Subject:  Brain tumor studies (Kundi).
Date:     Fri, 22 Dec 2000 053622 -0600
From:     Roy Beavers 
To:       guru 
--------------------------------------------------

........From EMF-L.......

This response certainly deserves some serious consideration......guru...

-------- Original Message --------
Subject: Brain tumor studies
Date: Fri, 22 Dec 2000 12:18:39 +0100
From: Michael Kundi 
To: Roy Beavers 

Dear Roy,
In your comment on the recently published brain tumor studies you stated
correctly that there are a number of hypotheses which should be tested
in epidemiological studies and that the Muscat (and Inskip) study tested
only the hypothesis that 'cellphone use does not normally influence
brain cancer development'. It might be no surprise to you that in these
studies not even that hypothesis could be tested. It is by far too
general. First of all, there is no such thing as 'brain cancer'. What is
called brain cancer is a multitude of completely different entities
(that have their origin in different tissue types, are slowly or fast
growing, and have different etiology and predisposing factors). If
cellphones influence brain tumor development (without affecting
incidence) there are at least two possibilities: There could be an
influence on speed of development and there could be a reduction of
latency from malign transformation to the onset of clinical symptoms.
For the first possibility there are again at least two hypotheses: The
dissipation of heat in superficial regions of the brain (especially at
the temporal lobe) could reduce the speed of development because
hyperthermia is a known tumor growth inhibiting factor, and the exposure
can lead to a faster development due to its possibly promoting
potential. Again these mechanisms will have an impact which depends in
the type and localization of the tumor. Both studies did not have enough
power to detect any of these effects. Not even an attempt was made in
these studies to test the assumption that exposure could increase speed
of tumor development. This would have involved inspection of the
patients records for early clinical signs and to determine the duration
until tumor diagnosis. A further problem of these studies is that they
didn't account for latency. If cellphones influence tumor development at
an early stage only exposures which have occured maybe many years ago
(depending on type of tumor) should be included. To cumulate exposures
up to hospital admission is nonsense given the hypotheses that were
tested (it makes, however, sense if the tumor growth rate would have
been analysed).
Best regards and Merry Chrismas,
Michael Kundi
--
Department for Occupational and Social Hygiene
Head:Univ.Prof.Dr.Michael Kundi
Institute of Environmental Health
University of Vienna, Austria
Kinderspitalgasse 15
A-1095 Wien
Tel: +43-(0)1-40490 64726
Fax: +43-(0)1-4277-9647


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Reprinted with permission of Roy Beavers, http://www.emfguru.com