- Ontario Hydro Worker Study finds
significant leukemia risk
-
- In a large scale epidemiological study of
30,000 present and former male employees
of Ontario Hydro (Canada), Anthony Miller
and co-workers at the University of
Toronto, looked at the cumulative effects
of both magnetic and electric field
exposures on the cancer incidence. Most
epidemiological studies to date have
concentrated on magnetic field exposures,
assuming that they are the more
biologically active component of the
electromagnetic field. This study, and
the UK study Extra low frequency electric
and magnetic fields in the bed place of
children diagnosed with leukemia: a
case-control study by Coghill, Steward
and Philips (see article) indicate that
electric field exposures may play a major
role in the possible link between cancer
and 50-60 Hz powerline EMF's.
-
- "Up to now, people have tended to
pursue the notion that any cancer effects
were likely to be from magnetic
fields," said Dr. Anthony Miller
"However, this study suggests that
electric fields are potentially critical
to cancer risk."
-
- This would indicate that the risks as
found in previous epidemiological studies
which only considered magnetic field
exposures could well be understated and
throws into doubt the conclusions of the
NAS/NRC report, (see article - Page 1)
which did not include the Hydro data in
its own study.
-
- With the Ontario Hydro study, at the
highest level of exposure to both
magnetic and electric fields, the odds
ratio jumped from 3.51 to 11.2 when the
researchers included the interaction of
the effects of the two types of fields.
When asked which estimate was more
indicative of the actual cancer risk,
Miller replied, "The correct way to
think about it is the 11.2, because what
you're actually looking at is the
combined effects." Miller also said,
"What worries me is that so much of
the experimental cellular work that has
been done has screened out the electric
fields.
-
- "When people say they've done a
study that looked at magnetic fields and
there's nothing there, I can't
agree," Miller told the New York
based Microwave News. "What our
study says is, 'Well, you should have
looked at electric fields too.'" The
Ontario Hydro study reveals that workers
exposed to the combined electric and
magnetic fields had leukemia rates that
were 11 times greater than expected.
However, the risk was highest in relation
to electric field exposures and the
researchers concluded that the electric
field effect is dominant. The result of
the study was published in the July 10,
1996 issue of the American Journal of
Epidemiology.
-
- A study by Dr. Denis Henshaw and co
workers of the University of Bristol, UK,
also implicates the electric field. They
found that the decay products of radon -
a naturally occuring radioactive gas -
are attracted to powerline frequency
electric fields. ( see article )
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