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Radon
I do not think the IA study followed the 150 Bq m-3 over and under
stratification. Didn't they use equal exposure categories and then let the
subjects fall within them?
Les
>From: Tom Mohaupt <tom.mohaupt@wright.edu>
>To: Les Crable <lescrable@hotmail.com>
>CC: bcradsafers@hotmail.com, radsafe@list.vanderbilt.edu
>Subject: Re: Another (partial) literature review (radon)
>Date: Mon, 14 Jan 2002 16:42:42 -0500
>
>Les,
>At present the radon data in residential levels is very blurry. Some
>studies include a confounding factor that has an OR that is more than a
>magnitude higher. Some studies exclude intercomparing low order risk
>factors for lung cancer. It seems to be "vogue" now to stratify data to
>obtain a category of ">140 Bq/m^3". No one has ever shown that the action
>levels used by most industrial nations (i.e., 200 Bq/m^3 for new
>construction and 400 Bq/m^3 for old buildings) are inappropriate and less
>safe. Using the EPA action level as the cut off might lead one to believe
>that the studies are performed more for political reasons than to add
>clarity to any relationship radon concentration may have with lung cancer.
>Also. by setting the highest radon group at ">140 Bq/m^3" the investigators
>are excluding any evaluation of the data at radon action levels accepted
>internationally. Why?
>
>Take a look at the ranges included in the radon categories:
>0-50 Bq/m^3 includes 50 Bq/m^3
>50-80 Bq/m^3 includes 30 Bq/m^3
>80-140 Bq/m^3 includes 60 Bq/m^3
> >140 Bq/m^3 covers nearly an infinity of values
>
>How about stratifications that are more equally distributed, such as 0-100,
>100-200, 200-400, 400-800, 800-1200, 1200 and above. Of course the answer
>is because about 1/2 the cases and controls have radon levels below 50
>Bq/m^3 and about 80% of the cases and controls have radon levels below 140
>Bq/m^3.
>As a minimum, I would like to see the last category regrouped to evaluate
>200 and 400 Bq/m^3. Wouldn't you?
>
>Tom
>Les Crable wrote:
> >
> > Tom,
> >
> > Why is this a bias? They were likey setting exposure categories so that
> > their results could be comparable with som of the U.S. studies.
> >
> > >From: "Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>
> > >Reply-To: "Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>
> > >To: radsafe@list.vanderbilt.edu
> > >Subject: Re: Another (partial) literature review (radon)
> > >Date: Mon, 14 Jan 2002 16:27:02 +0000
> > >
> > >Thank you! A better way to stratify the data may be to randomize the
> > >intervals and use some average to get away from this kind of bias. The
>same
> > >problem seems to be true for some power line/leukemia studies.
> > >
> > >Bjorn Cedervall bcradsafers@hotmail.com
> > >------------------------------------------
> > >>The radon action levels in most of Europe is 200 Bq/m^3 for new
> > >>construction and 400 Bq/m^3 for old houses. The authors stratified the
> > >>data
> > >>for (values in Bq/m^3) <50, 50-100, 101-200, 201-400, >400. But their
>data
> > >analysis used grouping of (values in Bq/m^3): <50, 50-80, 80-140, and
> >140,
> > >which coincides with the U.S. EPA levels. I found this change curious.
> > >The authors report a RR of 1.55 for >140 Bq/m^3.
> > >
> > >The European classification is still positive, but the number of cases
>is
> > >low enough to change the results significantly with a single addition
>or
> > >deletion of a case in any group above 200 Bq/m^3.
> > >RR (measured results) for 101-200: 1.15, 201-400: 1.15, >400: 1.20
> > >
> > >
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>--
>Thomas Mohaupt, M.S., CHP
>University Radiation Safety Officer
>
>104 Health Sciences Bldg
>Wright State University
>Dayton, Ohio 45435
>tom.mohaupt@wright.edu
>(937) 775-2169
>(937) 775-3761 (fax)
>
>"An investment in knowledge gains the best interest." Ben Franklin
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