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RE: Radon-Stirring the Pot
Good morning all,
I read again the following reference
1.Lubin, and J. Boice Jr., “Lung cancer risk from
residential radon: Meta-analysis of eight epidemiologic
studies,” J. Natl. Cancer Inst. 89, 49-57 (1997).
Fig 1 in the paper shows a wide dispersion of relative risk vs Radon
concentration around the no effect line. Confidence intervals for all
Relative Risk points, with 2 exceptions, include 1. From the graph
itself it is impossible to detect an effect, either way. The authors
say that the combined trend for all RR is 0,03, p=0.03, significantly
different from zero.
Could someone explain the statistical or practical meaning of "trend" in
that context and give references? Plain English explanation would be
welcome. In the few textbooks I checked trend refers generally to time
trends.
Thank you in advance
Philippe Duport
International Centre for Low-Dose Radiation Research
Institute of the Environment
Universirty of Ottawa
555 King Edward Ave.
P.O. Box 450, Stn. A
Ottawa, Canada, K1N 6N5
Tel: (613) 562 5800, ext. 1270
pduport@uottawa.ca
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of epirad@mchsi.com
Sent: September 19, 2002 2:38 PM
To: radsafe@list.vanderbilt.edu
Subject: Re: Radon-Stirring the Pot
The basis for the BEIR VI risk estimates are derived
mainly from extrapolations from radon-exposed miners. I
think both BEIR IV and BEIR VI provides the evidence to
suggest prolonged radon progeny exposure is the second
leading cause of lung cancer, but as you know this is a
seemingly never ending debate.
Regarding direct evidence - Residential Radon Studies.
Analytic epidemiologic studies (not ecologic) are used
to infer whether causal associations are appropriate or
not.
The main factors that must be considered in determining
causality from epidemiologic studies are: consistency of
results from case-control studies, chance (how likely
are the findings from all positive studies due to
chance?), bias (has potential sources of bias been
identified), strength of association, dose response,
temporality (disease occurs within a biologically
reasonable time period after exposure), and biological
plausibility (the association makes sense in light of
what is known biologically).
These factors should all be considered in making causal
inferences from analytic epidemiologic studies. In many
cases, lack of consistency among studies can be
explained when there are good explanations for
inconsistencies in studies such as small sample size or
poor retrospective exposure assessment. For example,
the more rigorous recent case-control studies (see
below) have consistently shown a positive association
between residential radon exposure and lung cancer, even
in non smokers.
Also, see debates elsewhere:
http://www.ntp.org.uk/951-TUD.pdf
1.Lubin, and J. Boice Jr., “Lung cancer risk from
residential radon: Meta-analysis of eight epidemiologic
studies,” J. Natl. Cancer Inst. 89, 49-57 (1997).
2. L. Kreienbrock, M. Kreuzer, M. Gerken, G. Dingerkus,
J. Wellmann, G. Keller, G. and H.E. Wichmann, “Case-
control study on lung cancer and residential radon in
western Germany.” Am. J. Epidemiol. 153, 42-52 (2001).
3.S. Darby, E. Whitley, P. Silcocks, B. Thakrar, M.
Green, P. Lomas, J. Miles, G. Reeves, T. Fearn, and R.
Doll, “Risk of lung cancer associated with residential
radon exposure in South-West England: a case-control
study,” Brit. J. Canc. 78, 394-408 (1998).
4. Z. Wang, J.H. Lubin, L. Wang, S. Zhang, J.D. Boice
Jr, H. Cui, S. Zhang, S. Conrath, Y. Xia, B. Shang, et
al., “Residential radon and lung cancer risk in a high-
exposure area of Gansu Province, China,” Am J Epidemiol,
155, 554-64 (2002).
5.D. Krewski, J. Lubin, J. Zielinski, M. Alavanja, V.
Catalan, R.W. Field, J. Klotz, E. Létourneau, C. Lynch,
J. Lyon, D. Sandler, et al., “A combined analysis of
North American studies of lung cancer and residential
radon exposures,” American Statistical Association
Conference on Radiation and Health, Deerfield Beach,
Florida, (2002).
6. M.C. Alavanja, J.H. Lubin, J.A. Mahaffey, and R.C.
Brownson, “Residential radon exposure and risk of lung
cancer in Missouri,” AJPH, 89, 1042-8 (1999).
7. R.W. Field, D.J. Steck, B.J. Smith, C.P. Brus, J.S.
Neuberger, E.L. Fisher, C.E. Platz, R.A. Robinson, R.F.
Woolson, and C.F. Lynch, “Residential radon gas exposure
and lung cancer: the Iowa radon lung cancer study,” Am.
J. Epidemiol. 151(11), 1091-1102 (2000).
8. M. Kreuzer, M. Gerken, L. Kreienbrock, J. Wellmann,
and H.E. Wichmann, “Lung cancer in lifetime nonsmoking
men - results of a case-control study in Germany.” Br.
J. Cancer 84(1) 134-40 (2001).
9. F. Lagarde, R. Falk, K. Almren, F. Nyberg, H.
Svensson, G. Pershagen, “Glass-based radon-exposure
assessment and lung cancer risk,” J. Expo. Anal.
Environ. Epidemiol. 12, 344-54, (2002).
Bill Field
bill-field@uiowa.edu
> Ruth Weiner wrote:
> Epidemiological studies do not "prove," or even show, causality; they
show
> correlations, and correlation is not causality. I belive that at
least part
> of the epidemiological basis for this statement is the "Iowa Study" of
Field
> et al. I wouldn't draw this conclusion from the Iowa Study, but then
I am
> not an epidemiologist either.
>
> I would like to see both Bill Field 's and bernie Cohen's response to
these
> questions.
>
> Ruth.
>
> Ruth Weiner, Ph. D.
> ruthweiner@aol.com
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