Putting a
spin on science:
the NCI Linet
Study
On Friday July 4, 1997, both The Australian and
The Sydney Morning Herald featured articles about the
just released U.S. National Cancer Institute study,
conducted by Dr. Martha Linet and co-workers, in
which it was claimed that there was no evidence that
powerline electromagnetic fields increase childhood
leukemia risks. This study was published July 3rd in
the New England Journal of Medicine. Most of the
media and power industry supporters are claiming this
study exonerates powerline EMFs as a health hazard.
As reported by CNN on July 2, 1997; "Children
exposed to electromagnetic fields by living near
electrical power lines are not more susceptible to
developing leukemia, a study released Wednesday
shows."
Don MacPhee fron Latrobe University's school of
microbiology states in The Australian that the
results of the NCI Study backed his claims that power
lines did not emit enough energy to cause childhood
cancer or any other form of cancer. Mac Phee said
that it was mostly the media and scientists of
"Dubious Quality" that had perpetuated the
myth that there was any link between power lines and
cancer. "Its just absolute non-sense", Dr.
McPhee said.
This line is also being actively pushed by the
media in the US, the U.K. and Europe and is being
promoted as proof that future funding for research
should cease.
These claims can not be scientifically
justified, as the following will illustrate.
The view that powerline EMFs do not emit enough
energy to effect cellular processes is at odds with
recent research conducted by respected bio-effects
researcher Dr. Om Gandhi. In March 1997 at a science
symposium on cellular studies convened by the U.S.
National Institute of Environmental Health Sciences
(NIEHS) in Durham, North Carolina, and reported in
the U.S. based publication Microwave News, "Dr.
Gandhi reported that the fields induced in the human
body by power lines and appliances indeed,
essentially all strong EMF sources - are much
stronger than the fields generated naturally inside
the body. Or, in the jargon of the trade: the
exogenous EMFs dwarf the endogenous fields. Gandhi,
who is at the University of Utah in Salt Lake City,
used a computer model to calculate the electric and
magnetic fields in the 41 - 70 Hz frequency band from
internal and external sources.
The human heart is the strongest and most
consistent source of EMFs, but even its fields in
other organs are hundreds of times smaller than those
induced by standing under a high - voltage power line
or by using a hair dryer. "My assumption was
that what is already in the body is pretty
substantial, but that turns out to be
incorrect," Gandhi said in an interview. He
noted that he was "surprised" by his
results. "It is time for people to reject false
assumptions," he said." (Microwave News,
May/June 1997)
It is unfortunate that reporters and so-called
experts who are now calling the NCI study as positive
proof that a risk does not exist from long term
exposure to powerline electromagnetic fields did not
take the time to critically examine what the study
had actually found, and also to examine the criteria
which led to the NCI researcher's conclusions.
The NCI researchers actually acknowledge in no
less than four places, a statistically significant
increase in acute lymphoblastic leukaemia (ALL) in
children exposed to powerline magnetic fields in
excess of 3 milliGauss . This is a confirmation
of many previous studies which have shown a similar
level of association between childhood leukaemia and
magnetic fields from electricity. The article in The
Australian mentions that the researchers dismissed,
as a "statistical fluke", a 24% increase in
leukemia risk for children exposed to what is termed
"especially high magnetic fields".
The NCI researchers were able to dismiss this fact
by arbitrarily setting a 2 mG level as a cut-off
limit. The fact is, that if they had used the 3 mG
level as a cut off point in their calculations, the
conclusions would have been exactly the opposite - that
there is a significant risk.
On July 4th EMFacts e-mailed Professor Ross Adey,
one of the most respected bio-electromagnetic
researchers in the U.S., Dr. Adey is the author of
numerous books and research papers on the bio-effects
of EMFs. He recently conducted a $3 million research
program for Motorola. His reply on the NCI study is
as follows:
"A number of us worked on the NCI paper
through last weekend. Sam Milham, the Washington
State epidemiologist and a pioneer in this field,
points out that if they had included the 3mg level in
their cutoff, the conclusions would have been exactly
the opposite - that there IS a significant risk, and
selection of 2mG is quite arbitrary. David Savitz
used 3mG in some of his work. Obviously there is no
steep threshold beyond which risks rise
exponentially.
At the recent Bologna International Symposium,
Scuz from U. Mainz had a paper combining kids from
Berlin and Southern Saxony in high exposure homes to
give leukemia odds ratio of 6.8 for young kids (under
4yrs). So the dismissive attitude of NCI is totally
unrealistic."
