Re: Radon, smoking and LNT

[Kai, Kaletsch]

From: <epirad@mchsi.com>



> ....  Our findings to date indicate that there is little change when

> someone gets sick in window opening behaviors, home temperature change

etc.

> This is also supported by self-reported behavior of window opening etc. in

our

> questionnairre data.



I would prefer more quantitative data, such as changes in gas and

electricity consumption between before and after diagnosis (normalized to

the control group). Maybe one could focus on glass based dosimetry on

objects that were given away (to people living in apartments or other low

radon places) before diagnosis?



In any case, it is a systematic error and even a small systematic error

(unlike a random error) can have a big effect.



> Nevertheless, recall that in a case-control study, exposure

misclassification

> will bias toward the null,



This type of systematic misclassification will not bias toward the null. If

you want, I can give a numerical example.



Kai



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

From: <epirad@mchsi.com>

To: "Kai Kaletsch" <eic@shaw.ca>

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

Sent: Wednesday, July 02, 2003 8:02 AM

Subject: Re: Radon, smoking and LNT





> Kai,

>

> We considered that factor and are in the process of looking at radon

> concentrations in many of our study homes for a 3rd year.  This is

something

> we considered when we set the inclusion criteria for our subjects, the

median

> time our subjects lived in the SAME home was 32 years.

>

> SEE: http://radsci1.home.mchsi.com/irlcs.pdf

>

> The point you bring up is the major reason we are looking at multi year

radon

> measurements.  Our findings to date indicate that there is little change

when

> someone gets sick in window opening behaviors, home temperature change

etc.

> This is also supported by self-reported behavior of window opening etc. in

our

> questionnairre data.

>

> We have noted that we do see more change (mixed higher and lower) when

someone

> else (For example, a new family) occupies the home other than the the

initial

> homeowner family, that is one reason we performed rapid-reporting of lung

> cancer cases in the Iowa Study so that we could get a high percentage of

> living case subjects in the study.  After the initial diagnosis of lung

cancer

> for our subjects, we were out at the home placing detectors within a

month.

>

> We are further investigating this in Iowa and Missouri through the use of

> glassed based detectors that provide a retrospective assessment of

exposure

> over the time period the glass item was in place in the home.

>

> Nevertheless, recall that in a case-control study, exposure

misclassifaction

> will bias toward the null, UNLIKE an ecologic study where

misclassification of

> exposure will cause unbounded bias in either the positive or negative

> direction.

>

> An example of the effects of exposure misclassification can be seen here:

> http://www.aarst.org/news_pdf/2002_IowaU_Follow-up_Study.pdf

>

> Note how poorly even year long basement radon measurments performed.

>

> In ecologic studies a large proportion of the measurements come from short

> term basement measurments.

>

> The bottom line is that sparse ecologic data can not adequately capture

the

> exposure of interest or control for confounding as further supported by

Dr.

> Puskin's paper.

>

> Bill Field

> > 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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