- Recent
Studies: EMF
effects on melatonin
-
- In the lead article of the inaugural
issue of Electromagnetics Forum, (Aug-DEC
1996), EMFs, Melatonin and Breast Cancer,
three replication studies, presented at
the 1996 BEMS Meeting in Victoria,
Canada, were mentioned. These studies
found that low level (12 milliGauss)
exposure to 50-60 hertz electromagnetic
fields (EMFs) can significantly reduce
melatonin and Tamoxifen's ability to
suppress breast cancer cells. Melatonin,
produced by the pineal gland, is a potent
cell protection and anti-cancer agent.
Tamoxifen is one of the most widely used
drugs in the treatment of breast cancer.
-
- In the 1987, Steptens, et al paper,
Electric power use and breast cancer; a
hypothesis, it was suggested that
electromagnetic fields (EMFs) reduce
melatonin production by the pineal gland
and that melatonin suppresses the
development of breast cancer. (*1)
-
- Research in 1993 by Liburdy, et al, found
that melatonin reduces the growth rate of
human breast cancer cells (MCF-7) in
culture, but that a 12mG, 60 Hz magnetic
field can block the ability of melatonin
to inhibit breast cancer cell growth.
(*2)
-
- To briefly mention these three
replication studies:
-
- 1) Lawrence Berkeley National Laboratory:
Researchers found that a 12mG
electromagnetic field can significantly
reduce the growth inhibitory action of
melatonin and Tamoxifen on breast cancer
cell (MCF-7) growth. (*3)
-
- 2) U.S. Environmental Agency: Researchers
found that melatonin can inhibit the
growth of MCF-7 cells in culture and that
a 12mG, 60 hertz magnetic field can
completely block this oncostatic action.
(*4)
-
- 3) Lawrence Berkeley National Laboratory:
Researchers found that12mG computer
monitor magnetic fields also inhibit the
ability of melatonin to suppress breast
cancer cells in vitro. (*5)
-
- A further replication of these three
findings was made by the Division of
Biomedical Sciences, University of
California, where Richard Luben and co
workers "found that exposure of
breast cancer cells to 2mG, 60 Hz EMF
induced a reproducible net increase in
the growth rate of MCF-7 cells treated
with a physiological dose of
melatonin." (*6)
-
- Many laboratory studies have not found
the above effects, as researcher Dr. John
Reif of Colorado State University said to
Microwave News, "Most natural
observations appear to find melatonin
changes, while controlled lab studies
tend not to In a general way, I'm
concerned that the controlled lab trials
may not mimic exposures in the real
world." (*7)
-
- The following three recent human exposure
studies, as published in Microwave News
(Mar/Apr.1997), when compared with the
above replicated lab findings, will
ensure that the hypothesis that EMFs may
increase breast cancer risks will
continue to be an important issue.
-
- 1) A preliminary study of 60 workers at a
Finnish garment factory found "a
highly significant effect"of EMF's
in reducing nocturnal melatonin levels.
Magnetic field measurements were taken
for the two types of machines used in the
factory and operators were assigned to
high or low exposure groups, based on the
type of machine they were using, with
average exposures either above of below
10 milliGauss. Unexposed non industrial
workers were used as controls.
-
- The results of this study found strong
effects of both magnetic field exposure
and smoking on night time levels of
melatonin. No difference was found in
melatonin levels on week nights and
Sunday nights, indicating "that the
possible suppression caused by magnetic
field exposure is chronic, with little
recovery during the weekend," (*8) -
consistent with the effect of chronic
electric field exposure in the rat
experiments of Wilson et al. (1986) (*9)
-
- 2) In a study of 192 electric utility
workers, Drs. John Reif and James Burch,
from the Colorado State University, found
that some EMF exposures are associated
with lower levels of melatonin. They
found a significant association between
magnetic field exposures and lower
daytime melatonin levels on the second
and third of three days of measurement.
The lack of an effect on the first day
(following a weekend or equivalent) may
indicate a cumulative effect of exposure.
