Re: Cohen's erroneous statements

[BERNARD L COHEN <blc+@PITT.EDU>]

On Fri, 11 Jan 2002, Rad health wrote:



> BERNARD L COHEN wrote on Fri, 11 Jan 2002 09:40:36 -0500 (EST)wrote:

>

> BC  Note that your suggestion would also affect every other study that

> has ever been done on radon vs lung cancer, including all the case-control

> studies.

>

> Dr. Cohen's statement is incorrect - The MO study used glass-based detectors

> which can estimate past radon progeny exposure. Further- the Iowa study used

> HRD detectors which can examine the degree of progeny attachment and

> retrospective radon progeny exposure



	--Can you remind me of the references where these detectors are

described? I will look them up, but I seriously doubt if they truly handle

the problem of equilibrium factors and unattached fraction. In any case, I

am confident that my remark applies to all the other case-control studies.



> BC Are you suggesting that a treatment is needed for non-smokers

> living in houses where there are smokers? That would be very difficult in

> any study. In case-control studies, they don't ask whether there are other

> people in the house who smoked.

>

> Again Dr. Cohen's statement is absolutely false. Most of the case-control

> studies collect this information including the IA and MO studies.



	--What do they do with that information? I don't see how they can

use it. Please explain.



> Dr. Field offered to write a paper with Dr. Cohen over a year ago to examine

> the strengths and limitations of the ecologic approach versus the

> case-control approach in evaluating the risk posed by residential radon

> exposure.  Dr. Cohen declined (check the archives).



	--I don't remember this; please let me know how to check on it. In

any case, I am not a defender of ecological studies in general; in fact I

have offered to show how any other published ecological study can give a

false conclusion. However, I have not been able to do that for my study,

and neither has anyone else. My study is very different from all other

ecological studies in that I am testing the linear-no threshold prediction

rather than trying to determine the risk vs dose relationship for

individuals, and also in that I have so many data points (1601 counties)

that I can treat confounding factors with stratification; other

differences are discussed in my papers.

	I have never dodged any attempt to explain my data, if that is

what you are implying.



 Dr. Cohen should be

> able to support the validity of his findings without relying on saying this

> is how case-control studies do it. In other words let your study stand or

> fall on its own merits.

>

	--If people accept the case-control studies and I treat some

problem the same way they do, I think they should not criticize me on that

aspect. I never rely on that as my only defense, but simply mention it in

passing.





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