Cohen derived LNT formula

["Field, R. William" <bill-field@UIOWA.EDU>]

Dr. Cohen,


I am sorry you do not understand my point below.  However, I think

this one concern is a critical point to understand.  I have

explained this many times since 1998.  I too have other

commitments.  But, I am respectfully trying to expedite our dialogue

beyond what we could hope to accomplish in the protracted give and take

in a journal.   After all, you have requested the dialogue on

the validity of your ecologic findings to test the LNT.  I am just

trying to get a straight response to the post below.   You have not

responded to the few specific points I raised below.  

Regarding your request for me to write a letter to the editor.  We

already wrote a Forum paper, a Rejoinder and a follow-up letter (

http://www.lww.com/health_physics/0017-90789-99ltrs.html)

discussing your test of the LNT.  I read your responses and failed

to find where you specifically answered many of our concerns including

the problem I noted below with your study.  Could you take just a

few minutes and specifically address my concern below.  However, if

you truly believe the BEIR formula is not general enough to allow for any

degree of control for smoking, including factors such as pack-year rate

and duration of smoking in addition to even non linear effects of smoking

please let me know since that creates a problematic road block for moving

ahead.  I think we are in agreement the formula you derived is not

able to treat both smoking duration and intensity.  Your response

below circumvents the specific points I made below.


Let me try one more time.  Your LNT derived formula does not allow

for treatment of smoking intensity and duration as the BEIR formula

does.  If your LNT formula, a priori, does not allow you to treat

smoking duration and intensity, how can you after the fact try to correct

the cross-level bias by using county averaged data. You already

previously indicated you can only "crudely" attempt to estimate

pack-year rate and have never addressed duration of smoking.


Respectfully. Bill Field



At 10:30 AM 2/21/2002 -0500, BERNARD L COHEN wrote:

        --I don't understand what you are saying, and you raise so many
points that it would take a lot of time to address each one, and I am very
short of time. If you could point to something you object to in any of my
papers, I will respond. Better yet, send a letter to the Editor and that
would justify the time it would take me to respond.
        If you don't think I used the BEIR-IV formula, or if you don't
agree with my mathematical development of it to do what I did, please
specify very specifically what your objections are. Most of your
criticisms are too general. Be very specific.

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


On Wed, 20 Feb 2002, R. William Field wrote:

> Field wrote: I addressed a very specific problem below with your study.  You  state that a basic theory takes into account, "the most important things."   I consider smoking intensity and duration two of the most important parameters to
> consider in validating your derived LNT formula.
>
> Dr. Cohen wrote: I am testing the BEIR formulas, and they do not include these things
>
> Field response:
>
> Dr. Cohen, the BEIR formulas DO indeed include "these things".  As we
> explained many years ago, HPJ 75(1), July 1998, page 13.    The BEIR model
> is quite general and allows for any degree of control for smoking.  You can
> include factors such as pack-year rate and duration of smoking in addition
> to even non linear effects of smoking.  As was pointed out in BEIR IV, "The
> choice of an appropriate age specific background rate for this calculation
> involves proper treatment of smoking, sex, and calendar time."
>
> Your previous response was that you "crudely" treat pack-year rate.  But
> your crude treatment is  after the cross-level bias already occurred.  My
> point which you have ignored for years is that you have not derived an
> equivalent BEIR model.  You can not assume smoking intensity and duration,
> are not important factors to include in your LNT derived formula.  Then
> latter try to treat the problem of smoking intensity and duration by using
> aggregate data.  You are not really testing the LNT using your formula.
> Your findings do not convince me the LNT fails, I am only convinced that
> your formula is not robust enough to test the LNT.  It is not surprising, as
> Dr. Gilbert pointed out, that that your results are confounded by smoking,
> because other smoking  related cancers are also negatively associated with
> your county radon data.
>
> Bill Field
>
>
>

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