Re: Radon, smoking and LNT

[Kai, Kaletsch]

You probably missed one of the more important reasons why temporal change in

radon is less important in your study than in case control:



Radon concentration in a house is a function of both the properties of the

house AND the lifestyle of the occupants. (The second factor seems to be

usually ignored.) In case control studies, the radon measurements in the

houses of cases are either made when a sick person is occupying the

premises, or after the cases are no longer living in the houses. In either

case there is a substantial change in lifestyle, between when the radon

exposure occurred and when the measurement was done.



That means that case control studies, almost by definition, are biasing the

results. The only question is: in which direction and by how much?



Have any studies been done by how much the radon levels in the living

quarters change with lifestyle, if no physical changes are made to the

house? How would the radon levels in the same house compare if the occupants

were having a party on the patio with the back door open every evening, as

compared to the radon level in the house with the occupant being sick in bed

and the doors and windows shut?





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

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

To: "Kai Kaletsch" <kai@eic.nu>

Cc: "RadSafe" <radsafe@list.vanderbilt.edu>

Sent: Tuesday, July 01, 2003 11:25 AM

Subject: Re: Radon, smoking and LNT





>

> On Tue, 1 Jul 2003, Kai Kaletsch wrote:

>

> >

> > From: "BERNARD L COHEN" <blc+@PITT.EDU>

> >

> > > 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. I have given reasons why it is

less

> > > important in my studies than in case-control stusies.

> >

> > Could you please repeat the reasons why the temporal change in radon is

less

> > important in your study than in case control? (or give the reference.)

>

> --I have used different time periods for lung cancer deaths and

> they give the same results. I have studied variation of radon levels with

> age of houses, indicating that radon levels have not changed radically

> with date of construction. It is more likely that radon level in a given

> house changes with time than that the county average radon level changes

> with time -- for example, pathways for radon into and out of the house can

> change with cracks opening and closing, or with change in ventilation

> practices like opening windows, etc, but these average out for the county

> average.

>

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