[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Cohen's Refutation of LNT
You said wrt Colditz and Cohen's data:
> He would say the ecologic study was good to form hypotheses, but the
> hypotheses have been proven wrong by the more rigorous case-control
studies.
My question was: What formal hypothesis was ever formulated from Cohen's (or
EPA) data and what case-control study has tested (never mind proved wrong)
such a hypothesis?
Kai
----- Original Message -----
From: "Rad health" <healthrad@hotmail.com>
To: <info@eic.nu>; <bill-field@uiowa.edu>
Cc: <radsafe@list.vanderbilt.edu>
Sent: Sunday, February 10, 2002 4:14 PM
Subject: Re: Cohen's Refutation of LNT
> An hypothesis does not have to be a risk model. Most of the residential
> radon studies' hypotheses were that there is increased lung cancer with
> increased radon exposure. I don't think anyone set out in their
hypotheses
> whether to test the shape of the dose response curve. Maybe the pooling
> studies are doing that?
>
> The Iowa study showed how a case-control study can show different results
> than an ecologic study. This has been shown by others also.
>
> I think the hypotheses the Iowa Study choose to explore, since their
> experimental objectives included smokers, was does radon have a
> statistically significant dose response in those people who have developed
> lung cancer. I think Dr. Field already said they were going to look at
the
> non smokers in the pooled analyses.
>
> >From: Kai Kaletsch <info@eic.nu>
> >To: field <bill-field@uiowa.edu>, Rad health <healthrad@HOTMAIL.COM>
> >CC: radsafe@list.vanderbilt.edu
> >Subject: Re: Cohen's Refutation of LNT
> >Date: Sun, 10 Feb 2002 13:54:28 -0600
> >
> >Sorry, what I meant to ask was if anyone had formulated an individual
risk
> >model (hypothesis) based on the US data (Cohen's or EPA ...)
> >
> >Thanks for the reference below. For a specific question about that paper:
> >
> >What was the hypothesis that was generated from the fact that "Within low
> >smoking
> > counties, rates for all lung cancer and small cell carcinoma were
> > significantly lower (p < 0.05) in the high radon counties relative to
the
> > medium and low radon counties." and how was it tested in the later Iowa
> >study?
> >
> >An obvious hypothesis (but not the only possible one) would be: "In low
> >concentrations, radon can prevent the occurrence of lung cancers in
> >non-smokers."
> >
> >To test this hypothesis with a case control study, you would limit the
> >study
> >to non-smokers, because your hypothesis only deals with non-smokers. You
> >would also have to choose your exposure categories so that an increased
> >risk
> >in "low" exposed individuals could be detected. That would probably mean
> >limiting your study to low radon, low smoking counties. (After all, you
are
> >trying to figure out what is killing the people in these counties.)
> >
> >The obvious problem with a study like this is the small sample size.
> >However, including individuals or populations (e.g. smokers) that are not
> >relevant to your hypothesis actually makes the statistics worse.
> >
> >Science should go like this:
> >
> >1. You make an observation. (via ecological study or whatever.)
> >2. You come up with a formal, preferably quantitative, hypothesis to
> >explain your observation.
> >3. You crunch the numbers to ensure that your hypothesis could
actually
> >explain your observation. If it can't, go back to step 2.
> >4. You design an experiment (case-control study or whatever) to test
> >your
> >hypothesis.
> >5. You clearly state the hypothesis to be tested and how the
particular
> >experiment will confirm or refute the hypothesis.
> >6. You perform the experiment and present the results.
> >7. You show how the results of the experiment either confirm or refute
> >the hypothesis.
> >8. If your experiment refutes the hypothesis, go back to step 2.
> >
> >All I can see are steps 1 and 6.
> >
> >Regards,
> >Kai
> >
> >----- Original Message -----
> >From: "field" <bill-field@uiowa.edu>
> >To: "Kai Kaletsch" <info@eic.nu>; "Rad health" <healthrad@HOTMAIL.COM>
> >Cc: <radsafe@list.vanderbilt.edu>
> >Sent: Sunday, February 10, 2002 12:10 PM
> >Subject: Re: Cohen's Refutation of LNT
> >
> >
> > > Kai,
> > >
> > > We published an ecologic study very early on before we followed up
with
> >a
> > > case control study.
