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RE: Cancer deficiency clusters
Howard,
But if we question the validity of statistical cluster that show a higher
increase of cancer near a power plant, it should be, and is, statistically
probable that studies will show a statistical cluster of healthful effects
of radiation.
You noted the Nuclear Shipyard Worker Study. It you like, I will send a
copy of the abstract written by one of the authors of the study, Dr.
Genevieve Matanoski. It appeared in Radiation Research 133, 126-127 (1993).
(I think it is important to supply references rather than speculations,
don't you?) Quoting the abstract:
"The data clearly indicate that both nuclear worker groups have a lower
mortality from leukemia and lymphatic and hematopoietic cancers than does
the nonnuclear group. All three groups have lower rates than the general
population. However, if the NW<5.0 or the 5.0-9.0 mSv group is used for
comparison, than all dose groups 10 mSv and above in the NW>/= 5.0 group
have higher mortality rates that the NW<5.0 group for both leukemia and all
lymphatic hematopoietic neoplasms. There is no consistent dose response
with radiation, which would suggest that radiation is not the factor
associated with the increase. . . . The SMRs are very sensitive to any
changes, such as lagging, due to small numbers, so these within-group
observations may simply represent chance variations."
A couple of simplistic observations, since I am not an epidemiologist but
feel that I can understand the basics. First, this is a cohort study, which
may not have any relevance to public exposures. I guess that if you want to
reduce your risk of cancer, you should work in Naval shipyard, since "All
three groups have lower rates than the general population." Second, the
risk mortality increases at occupational exposures above 10 mSv. Third,
other factors that were not considered, such as asbestos exposures, may
influence the results as they may be more important than the factor,
radiation, that is being studied. For example, the study indicates that the
mortality from lung cancer for all groups was higher than that of the
general population. But only the non-nuclear workers had a statistically
significant increase. I guess you can conclude that radiation reduces the
risk of lung cancer in this cohort. Of course, I would rather a more
qualified epidemiologist than I review the data. While I admire John
Cameron for his work, he is not an epidemiologist either.
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
E-mail: jenday1@email.msn.com (H)
-----Original Message-----
From: hflong@postoffice.pacbell.net
[mailto:hflong@postoffice.pacbell.net]
Sent: Friday, July 19, 2002 7:03 AM
To: jjcohen
Cc: Gibbs, S Julian; Jacobus, John (OD/ORS); Radsafe Mail list
Subject: Re: Cancer deficiency clusters
Yes, Jerry,
Such a study has been done on 27,872 nuclear shipyard workers - but until
recently only reported as not showing expected increase in cancer.
John Cameron, one of 8 members of the technical advisory committee of the
Nuclear Shipyard Workers Study reports, "The cancer death rate of the NW>0.5
group [those receiving an extra 0.5 rem] was over 4 std.dev. lower than the
NNW control group [non-nuclear workers of similar ages and jobs]. This good
news is not mentioned but the data are available in the final report."
http://www.aps.org/units/fps/oct01/a5oct01.html
. . .
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