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Re: Another (partial) literature review (radon)
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
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