Re: Cohen's questions

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

On Fri, 27 Jun 2003 epirad@mchsi.com wrote:



> Dr. Cohen, You wrote that to your knowledge, there have been no publications

> contesting your data.

>

> You either have not read or have forgotten these papers to name a few:

>

> Field RW, Smith BJ, Lynch CF. Cohen's paradox. Health Physics. 77(3): 328-9,

> Sep 1999.

>

> Smith B J;Field R W;Lynch C F. Residential 222Rn exposure and lung cancer:

> testing the linear no-threshold theory with ecologic data. Health Physics. 75

> (1): 11-7, Jul 1998.

>

> Field, R.W., Smith, B.J. and Lynch, C.F.. Ecologic Bias Revisited, A Rejoinder

> to Cohen’s Response to Residential radon-222 exposure and lung cancer: testing

> the linear no-threshold theory with ecologic data. Health Physics. 75(1): 31-

> 33, 1998.



	--I meant no papers other than yours

>

> In fact, Dr. Puskin referenced one of these papers pointing out his concern

> with some of your smoking data, which was further reinforced by his finding.



	--I thought we were discussing lung cancer and radon data. Puskin

(and Gilbert) have suggested that there may be something wrong with my

smoking data, but did not criticize the way it was derived. I showed that

errors in my smoking data cannot affect the results of my studies (see

item #15 on my web site).



> ----------------------------

> Dr. Cohenn stated, My lung cancer data are from National Center for Health

>  Statistics. If those data are no good, why are they collected?

>

> In part they are collected because of ease of collection.



	--I would bet they cost millions of dollars per year to collect,



> They were never

> intended for use to test the LNT or to use to "treat" confounding. However, my

> point was that the SEER data is more reliable and it is in very poor agreement

> with the data you use.



	--I suppose that anyone who believes that the data from NCHS are

no good and that the errors they contain are very highly correlated with

radon levels, they need not accept my results. I do not believe that use

of SEER data would change my results substantially, and will go to the

great effort of feeding that data into my data bases if I can be given

some reason to believe the resulting analysis would be publishable



> Consider this finding:

>

> Arch Intern Med. 2001 Jan 22;161(2):277-84.

>

> Problems with proper completion and accuracy of the cause-of-death statement.



> What is your response to this study?



	--This is outside my area ef expertise.

> -----

> Dr. Cohen states that, the issue of measuring radon now to explain lung cancers

> presumably due to radon exposures many years ago is present also in essentially

> all case-control studies.

>

> Please understand that non differential radon exposure misclassification in a

> case-control study lowers the risk estimates to no association, but in an

> ecologic study can produce unbounded bias in a negative or positive direction.



	--This is a highly theoretical statement, with no consideration of

plausibility. I need a concrete example.



> Dr. Cohen states, "My very extensive studies have shown that nothing except

> urban-rural differences correlate strongly with radon".

>

> Perhaps you need to more concerned with what correlates with smoking such as

> urban/rural differences since that is driving the majority of the risk versus

> effect.



	--That is the problem I have treated. See, for example, Sec.L of

item #1 on my web site.



  I presented a potential way for you to perform the analyses to test

> the plausibility of my suggestion (using a Monte Carlo Analyses or a

> Sensitivity Analyses), now the rest is up to you.



	--I cannot undertake large projects just to satisfy you. If they

are practcal to do and publishable, I will undertake them. In my mind, my

treatments have covered any problems that I can understand. If there are

problems I do not understand, I ask that they be stated in terms of

concrete hypothetical examples -- those I can understand.



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