AW: AW: AW: [ RadSafe ] Re: Exposed "had lower incidences of allcancers - "Environmental -

[John Jacobus]

Rainer,
I am sorry, but what selection do you think I made.  I
did not say that the leukemia values were significant.
 Nevertheless, they should be noted.  Are you saying
that only reduction in total cancers are significant? 
It appears to me that neither set of numbers are
startling.  As you mentioned, differences of 2 to 3
times the normal incident rates are, and I agree with
that.  The small values of incident increases or
deceases should be viewed the same.  They are small
number.  Again, I do not think that people should
cherry-pick the data from a report without also citing
factors that may contradict.

Low doses of radiation delivered at low dose rates
certainly do not increase cancer or adverse risks.  I
figured that our many years ago.  I cite the RERF data
as it does demonstrate radiation risk, but it does
have its limitations and interpretation, e.g., doses
are acute.

Yes, we both agree on the need to continue the RERF
studies, and I would suggest adding the Tiawanese
study.   I have seen very few "background" studies
that have demonstated any significant results.  


--- Rainer.Facius at dlr.de wrote:

> John, 
> 
> apparently you have forgotten that it was you who
> did the selection. It was you who asked me how I
> would interpret the reduced cancer incidences and I
> answered to this request of yours. Regarding the
> leukaemia values, you again appear to have repressed
> or forgotten my preceding demonstration that they
> were utterly (even formally) insignificant. 
> 
> Regarding my inquiry as to please provide "one or
> two studies which you consider as presenting the
> most compelling evidence that low dose and dose-rate
> exposure to low LET ionizing radiation below say 500
> mSv causes cancer" you appear to answer this by
> pointing to the RERF data as your sole basis for
> assuming that this may be so. Today you will hardly
> be able to find a radiobiologist studying low
> dose-rate effects in the laboratory at any level of
> biological organization above the molecular who
> would support the implied claim that the RERF data
> are relevant to chronic exposure of workers.
> 
> Nonetheless, I truly consider continued observation
> of the ATB survivor cohort as necessary and
> expedient.
> 
> Regarding the natural background radiation as one
> 'yardstick' to assess chronic radiation exposures we
> appear to agree. However, you appear to have not yet
> really appraised the enormous variability of this
> yardstick.
> 
> Kind regards, Rainer
> 
> 
> ________________________________
> 
> Von: radsafe-bounces at radlab.nl im Auftrag von John
> Jacobus
> Gesendet: Do 08.02.2007 18:23
> An: Facius, Rainer; radsafe at radlab.nl
> Cc: rad-sci-l at WPI.EDU
> Betreff: Re: AW: AW: [ RadSafe ] Re: Exposed "had
> lower incidences of allcancers - "Environmental - 
> 
> Rainer,
> I guess if you only look at the data selectively,
> you
> will find what you want.  You just choose to ignore
> the leukemia values and the age based incident
> rates.
> Maybe I am just more critical than you since you did
> not see the rest of the table. 
> 
> As the RERF data demonstrated, you need to follow
> this
> population for many years.  In 10 years, the
> incident
> values will be different.  Of course, if you like
> what
> you have now, why waste the money looking for more
> information.
> 
> >From what I have read, it is clear that radiation
> exposures do not present risk below 100 mSv acute
> dose. No harmful risks have also been demonstrate
> for
> fractionated and low dose rates 2 or 3 times
> background. I think that low dose experiments are
> interesting, but do not contribute much to the
> epidemiological data.  Your bet (prejudice) may be
> realized, but I doubt it.
> 
> 
> --- Rainer.Facius at dlr.de wrote:
> 
> > John,
> >
> > regarding the "reduced cancer incidences" the
> > message of table III is equally clear.
> Concentrating
> > on the pooled incidences for men and women the
> data
> > say:
> > all cancers:       95/114.9 -> SIR95%=(0.67, 0.83,
> > 1.01) : non-significant
> >
> > all w/o leukaemia: 88/111.6 -> SIR95%=(0.63, 0.79,
> > 0.97) : formally significant
> >
> > all solid cancers: 82/109.5 -> SIR95%=(0.60, 0.75,
> > 0.93) : formally significant
> >
> > In my view, for the purely statistical evaluation
> of
> > a putative beneficial association the same
> criteria
> > should be applied as for the appraisal of a
> putative
> > detrimental association, i. e., these data at best
> > can serve as a justification to continue such
> > epidemiological investigations. Hence, I would
> > hesitate to claim the above 'positive'
> associations
> > as proof for a beneficial action of those
> exposures.
> >
> >
> > However, such - by controlled, truly low dose and
> > dose-rate laboratory work - well established
> > phenomena like induced radiation resistance,
> > adaptive response, non-monotonous dose response
> > functions for several cancer related
> radiobiological
> > endpoints at all levels of biological organization
> > yield some plausibility to the assumption that
> > biological mechanisms do exist which indeed might
> > CAUSE the above association. My present bet
> > (prejudice) is that eventually the mechanisms
> behind
> > these laboratory observations will be sufficiently
> > elucidated so that the inference of a causation of
> > the statistical observations will be justified.
> >
> > Regarding the "consideration of all studies and
> not
> > just one report" I would urgently invite you to
> > quote the one or two studies which you consider as
> > presenting the most compelling evidence that low
> > dose and dose-rate exposure to low LET ionizing
> > radiation below say 500 mSv causes cancer.
> >
> > Kind 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: John Jacobus [mailto:crispy_bird at yahoo.com]
> > Gesendet: Samstag, 20. Januar 2007 17:05
> > An: Facius, Rainer; radsafe at radlab.nl
> > Cc: rad-sci-l at WPI.EDU
> > Betreff: Re: AW: [ RadSafe ] Re: Exposed "had
> lower
> > incidences of all cancers - "Environmental -
> >
> > Rainer,
> > I am aware of that interpretation about the
> > significans of the of SIR values.  That being
> said,
> > are the values for reduced cancer incidents also
> > insignificant?  Or does the relevance of the
> numbers
> > not important if you have a political view the
> > radiation is good?
> >
> > Cherry-picking data is common.  It is used by
> those
> > who are anti-radiation and who are looking for a
> > hormetic effect.  Nevertheless, one needs to
> > consider all of the studies, and not just one
> > report.
> >
> > --- Rainer.Facius at dlr.de wrote:
> >
> > > John,
> > >
> > > if you were able to properly interpret the
> numbers
> > given by you, you
> > > would not claim that they prove an increased
> > incidence, not to speak
> > > of a causal relation.
> > >
> > > The 95% SIR confidence interval for leukaemia
> (all
> > > types) is (0.85, 2.12, 4.37), i.e., utterly
> > insignificant.
> > > For malignant lymphoma it is (1.01, 3.13, 7.29),
> > i.e., essentially
> > > insignificant again.
> > >
> > > If you ask professional epidemiologists, you
> will
> > find a consensus
> > > that in order for an association to be
> considered
> > established by such
> > > studies, the confidence interval for standard
> > mortality or incidence
> > > ratios should exclude the value of three or at
> > least two, i.e., the
> > > _lower_ confidence limit should be above that
> > value. Findings below
> 
=== message truncated ===


+++++++++++++++++++
“We must face the fact that the United States is neither omnipotent or omniscient — that we are only 6 percent of the world’s population; that we cannot impose our will upon the other 94 percent of mankind; that we cannot right every wrong or reverse each adversity; and therefore there cannot be an American solution to every world problem.”
-- John F. Kennedy 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


 
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