Re: LNT models -Constancy of Radon levels over time??

[Bernard L Cohen <blc+@pitt.edu>]

On Wed, 8 Mar 2000, Tom Mohaupt wrote:

> Stewart raises an interesting point. Radon is not constant. The
> concentration has been changing over the years due to buttoning up homes
> and filtering air. He suggests these changes could impact Dr. Cohen's
> findings. This point can easily applied to residential radon studies done
> up to date. It also applies to the Iowa study, which does not correct for
> this effect. See "Residential Radon and Lung Cancer Case-Control Study" at
> http://www.cheec.uiowa.edu/misc/radon.html. The paper describes the Iowa
> radon study methodology for those of you who are interested.
> Tom

	--My paper in HEALTH PHYSICS 60:631-642 presents elaborate
studies of radon levels vs age of houses, and the differences are not
large. It also includes a study of houses whose answer to the question
"How much has been done since 1975 to reduce heat loss from your house by
weatherstripping, closing gaps under doors, sealing windows, etc" were
"Much", "little", or "nothing". The relative radon levels corresponding to
these answers were:     much - 1.02; little - 0.92; nothing - 1.00. (Note
that 1975 was when the drive to reduce enrgy consumption began, following
the Energy crisis").
        These studies involved tens of thousands of houses from every
section of the nation, and results were similar for all sections.
        I might point out that these problems are much more likely to
cause trouble in case-control studies. It is much more likely that there
was a change in a particular house than in the county average.
        I might also point out that, for these problems to affect my test
of LNT, they would have to be different for different counties in a way
that correlates very strongly with radon levels. I have studied over 500
factors that might potentially confound the lung cancer vs radon
relationship, and none of them correlates strongly enough with radon
to make a difference in my analyses.

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu



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