Re: Mossman paper in Health Physics News - The Debate is Over

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

On Fri, 6 Jun 2003 epirad@mchsi.com wrote:



> In the previous email I pointed out that - your smoking data is co-correlated

> with socioeconomic status, poor health care, apartment living, mobility, lower

> education status, etc.  You have never assessed all these variables in a

> multivariate analyses.  And in fact, this would be impossible to adequately

> because of the non linear relationships between these factors within and

> between counties.



	--The basic equation for my study is the following relationship

between lung cancer rates corrected for smoking prevalence, M, and radon

exposure, r, for U.S. counties:

	M = A + B r

where A is close to 1.0 and according to LNT, B =+7.3 (in percent

per/pCi/L)> If you do not agree to this, that is another issue.

	The issue you raise here is that there may be confounding factors

that correlate strongly, for unrelated reasons, with M and with r. As an

example, there may be pollutants X, Y, and Z that correlate with M because

they cause lung cancer or because they stimulate the desire to smoke. For

some unrecognized reason, they may scavenge radon out of the air in homes.

Thus, counties with high levels of these pollutants would tend to have

high lung cancer and low radon levels, and vice versa. Am I correct in

assuming that is what you mean?

	This issue is addressed in Item #7 on my web site, in Section 3,

where it is shown that the existence of confounding factors with the

required correlations with both M and r is extremely implausible. If you

read and understand the treatments in that section and have reservations

about them, please let me know so we can discuss them. If you do not

understand them, please ask for explanations on specific points. If you

would like to offer a different example, please do. The examples you

mention above are all related to socioeconomic factors that I have

investigated thoroughly in my paper "Updates and Extensions to Tests of

LNT", Technology 7:657-672;2000.

	Contrary to what you state above, in my treatments, I do not

assume linear behavior of confounding factors with radon, lung cancer

causation, or smoking, I use multivatiate regression only with great

caution for that reason, and for others explained in Section 2.2 of item

#7 on my web site.



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