[ RadSafe ] " Nuclear workers: low radiation dose linked tosmall increased r isk of cancer "

[Jaro]

-----Original Message-----
From: Sandy Perle
Sent: Tuesday, June 28, 2005 5:47 PM

Other studies in the US power reactor population show the opposite.
When the probablilty is shown to be lower than for the general
public, the term "healthy worker effect" is thrown out. You can't win!
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I don't know if I would call it a "healthy worker effect" -- its pretty
obvious that cancer is an old-age disease, and that by definition retired
folks aren't "workers" - nuclear or otherwise.

The national study I was refering to was this one :

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Ab
stract&list_uids=15161357&query_hl=1
Radiat Res. 2004 Jun;161(6):633-41.
Analysis of mortality among Canadian nuclear power industry workers after
chronic low-dose exposure to ionizing radiation.

Zablotska LB, Ashmore JP, Howe GR.
Department of Epidemiology, Mailman School of Public Health, Columbia
University, New York, New York 10032, USA. lbz7 at columbia.edu

Studies of radiation-associated risks among workers chronically exposed to
low doses of radiation are important, both to estimate risks directly and to
assess the adequacy of extrapolations of risk estimates from high-dose
studies. This paper presents results based on a cohort of 45,468 nuclear
power industry workers from the Canadian National Dose Registry monitored
for more than 1 year for chronic low-dose whole-body ionizing radiation
exposures sometime between 1957 and 1994 (mean duration of monitoring = 7.4
years, mean cumulative equivalent dose = 13.5 mSv). The excess relative
risks for leukemia [excluding chronic lymphocytic leukemia (CLL)] and for
all solid cancers were 52.5 [95% confidence interval (CI): 0.205, 291] and
2.80 (95% CI: -0.038, 7.13) per sievert, respectively, both associations
having P values close to 0.05. Relative risks by dose categories increased
monotonically for leukemia excluding CLL but were less consistent for all
solid cancers combined. Although the point estimates are higher than those
found in other studies of whole-body irradiation, the difference could well
be due to chance. Further follow-up of this cohort or the combination of
results from multiple worker studies will produce more stable estimates and
thus complement the risk estimates from higher-dose studies.
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.....whose findings have been summarised by others in the graph (image) I
posted at
http://www.cns-snc.ca/branches/quebec/reactions/Zablotska_2004e_sml.gif

.....obviously, the cancer risk for the ARWs is low -- but presumably it
will catch up with the general population, as the group ages.

Comments welcome !

 Jaro



 Jaro Franta, P.Eng.
Tel.: (514) 875-3444
Montréal, Québec
frantaj at aecl.ca
web master, CNS Québec branch:
http://www.cns-snc.ca/branches/quebec/quebec.html

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