RE: Risks of low level radiation - New Scientist Article

["Jim Nelson" <nelsonjima@HOTMAIL.COM>]

PLEASE REPLY OFF LIST>



>From: BERNARD L COHEN <blc+@pitt.edu>

>To: Jim Nelson <nelsonjima@hotmail.com>

>CC: jim.dukelow@PNL.GOV, hflong@pacbell.net, radsafe@list.vanderbilt.edu

>Subject: RE: Risks of low level radiation - New Scientist Article

>Date: Fri, 07 Dec 2001 12:34:31 -0500 (EST)

>

>

>On Fri, 7 Dec 2001, Jim Nelson wrote:

>

> > I diasagree totally with what you wrote below. What you are saying below 

>is

> > that smoking is not an important factor for lung cancer.

>

>	--I said nothing of the kind. I said that if all counties studied

>had very nearly the same smoking prevalence, the variations in the data

>due to these very small differences in smoking would be very small.

>

>  You really think

> > "ethnic variations, medical services, reporting variations, chemicals in 

>the

> > environment and in the food,respiratory illness, etc, and just plain

> > statistical variations" cause prclude a good correlation between smoking 

>and

> > lung cancer for the counties?

>

>	--No. They do not interfere with the correlation. But they still

>cause variations in cancer rates which are larger than those caused by

>smoking differences because the smoking differences are very small. Hence,

>they lead to a very small R-squared

>

>   The number of standard deviations are not

> > important.

>

>	--They are a direct measure of how lung cancer rates depend on

>smoking. What else is important?

>

>   What is important is that the smoking rates for counties are

> > actually predictive of the lung cancer rates for those counties.

>

>	--If the smoking prevalence for all counties is nearly the same,

>other small factors that differ much more would dominate the variations in

>lung cancer.

>

>

>  I also note there is a huge unexplained inverse

> > relationship between your radon measurments and the smoking rates for 

>the

> > counties.  While I would like to know the reason for this inverse 

>relation,

> > it is obvious that by not using good smoking exposure data, you are left

> > wwith residual condfounding from smoking to explain your finding.

>

>	--The inverse correlation between smoking and radon is easily

>explainable, but that is irrelevant. That inverse correlation reduces the

>discrepancy between my data and LNT predictions. If there were no

>correlation between radon and smoking, the discrepancy I found would be

>still larger.

>





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