RE: Cohen's Ecologic Studies

[Jack_Earley@RL.GOV]

Now I see what is meant by "a gentleman and a scholar."



Jack Earley

Radiological Engineer





-----Original Message-----

From: BERNARD L COHEN [mailto:blc+@PITT.EDU]

Sent: Monday, June 10, 2002 7:50 AM

To: epirad@mchsi.com

Cc: radsafe@list.vanderbilt.edu

Subject: Re: Cohen's Ecologic Studies





	In communicating with other epidemiologists, I believe I may

better understand your problems in understanding my papers. The goal of

epidemiology is to determine the dose-response relationship for

individuals. For this one must have a variety of information on those

individuals, and cannot use ecological data, that is data for groups of

people, such as averages for counties.

	My study is NOT an epidemiological study in that definition, but

rather a test of the BEIR-IV LNT formula for risk vs dose from radon. I

use that formula to derive mathematically a relation between lung cancer

mortality rates, m, average radon exposure, r, and smoking prevalence, S.

This is a relation among ecological variables. If my test is invalid,

there must be a confounding factor, CF, that confounds the relationship

between these 3 quantities. In most cases, these CF can be represented by

ecological data, but I have identified and treated a few cases where

this is not sufficient.

	You and other epidemiologists are disturbed by the fact that I do

not treat CF on the level of individuals. But there is no logical need for

considering them unless it can be shown that they lead to confounding of

the relationship betweer m, r, and S. When you express such objections, I

ask for an example of how they can affect that relationship.

	I will be out of town for the rest of this week so will not be

reading my e-mail for a few days.



Bernard L. Cohen

Physics Dept.

University of Pittsburgh

Pittsburgh, PA 15260

Tel: (412)624-9245

Fax: (412)624-9163

e-mail: blc@pitt.edu







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