From: jmoulder@mis.mcw.edu
Newsgroups: sci.med.physics
Subject: Re: High voltage transmision lines and human health
Date: 27 Jul 92 16:29:01 GMT
Organization: Medical College of Wisconsin

btbg1194@uxa.cso.uiuc.edu (Bradley T Banko) writes:
>>
>>IMO:
>>1) From a review of epidemiological studies of residential populations
>>exposed to power frequency EMFs I conclude that these studies do not 
>>*show* that such fields *cause* cancer. 
> 
>>2) From a review of epidemiological studies of occupational groups exposed to
>>power frequency EMFs I conclude that these studies do not *show* that such 
>>fields *cause* cancer. 
> 
> I don't what criteria you use for "proving" causation (dose-dependence, etc.),
> but I do remember seeing one study which concluded that there was a
> significant correlation between electric power cable splicers and an
> increased incidence of some cancer. 
>

The criteria I'm using:

1) Strength of the association: How high are the relative risks? 
A recent meta-analysis (GB Hutchison,Health Environ Digest 6:1-4, 1992) 
derives the following relative risks:
Childhood leukemia, residential exposure   1.3 (0.9 - 2.0)
Adult leukemia, occupational exposure      1.1 (1.0 - 1.2)
Childhood CNS cancer, residential exposure 2.4 (1.5 - 3.7)
Adult CNS cancer, occupational exposure    1.2 (1.0 - 1.5)
Adult, all cancer, occupational exposure   1.0 (0.8 - 1.1)

2) Consisteny:  Baring a common bias, many studies with similar relative risks
are stronger than a single sudy.
A recent review (MN Bates, Environ Health Perspec 95:1470156, 1991) reports that
there are some consistencies, particularly in studies of leukemia and brain
cancer among electrical workers, and brain cancer in children exposed to
residential ELF fields

3) Dose-response relationship.  
No study of residential exposure has shown a dose-response relationship between
measured magnetic fields and risk.  Some studies have shown a weak 
dose-response relationship between wire codes and risk.  Essentially none of
the occupational studies involve actual measurements of exposure, so the
issue of dose-response is moot.

4) Biological plausibility: The plausibility of deriving a cause-effect
relationship from an epidemiological correlation is enhanced when results
of experimental animal and cell studies support the epidemiology.
So far, ELF fields have not been shown to be carcinogenic in animals or
genotoxic in cells.   

>>3) From a review of epidemiological studies of human exposures to power
>>frequency EMFs I conclude that one can *speculate* that these fields might in
>>some way *influence* cancer risks.
> 
> On the other hand, a paper by that "baseball" physicist at Yale looked at
>                                               (Robert Adair)
> the matter in somewhat theoretical terms, and concluded that there should
> essentially be no effect from ELF fields (resonance absorption on a cellular
> level), if I remember right.

Yes, Adair (Phys Rev A 43:1039-1048, 1991.) argues that biological effects 
of weak ELF effects at the cellular level, if they exist, must have 
explanations outside the scope of conventional physics.  

I'm not very comfortable with this argument.  
I recall a paper from college biology in which an engineer demonstrated that 
hovering of humming birds was an optical elusion, as hovering was "impossible".
 
I also recall a paper from the early 1950's that demonstrated that ionizing
radiation could not kill cells because the amount of kinetic energy delivered 
paper exists, if anyone can verify a reference, I would appreciate it].

In this context, see Jackson (Proc Nat Acad Sci USA 89:3508-3510, 1992) who 
argues that the lack of a historic correlation between electrical power
generation and the incidence of cancer eliminates the possibility that 
power-frequency fields are a significant cause of cancer.

John Moulder (jmoulder@mis.mcw.edu)
Radiation Biology
Medical College of Wisconsin
Milwaukee, WI   414-266-4672
Newsgroups: sci.med.physics