2005
Today's publication on the British Medical Journal of the paper "Risk of
cancer after low doses of ionizing radiation:retrospective cohort study in
15 counties" by Cardis, and 49 other prominent authors promises to be
treated as the definitive study of radiation-induced cancer among radiation
workers. The is probably the most reliable of all the radiation worker
epidemiology studies because of its size and excellently qualified and
unbiased authors. A cohort of 407,391 radiation workers in Canada, Sweden,
the United Kingdom, and the United States. It concludes that "...1-2% of
deaths from cancer among workers in this cohort may be attributable to
radiation." It concludes that the findings are consistent with the linear
risk estimates obtained from the RERF studies of Atomic Bomb survivors.
A reading of the paper shows that there was a significant increase in solid
cancer cases (increased relative risk of 0.97 with 95% confidence range
from 0.14-0.97) in radiation workers based on a linear dose-response model.
(Leukemia was not significantly increased.) The shape of the dose-response
curve is, therefore, uncertain since these results may be driven by cancer
in the most highly exposed workers. There is no independent control group
in the study.
When lung cancer is separated from the other solid cancers, there is no
significant increase in cancer rate for all the other types of cancers
combined. Although the researchers cite reasons for assuming that the
results are not seriously affected by smoking, almost all lung cancer is
caused by cigarette smoking and it may not be possible to appropriately
correct these data for the action of this strong carcinogen among the
workers. The Canadian cohort was the only cohort reported that showed a
significantly increased cancer risk. If the Canadian data are omitted, the
data from the other 14 countries did not demonstrate a significant increase
in cancer rates as a function of radiation dose.
Even though this is a well-done study it depends on a linear model and its
main conclusion is depends on assuming that lung cancer rates are not
confounded by smoking or other possible factors among the workers.
Otto
**********************************************
Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
(Street Address: Bldg. 3792, Old Davis Road)
University of California, Davis, CA 95616
E-Mail: ograabe@ucdavis.edu
Phone: (530) 752-7754 FAX: (530) 758-6140
***********************************************
===============
From: Jaro [mailto:jaro-10kbq@sympatico.ca]
Sent: Wednesday, June 29, 2005 6:58 PM
To: cdn-nucl-l@mailman1.cis.mcmaster.ca
Subject: RE: [cdn-nucl-l] Low level radiation and cancer: BAD NEWS
Better yet :
http://bmj.bmjjournals.com/cgi/rapidpdf/bmj.38499.599861.E0v1.pdf
The paper uses - in part - the same Canadian ARW data set that was cited in
this report :
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Ab
stract&list_uids=15161357&query_hl=1
Analysis of mortality among Canadian nuclear power industry workers after
chronic low-dose exposure to ionizing radiation, in Radiat Res. 2004
Jun;161(6):633-41.
by Zablotska LB, Ashmore JP, Howe GR.
.....whose findings have been summarised by others in the graph (image) I
posted at
http://www.cns-snc.ca/branches/quebec/reactions/CFCF_vanderHeyden_2005_May_1
6.html
....it comes from a Hydro-Quebec presentation (in French) to the public
hearings of Quebec's BAPE ("Bureau d'audiences publiques sur
l'environnement"), posted at
http://www.bape.gouv.qc.ca/sections/mandats/gentilly-2/documents/DA17.pdf
.....obviously, the cancer risk for Canadian ARWs is low, below the 1.0
reference for the entire population, but presumably it will catch up, as the
group ages.
Having done the age-adjustments, etc., the new international study came up
with their results, illustrated in the graph below - in which the Canadian
cohort appears to skew the overall results in a noticeable way :
Comments welcome ! (I notice that BH is one of the co-authors)
Jaro
^^^^^^^^^^^^^^^^^^^^^
-----Original Message-----
From: cdn-nucl-l-admin@mailman1.cis.McMaster.CA
[mailto:cdn-nucl-l-admin@mailman1.cis.McMaster.CA]On Behalf Of
Muckerheide, James
Sent: Wednesday, June 29, 2005 4:49 PM
To: Dukelow, James S Jr; cdn-nucl-l@mailman1.cis.mcmaster.ca
Subject: RE: [cdn-nucl-l] Low level radiation and cancer: BAD NEWS
"Online First" - in the left column.
Does anyone know if your responsible organization (or others) will undertake
a credible review of this?
Regards, Jim Muckerheide
________________________________
From: cdn-nucl-l-admin@mailman1.cis.McMaster.CA on behalf of Dukelow, James
S
Jr
Sent: Wed 6/29/2005 4:44 PM
To: Andrew Daley; Cdn-Nucl-LISTSERV (E-mail)
Subject: RE: [cdn-nucl-l] Low level radiation and cancer: BAD NEWS
For the "international" study, go to www.bmj.org and click on Online
Publication (or words to that effect).
Best regards.
Jim Dukelow
Pacific Northwest National Laboratory
Richland, WA
jim.dukelow@pnl.gov
-----Original Message-----
From: cdn-nucl-l-admin@mailman1.cis.McMaster.CA
[mailto:cdn-nucl-l-admin@mailman1.cis.McMaster.CA] On Behalf Of Andrew Daley
Sent: Wednesday, June 29, 2005 1:29 PM
To: Cdn-Nucl-LISTSERV (E-mail)
Subject: [cdn-nucl-l] Low level radiation and cancer: BAD NEWS
Anybody have a link to the French study? Jerry can you comment on the
validity of this study??
Low-dose radiation poses small cancer risk: report
Last Updated Wed, 29 Jun 2005 15:39:56 EDT
CBC News < http://www.cbc.ca/news/credit.html >
There is likely no such thing as a safe level of exposure to radiation,
although cancer is rarely induced by low doses, a panel of U.S. scientists
said Wednesday.
"The scientific research base shows that there is no threshold of exposure
below which low levels of ionized radiation can be demonstrated to be
harmless or beneficial," said Richard Monson, the panel's chair and a
professor of epidemiology at Harvard's School of Public Health.
"The health risks - particularly the development of solid cancers in
organs -
rise proportionally with exposure."
The panel's report addresses amounts of radiation from medical treatments
such as full-body CT scans. The findings are expected to affect government
safety recommendations in the U.S.
A low dose of 100 millisieverts of radiation - the equivalent of 10 chest
X-rays - is expected to cause solid cancer or leukemia in one out of 100
people over a lifetime, the report said. About half of those cases could be
fatal.
The panel's report updates research based largely on survivors of the 1945
atomic bomb attacks in Japan.
While medical radiation is often appropriate, "exposure to any unnecessary
radiation should be avoided," Monson told a news conference. "And what is
unnecessary is up to an individual."
Natural sources of radiation such as gamma rays from space and radon in the
environment account for about 82 per cent of our exposure, the report said.
More research is needed on those who receive frequent doses such as
full-body
CT scans, and on children who get X-rays or radiation treatment for cancer,
the panel said.
Research on more than 400,000 nuclear industry workers found they had a 10
per cent higher risk of death from cancer, according to a related report
released Wednesday by the International Agency for Research on Cancer in
France.
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