As stated in a July 2 press release on the Linet
study, by British researcher Alasdair Philips from
Powerwatch Network; " The Linet study, billed by
the NCI as "The most comprehensive study ever
done on this much-debated topic", falls far
short of its billing as the study does not approach
the thoroughness of the earlier Swedish studies, and,
incredibly for a modern study it only measured
magnetic fields and did not include electric
fields which are being increasingly implicated in
cancer development and many other adverse health
conditions. Both magnetic and electric fields are
being measured in the landmark UK Childhood Cancer
Study due out early next year, as UK researchers
understand the potential importance of electric
fields. In a 1996 study on adults which took both
fields into account, the risk rose from 1.6 (magnetic
fields only, and similar to the 1.79 in this study)
to 11.2 (both magnetic and electric fields
considered) - it is likely to be a similar increase
for children."
It should also be noted that the magnetic field is
not the equivilant of EMF. It is only one of the now
"five or six" known EMF metrics. Of these,
the electric field may well be the most important,
though the role of transients, harmonics, ground
currents, radon daughters and the radiofrequencies
that "ride" on power lines are also
suspect. Any study which only considers one of these
metrics cannot give any assurance of
"safety".
If we extrapolate to the evidence
(Electromagnetics Forum, Vol.1, No.2, p.5-6 ) that
levels of 12 mG affect the ability of melatonin to
suppress cancer cells and that there is some evidence
of a dose-response relationship between 2 and 12 mG,
then at levels at or below 2mG, a no effect result
could well be expected.
With this in mind, the only thing the NCI
indicates is that children with magnetic field
exposures at 2 mG and under are not at increased risk
of developing leukemia from their EMF exposure.
Rather than exonerating EMFs, the NCI study gives
further support for the 1995 draft guidelines from
the U.S. National Council of Radiation Protection and
Measurements. (NCRP) These guidelines generally
endorse a 2mG exposure limit.
As stated in the NCRP's conclusions:
"In arriving at the proposed guidelines, the
committee has considered available laboratory studies
on bioeffects and epidemiological reports of health
hazards from electric and magnetic field exposure In
key areas of bioelectro-magnetic research, findings
are sufficiently consistent and form a sufficiently
coherent picture to suggest plausible connections
between ELF EMF exposures and disruption of normal
biological processes, in ways meriting detailed
examination of potential implications in human
health." (For more information on the NCRP
Guidelines see Electromagnetic Forum, Vol.1, No.2,
Autumn 1997)
The NCI study can be put into the same
classification as the NAS/NRC review study.
(Electro-magnetics Forum, Vol.1, No.2, p.1-4 ) Both
studies come up with conclusions based on serious
omissions of hard scientific data which do not fit in
with those conclusions. Both these studies are now
being used by those wishing to end further EMF
research.
When you look at the tobacco health issue history,
you will find that similar efforts to stop or curtail
research spending was one of the tactics used- along
with belittling research finding that indicated a
health hazard existed. For some years those attempts
to stymie research on the tobacco problem were
successful. Lets hope that tactic will not be
successful here.
The National Cancer Institute may well consider
that research money should be better spent in other
areas than EMF research. To be fair to the NCI, when
you consider the millions prevously spent on EMF
research and that figures indicate that the number
who live above 2mG in the U.K., Sweden and Italy is
only estimated to be about 0.5% of the population,
there is a need to re-prioritise future research. The
many large and expensive epidemiological studies that
looked at magnetic fields only have really "had
their day". They show that there is an effect,
maybe on a susceptible sub-group in the population,
and the effect is NOT very large for magnetic fields
alone. It is now time to think very carefully how we
spend the millions, to carefully look at the other
metrics of EMF exposure as mentioned earlier, also to
adopt a policy of prudent avoidance, along the lines
recommended by the draft NCRP report.
World Conference on Breast
Cancer's press release on the NCI Linet Study:
At The First World Conference On Breast Cancer,
held at Queens University, Kingston, Ontario, Canada,
from 13 to 17 July 1997, many concerns were raised on
the calls for ending future EMF health effects
research, based on the NCI Linet study.
The following is a joint press release from that
conference:
Dateline: 1st World Conference on Breast Cancer,
Kingston, Ontario, Canada , July 15, 1997.
"The recent report in the New England Journal
of Medicine by Linet and colleagues has been widely
reported as showing no link between exposure to
electromagnetic fields (EMF) and one type of leukemia
in children. On the basis of this new study, some
scientists and some news media organisations,
including the major networks, have repeated the
questionable claim that the link between EMF exposure
and cancer risk is no longer an issue, and further
research is unnecessary.
