Re: Fw: Glass-Based Radon Measurements

["Tony Harrison" <Tony.Harrison@state.co.us>]

The study in question has a number of problems, English as a second

language being one, results that are statistically insignificant being

another.  Kai's question about the computed relative risk is a good one,

because the proportion of cases in the 80-140 Bq m-3 is lower than that

of the 50-80 Bq group, and equal to the <50 Bq group.  Above 140 Bq the

RR climbs again.  95% CI's for all results include 1.  This shows the

uncertainty that arises from doing statistics on small numbers; more

controls would have helped. 



The authors calculated the RR by logistic regression, adjusting for

age, sex, "occupational lung cancer risk" and other dubious factors. 

Given that the paper was "peer-reviewed" some would say the results are

good as gold.  Only the authors know for sure, and good questions should

be directed to them.



The point of the paper, however, was not lung cancer risks, but that

glass based measurements provide a better basis for long term dose

assessment than air samples, a claim that has been made in other papers.

 I think the jury is still out on that one, and we can honestly say that

it needs further investigation.



"Don't worry boys, we'll weather this storm of approval and come out of

it more hated than ever."  - Saul Alinsky





Tony Harrison, MSPH

Colorado Dept. of Public Health & Environment

Laboratory and Radiation Services Division

(303)692-3046

tony.harrison@state.co.us





>>> <hflong@postoffice.pacbell.net> 09/10/02 01:59AM >>>

Kai and Radsafers,

I, too, have trouble understanding the permutations of case control

studies and

radon variability, glass -based measures, etc.



Howard Long



Kai Kaletsch wrote:



> Friends,

>

> As a result of my request, a radsafer has sent me a copy of the

Lagarde et

> al. paper. I still seem to have a problem wrapping my head around

this

> case - control stuff. I would very much appreciate it if someone

could take

> the time to help me out (if you want to see the paper, you can get to

a pdf

> version from

> http://www.nature.com/jea/journal/v12/n5/index.html ):

>

> According to the first row of Table 4 of the Lagarde et al. paper

there are

> 33 cases and 58 controls in the 50 to 80 Bq/m3 category ( i.e. 1.76

controls

> per case) and 24 cases and 55 controls in the 80 to 140 Bq/m3

category (

> i.e. 2.29 controls per case). Relatively speaking, there are 30 %

more

> healthy people (controls) in the higher dose category than in the

lower dose

> category. Yet, the authors calculate a higher relative risk for the

80 to

> 140 Bq/m3 category than in the 50 to 80 Bq/m3 category (1.42 vs.

1.28).

>

> To me, that doesn't make any sense. If you asked me if I wanted to

belong to

> a group that is full of sick people or to a group that is full of

healthy

> people, I would answer: "I want to belong to the group that has lots

of

> healthy people, because that means my risk of becoming sick is

lower."

>

> Could someone please try to explain this in common sense terms?

>

> Thanks in advance,

> Kai



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