Re: Radon and Lung Cancer: What the studies really say.

[epirad@mchsi.com]

Unlike ecologic studies, case-control studies are subject to much less cross-

level bias.  The fact remains that the few short-term screening radon 

measurements you use per county, do a very poor job assessing exposure for the 

people who developed lung cancer within those counties.    

> 

> On Fri, 20 Jun 2003 epirad@mchsi.com wrote:

> 

> > Unlike ecologic studies, case-control studies differ in that in a case control

> > study you directly measure the radon concetration in a home and with subject

> > mobility, the radon concentrations can be linked to mobility to get an 

> estimate

> > of exposure. The ecologic studies use a few short term measurments per home

> > (with a high percentage in the basement) while the case control studies use

> > year long living area measurements.  In an ecologic study exposure

> > nondifferential misclassification can cause unbounded extreme biases while in 

> a

> > case-control study nondifferential misclassification reduces the risk 

> estimate.

> 

> 	--The justification for my radon levels is spread over several of

> my papers and would not be easy to justify briefly here. The best

> references I can give are in Sec. D of Item #1 on my web site, and Ref.

> (Cohen 1992c) in that paper. Biases are discussed in the former. The

> briefest justification I can give is to say that my radon levels correlate

> strongly with those obtained by EPA and by State=sponsored measurements,

> and all three give the same results when used in my analyses.

> 

> > In a case control study, if you obtain retrospective information on radon

> > progeny, you can calculate dose.

> 

> 	--The great majority of case-control studies do not obtain retrospective

> information on radon

> 

> 	--Case-control studies have many weaknesses, some of which are

> mentioned in Sec. 6 of Item #7 on my web site.

> 



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