Such statements, based on a single study, are
troubling. More disturbing still, is the fact that
the data presented in the Linet study do not support
the assertion that no link exists. Even a cursory
review of the main data set shows a 53% increase in
leukemia incidence at magnetic field exposure levels
above 2 mG; a 72% increase (which is statistically
significant) above 3 mG; and a more than 600%
increase at exposures of between 4 and 5 mG. Above 5
mG, no link is shown, but there are too few cases in
this range to yield any significant result.
Dr. Bary Wilson, who has co-authored a recent book
on EMF and breast cancer, and several other speakers
at the World Conference on Breast Cancer, including
Dr. Kjell Hansson Mild of National Institute of
Working Life in Sweden, have stated that a study
which is apparently positive and limited only to
leukemia should not be used to discount a possible
link between EMF and cancer in its entirety.
Any statement claiming the demise of the EMF and
cancer issue should be based on an analysis of all
the available data and not one study, particularly
one in which the reported data are apparently not
reflected in the conclusions. In fact, available data
on the subject, provided by many scientists over more
than a decade, do not support the hypothesis that
there is no link between EMF exposure and increased
risk for several types of cancer.
Cindy Sage of Sage Associates and Chair of the EMF
program at the conference points out that, "even
a small increased risk of breast cancer due to EMF
exposure has enormous public health implications
given the high incidence of this disease in developed
countries."
Based on the Linet, et al. study, it is clearly
not justified to call for the end of research into
the possible !ink between EMF and cancer. Given the
growing body of evidence for a possible link between
EMF and breast cancer, in particular, cessation of
research funding at this time would be reckless and
scientifically indefensible."
·Kjell Hansson Mild, Ph.D.
Natl lnst for Working Life, Sweden
·Cindy Sage
Sage Associates, USA
·Bary W. Wilson, Ph.D.
Pacific Northwest National Laboratory, USA
Comments to the NCI .c.by
Allen H. Frey,
Allen Frey is the author of "On the
nature of electromagnetic field interactions with
biological systems ", RG Landes Co., Austen
TX, USA, 1994.
"Are the conclusions of the Linet et al
epidemiological study and associated editorial by
Campion justified? I think not.
The fault, as is often the case in science, is in
assumptions made before the study began, assumptions
upon which the study is based. If the assumptions can
not be shown to be true, then the conclusions are not
valid.
In their statistical study, it was assumed that
the active agent in power line biological effects is
the 60Hz sinusoidal wave. But there is substantial
data and biological theory that indicate the primary
active agent would be the transients that are found
on power lines in varying forms to varying degrees in
various places (Frey, 1994). A broad statistical
study such as Linet et al's would tend to obscure
such effects since data from areas where there are
effective transients would be submerged in the mass
of data from areas where there are not such
transients.
Epidemiological studies, and statistical studies
in general, are quite useful for hypothesis
generation. But they are not appropriate for drawing
conclusions. Causality can not be shown. There are
just too many unknown and uncontrolled factors
operating in a large statistical study, as compared
to wet biological experiments. This is particularly
the case with magnetic fields as an agent, for it is
not yet clear what parameters of the agent are of
importance biologically.
Is it appropriate to draw what may be life and
death conclusions on the basis of one statistical
study that is based on an assumption about what is
the active agent, an assumption that can not be shown
to be true? I doubt that many people would be willing
to stake their life on one such study."
Comments to NCI by A. R.
Liboff,
A. R. Liboff is Professor of Physics,
Oakland University, Rochester, MI, USA.
"Like Allan Frey, I too have doubts
concerning the implications of the Linet study. Frey
points to the possibility of transients as the metric
underlying the earlier correlations.
Another possibility is that the geomagnetic field
may be a complementary factor, either because of
cyclotron resonance or some other type of resonance
interaction. In connection with this it appears that
Denver was not one of the areas examined, which is
puzzling considering the fact that data from the
Denver vicinity was the impetus for such
epidemiological studies.
The media has characterized this study as the
largest yet. For some time, I have had the feeling
that funding for such studies would continue until
the funders got the answer they wanted. Never mind
the original objections to the Wertheimer and Savitz
results that epidemiological studies were
"innately non-scientific" and did not prove
anything. Now that the results are more in line with
what is desired, we are subjected to newspaper and TV
reports saying that this report is the final word.
Nowhere does the media awaken the public to the
fact that since Wertheimer's original 1979 results,
there has arisen a wealth of (laboratory) evidence
showing that ELF magnetic fields can have profound
effects on living things. What in 1979 seemed
inconceivable no longer appears improbable.
Perhaps now that we have had, in the words of the
media, the "final word", the rest of us can
get on with the science underlying these ELF
interactions and, through the science, determine the
consequences for human hazard."
