AW: [ RadSafe ] Nuclear mortality
garyi at trinityphysics.com
garyi at trinityphysics.com
Wed Aug 6 09:26:48 CDT 2008
I wonder how different this statistical wish fullfilment is from that popcorn link that was posted
the other day. I followed the popcorn link and watched the clip. Later I thought how sad it
was that so many people accept such things at face value. Now I feel like King David when
Nathan says to him "You are the man!"
There are simply too many ideas being thrust upon us these days. We have enough time
and resources to really validate only a few of them, so it is inevitable that we will be wrong
about some things that seem quite true to us.
Well, maybe ignorance really is bliss. :)
-Gary Isenhower
On 6 Aug 2008 at 14:23, Rainer.Facius at dlr.de wrote:
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Ross,
thank you for this important reference:
Atkinson W D, Law D V, Bromley K J.
A decline in mortality from prostate cancer in the UK Atomic Energy
Authority workforce J Radiol Prot 27#4(2007)437-445
The last sentence of their abstract merits singular recognition.
"Our conclusion is that the original observation might have been a
chance finding among many significance tests."
In the statistical literature this perennial and pervasive predicament
of many radio epidemiological studies is called the "multiple testing"
problem, which unfortunately has not yet found a universally
reasonable solution.
Applying the 'zero order' solution of Bonferroni by dividing type I
error probabilities (e.g. 5%) by the number of tissues/organs tested
would discard all (putative statistically significant) associations
ever reported of cancer incidence/mortality with low dose occupational
radiation exposures as statistical noise - even where one-sided tests
(which already postulate a negative association) were applied and even
if only an unusual low confidence level of only 90% would be
stipulated. The latter two tricks, which facilitate the detection of
statistically 'significant' associations, are not uncommon in radio
epidemiological studies. (Honni soi qui mal y pense).
For me, their paper corroborates another personal 'bias' or
long-standing suspicion.
The know refuted earlier statistically significant associations of
prostate cancer with radiation exposure came from case-control (or
nested case-control) studies of the UKAEA workforce. I.e., one part of
the study population is selected by the very fact of having contracted
the disease under study. A frequent observation with such case-control
studies is that whenever the same or a comparable population is
studied in a cohort study, the significant associations found in the
case-control study evaporate. Here once more Atkinson et al. report
such an instance.
In principle, if properly done, both study designs should yield -
within statistical uncertainty - the same results. In practice,
therefore, it appears to me that - ceteris paribus - it must be much
more difficult to account properly for possible pitfalls in case of
case-control studies than it is in cohort studies. This may be the
reason why in the "levels of evidence" of the Oxford Centre for
Evidence-based Medicine results from cohort studies always rank above
case-control studies.
Based on (only) a case-control study are also the findings on prostate
cancer after diagnostic radiation exposures recently advertised in
radsafe (Otto Raabe, Do 31.07.2008 20:30).
P Myles P, Evans S, Lophatananon A, Dimitropoulou P, Easton D, Key T,
Pocock R, Dearnaley D, Guy M, Edwards S, O'Brien L, Gehr-Swain B, Hall
A, Wilkinson R, Eeles R, Muir K. Diagnostic radiation procedures and
risk of prostate cancer. British Journal of Cancer 98(2008)1852-1856
The authors carefully stop short of claiming a causal relation behind
the association they found (although they somewhat uncritically quoted
from papers which do exactly this).
Finally, to my knowledge all studies yielding a statistically
significant association between lung cancer and exposure to domestic
radon are case-control studies again.
My personal bias, as I readily admit it to be, is once more
intensified by Atkison et al.:
Beware of conclusions based on case-control studies only.
Regards, Rainer
Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
GERMANY
Voice: +49 2203 601 3147 or 3150
FAX: +49 2203 61970
-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im
Auftrag von Ross Beveridge Gesendet: Mittwoch, 6. August 2008 02:01
An: 'Steven Dapra'; radsafe at radlab.nl; 'Joel Cehn' Betreff: RE: [
RadSafe ] Nuclear mortality
The Journal of Radiological Protection, Volume 27, Number 4, December
2007 carries a article titled 'A decline in mortality from prostrate
cancer in the UK Atomic Energy Authority workforce'.
Whilst not a study of the general mortality it may give some
information to respond with.
Regards
Ross
-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Steven Dapra Sent: 08 July 2008 21:18 To: radsafe at radlab.nl
Subject: Re: [ RadSafe ] Nuclear mortality
July 8
I did a Google search for "Atomic veterans" "mortality study"
and was referred to an online book by the National Academy
Press. The link below will take you to page one of the front
matter. This is the material on page one:
Mortality of Veteran Participants in the CROSSROADS Nuclear Test
Medical Follow-up Agency INSTITUTE OF MEDICINE by J. Christopher
Johnson Susan Thaul William F. Page Harriet Crawford with oversight
from the Institute of Medicine Committee on the CROSSROADS Nuclear
Test NATIONAL ACADEMY PRESS Washington, D.C. 1996
http://books.nap.edu/openbook.php?record_id=5428&page=R1
I would recommend reading the Summary, the Study Rationale,
and Other Studies of the Human Health Effects of Radiation
Exposure. Of course, this is only about the CROSSROADS test,
however it should get you started.
The first Reference is to Beebe GW and Simon AH. Ascertainment of
mortality in the U.S. veteran population. American Journal of
Epidemiology 89:636---643, 1969; which will doubtless give a broader
picture.
Steven Dapra
At 02:07 PM 7/8/08 -0400, Joel Cehn wrote:
>Regarding "Numerous medical studies in the last 50 years clearly
>establish that when large populations are exposed to..."? is anyone
>aware of a mortality study of "atomic veterans?"? I was asked about
>that the other day.
>
>
>Joel I. Cehn, CHP
>Oakland, California
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