-
- Some studies have suggested that EMF
effects on melatonin may depend on
whether the field is continuous or
intermittent. Reif and Burch found that
magnetic fields in the home that were
"temporally coherent" (less
intermittent) had a very significant
impact on lower melatonin levels at
night. They concluded that, the
"intensity and temporal
characteristics of magnetic fields appear
to be involved in melatonin
suppression." (*10)
- 3) Office workers who used computer
monitors (VDU's) had a significant
reduction in circulating levels of
melatonin over a course of the working
day, according to a study by researchers
Drs. Bengt Arnetz of the Karolinska
Institute, and Mats Berg of the
Karolinska Hospital in Stockholn Sweden.
No such change was found during days at
the office with no VDU use. According to
the researchers, "this suggests that
there is a direct impact from the
electromagnetic environment of the VDU on
levels of melatonin."
-
- Levels of a different hormone,
adrenocorticotropic hormone (ACTH), went
up during the working day and this showed
a strong correlation with worker's
subjective assessment of mental strain.
Arnetz and Berg note that ACTH is
"known as a classic stress hormone
that reacts to mental strain." But
in contrast, "occupational strain
did not correlate with melatonin
levels." (*11)
-
- An excellent 776 page resource book on
this subject, The Melatonin Hypothesis:
Breast Cancer and Use of Electric Power,
edited by Drs. Richard Stevens, Barry
Wilson and Larry Anderson, all from
Battelle Pacific Northwest Labs. in
Richmond Washington, can be ordered from
Battelle Press for US$87.50 + $12.50.
post & handlingFax:
0011-1-614-424-3819,
- E-mail: <press@battelle.org>
-
- In the introductory chapter, the editors
state, "The body of evidence is
sufficient to bind electric power over
for trial, but not nearly adequate to
render a verdict."
-
- REFERENCES
-
- 1) Stevens, R.G. (1987) Electric power
use and breast cancer: an hypothesis,
American Journal of Epidemiology, 125:
p.556 - 561.
-
- 2) Liburdy, R.P. et al (1993) ELF
magnetic fields, breast cancer and
melatonin: 60 Hz fields block melatonin's
oncostatic action on ER+ breast cancer
cell proliferation. Journal of Pineal
Research, 14 (2): p.89 - 97.
-
- 3) Harland J.D., Liburdy R.P. (1996) ELF
Inhibition of Melatonin and Tamoxifen
Action on MCF-7 Cell Proliferation: Field
Parameters. BEMS Meeting Victoria,
British Columbia, Canada. Abstract A-1-1.
-
- 4) Blackman C.F. et al (1996) Independent
Replication of the 12mG Magnetic Field
Effect on Melatonin and MCF-7 Cells in
vitro. BEMS Meeting, Victoria British
Columbia, Canada. Abstract A-1-2.
-
- 5) Liburdy R.P., Afzay S.M.J. (1996)
Inhibition of Melatonin's Action of MCF-7
Cell Proliferation by Magnetic Fields
Associated with Video Display Terminals:
A Preliminary Study. BEMS Meeting,
Victoria, British Columbia, Canada.
Abstract A-1-3.
-
- 6) Luben R.A., Saraiya S. and Morgan A.P.
(1996) Replication of 12mG EMF Effects on
Melatonin Responses of MCF-7 Breast
Cancer Cells in vitro, Annual Review of
Research on Biological Effects of
Electric and Magnetic Fields from the
Generation, Delivery & Use of
Electricity, San Antonio, Texas; Nov.
19-21,1996. Abstract A-1.
-
- 7) Microwave News, Mar/Apr. 1997, p. 3.
-
- 8) Microwave News, Mar/Apr. 1997, p. 3-4.
-
- 9) Wilson B.W., Chess E.K. and Anderson
L.E. (1986) 60 Hz Electric Field Effects
on Pineal Melatonin Rhythms: Time Course
and Onset of Recovery.
Bioelectro-magnetics, 7:p. 239-242.
-
- 10) Microwave News, as above.
-
- 11) Microwave News, as above.
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