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

[Rainer.Facius at dlr.de]

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 
> that value at best can serve as a rationale to spend money on a 
> repetition of a study.
> 
> 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: radsafe-bounces at radlab.nl
> [mailto:radsafe-bounces at radlab.nl] Im Auftrag von John Jacobus
> Gesendet: Freitag, 12. Januar 2007 16:16
> An: radsafe
> Cc: Rad Science List
> Betreff: [ RadSafe ] Re: Exposed "had lower incidences of all cancers 
> - "Environmental -
> 
> Dr. Long,
> Again, another typical example of cherry-picking data.
> 
> As noted in Table III
> Leukemia (all-types) Observed 7; Expected 3.3
> Malignant Lymphoma   Observed 5; Expected 1.6
> 
> If you are unable to read the article, how can one expect to have an 
> intelligent discussion with you?
> 
> Why do you constantly quote the incomplete data of Chen, et.al. of 
> 2004?
> 
> --- howard long <hflong at pacbell.net> wrote:
> 
> > John Jacobus, the paper you refer to did, indeed,
> mislead in its
> > "Conclusion", comparing its tables and discussion.
> >   HPs can judge for themselves:
> >   "Correspndence: Dr W Peter Chang, Inst. of
> Environmental Health
> > Sciences, National Y U Med School 155, sec2 Linong
> St. Taipei112,
> > Taiwan"
> >    
> >   Int.J. Radiat. Biol, Vol82, No.12, Dec. 2006 pp
> > 849-858
> >   (The Environmental Health Sciences  review by
> Chang et al of  cancer
> > risks in 7,271 persons exposed to 1 to 2,363 mSv
> gamma over 23 years),
> >   "ABSTRACT
> >   Conclusion [ in entirety],
> >    The results suggest that prolonged low dose
> radiation exposure
> > appeared to increase risks of developing certain
> cancers in specific
> > subgroups  of this population in Taiwan."
> >    
> >    "Received 12 May 2005; revised 11 Sept. 2006;
> accepted 18 Oct. 
> > 2006".
> >    
> >   The opposite impression, much cancer was
> prevented by the radiation,
> > is clear from its
> >    
> >   Table III "All cancers - Observed  95 Expected
> > 114.9 "
> >               "Solid cancers - Observed 82
> Expected 109.5" and
> >   "Discussion: - Compared to the reference
> population, the study
> > population had lower incidences of all cancers
> combined, all cancers
> > combined except leukemia and all solid cancers
> combined (Table III)."
> >    
> >  

+++++++++++++++++++
"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


 
____________________________________________________________________________________
Do you Yahoo!?
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com