> > >
> > > : Health Phys 1994 Mar;66(3):263-9 Related Articles, Books, LinkOut
> > >
> > >
> > > Residential radon exposure and lung cancer: evidence of an urban
factor
> >in
> > > Iowa.
> > >
> > > Neuberger JS, Lynch CF, Kross BC, Field RW, Woolson RF.
> > >
> > > Department of Preventive Medicine, University of Kansas School of
> >Medicine,
> > > Kansas City 66160-7313.
> > >
> > > An ecological study of lung cancer, cigarette smoking, and radon
> >exposure
> > > was conducted in 20 Iowa counties. County-based lung cancer incidence
> >data
> > > for white female residents of Iowa were stratified according to radon
> >level
> > > and smoking status. Cancer incidence data for the period 1973-1990
were
> > > obtained from the State Health Registry of Iowa. Smoking level was
> > > determined from a randomly mailed survey. Radon level was determined
> > > according to an EPA supported charcoal canister survey. Within low
> >smoking
> > > counties, rates for all lung cancer and small cell carcinoma were
> > > significantly lower (p < 0.05) in the high radon counties relative to
> >the
> > > medium and low radon counties. However, within high smoking counties,
> >rates
> > > for all lung cancer, adenocarcinoma, and small cell carcinoma were
> > > significantly higher (p < 0.05) in the high radon counties relative to
> >the
> > > low radon counties. Variations in socioeconomic data for these
counties,
> > > available through the 1980 and 1990 census, did not explain these
> >results.
> > > Lung cancer rates also were significantly increased in urban counties
> >even
> > > after holding smoking status constant. Multivariate analyses revealed
> > > significant interactions between smoking, urbanization, radon levels,
> >and
> > > lung cancer. The results of this hypothesis generating study will be
> >tested
> > > in a case/control study now ongoing in Iowa. Analysis will need to
> >include
> > > separate evaluations by smoking status, radon level, and residence in
> >urban
> > > or rural areas for the major morphologic types of lung cancer.
> > >
> > > Regards, Bill
> > >
> > > ----- Original Message -----
> > > From: Kai Kaletsch <info@eic.nu>
> > > To: Rad health <healthrad@HOTMAIL.COM>
> > > Cc: <radsafe@list.vanderbilt.edu>
> > > Sent: Sunday, February 10, 2002 10:51 AM
> > > Subject: Re: Cohen's Refutation of LNT
> > >
> > >
> > > > > He would say the ecologic study was good to form hypotheses, but
the
> > > > > hypotheses have been proven wrong by the more rigorous
case-control
> > > > studies.
> > > >
> > > > Could anyone please provide a reference where a hypothesis has ever
> >been
> > > > formed based on the ecological radon data? So far I have only seen
> > > > regressions of the COUNTY risk. I am not aware of a single
INDIVIDUAL
> >risk
> > > > model that has been constructed to explain the county data.
> > > >
> > > > Could anyone please provide a reference where such a hypothesis has
> >been
> > > > tested by a case control study. The studys I have seen simply find
> >risk
> > > > coefficients for a linear model. Would anyone really hypothesise a
> >linear
> > > > individual risk model by looking at the county data?
> > > >
> > > > Thanks,
> > > >
> > > > Kai
> > > >
> > > >
> > > >
> >************************************************************************
> > > > You are currently subscribed to the Radsafe mailing list. To
> >unsubscribe,
> > > > send an e-mail to Majordomo@list.vanderbilt.edu Put the text
> >"unsubscribe
> > > > radsafe" (no quote marks) in the body of the e-mail, with no subject
> >line.
> > > You can view the Radsafe archives at
http://www.vanderbilt.edu/radsafe/
> > >
> >
>
>
> _________________________________________________________________
> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>
************************************************************************
You are currently subscribed to the Radsafe mailing list. To unsubscribe,
send an e-mail to Majordomo@list.vanderbilt.edu Put the text "unsubscribe
radsafe" (no quote marks) in the body of the e-mail, with no subject line. You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/