Do magnetic fields cause increased risk of
childhood leukaemia via melatonin disruption?
Denis L Henshaw and Russel J Reiter
The authors
Denis L Henshaw
H. H. Wills Physics Laboratory, University of Bristol
Tyndall Avenue
Bristol, BS8 1TL, UK
and
Russel J Reiter
Department of Cellular and Structural Biology
University of Texas Medical Center
7703 Floyd Curl Drive
San Antonio
TX 78284-7762, USA
Childhood leukaemia
Childhood leukaemia was much less common 100 years ago and the incidence
continues to grow year-on-year. For example, the graph shows the large rise last century
in reported cases of infant leukaemia, ages 1 to 4. (UK Office for National Statistics CDROMs). The rise in the first part of the last century may be due to improvements in
diagnosis and to more children surviving infancy. However, most of the increase is likely
to be real and to have an environmental or lifestyle cause.
The hypothesis in outline
•
Chronic exposure to ELF magnetic fields reduces and/or disrupts the nocturnal
production and/or the action of the hormone melatonin in the pineal gland
•
Melatonin, whose properties have been extensively researched, is a powerful
radical scavenger and anti-oxidant which has been shown to be highly
protective of oxidative damage to the human haemopoietic system and in
animals of oxidative damage to the fetus
•
In cells, tissues, organs and whole animals, melatonin has been shown to
protect against damage from known carcinogens including ionising radiation
•
Therefore, chronic exposure to ELF magnetic fields increases the risk of
childhood leukaemia via melatonin disruption
The hypothesis – spin off
•
Although the doubling of childhood leukaemia risk associated with magnetic
fields above 0.3/0.4 µT suggests that magnetic fields may be a causal factor in
only a small number of cases, the association may turn out to be of
fundamental importance to the aetiology of childhood leukaemia
•
Because, if magnetic fields cause increased risk of childhood leukaemia via
melatonin disruption, then this would also implicate light-at-night as a causal
factor in childhood leukaemia
•
And, this would help to explain the increasing incidence of childhood
leukaemia in possibly a major way, given the ubiquitous nature and rate of
increase in light-at-night
•
However, apart from childhood leukaemia, melatonin could be a common
factor in the various apparently disparate adverse health outcomes associated
with EMF exposures: adult brain cancer, ALS and miscarriage and possibly
adult leukaemia, depression and suicide (California Health Dept EMF Report)
Melatonin
1. Hormone produced in
the pineal gland
during the night
2. Intrinsic to the human
circadian system
N-acetyl5-methoxytryptamine
5. Used to treat clinical
disorders such as
insomnia and depression
3. Powerful free
radical scavenger
4. Highly protective against oxidative
damage to the haemopoetic system
Melatonin continued…
•
Among its many properties, melatonin is a powerful radical scavenger and
antioxidant, more effective than either vitamins C or E. The hormone has been
found to protect nuclear DNA, tissues and organs against oxidative damage
from known carcinogens including radiation.
•
Melatonin is therefore a powerful natural anti-cancer agent.
•
The so-called “Melatonin Hypothesis” has been discussed in relation to the
significant rise in incidence of breast cancer in industrialised countries in
recent decades (Stevens 1987).
•
The risk is said to arise from reduced production of nocturnal melatonin
brought about by exposure to light-at-night (LAN) from domestic as well as
street lighting and magnetic fields associated with the electricity supply.
Melatonin
contd
•
Strong support for LAN affecting breast cancer risk has come from experiments in
animals. In rats, exposure to constant light leads to rapid development of mammary
gland tumours
•
Support in humans comes from the observation of reduced hormone-related cancer
rates in the blind and partially sighted and increased breast cancer rates in nightshift
workers (e.g. Hahn 1991, Feychting et al. 1998, Hansen 2001)
Reduced cancer rates in the blind and partially
sighted
•
Hahn, R. A., 1991. Profound bilateral blindness and the incidence of breast
cancer. Epidemiology, 2, 208-210.
•
Feychting, M. Österlund, B. and Ahlbom, A., 1998. Reduced cancer incidence
among the blind. Epidemiology, 9, 490-494.
•
Verkasalo, P. K., Pukkala, E., Stevens, R. G., Ojamo, M. and Rudanko, S-L.,
1999. Inverse association between breast cancer incidence and degree of
visual impairment in Finland. British Journal of Cancer, 80 (9), 1459-1460.
•
Hansen, J., 2001. Light at Night, Shiftwork, and Breast Cancer Risk. Journal
of the National Cancer Institute, 93 (No. 20), 1513-1515.
•
Swerdlow, A., 2003. Shift work and breast cancer: A critical review of the
epidemiological evidence. Research Report 132, ISBN 071762708X, HSE
Books.
Melatonin is highly protective of oxidative
damage to the haemopoietic system - 1
Experiment in human volunteers by Vijayalaxmi et al, 1996
Human volunteers were given 300 mg of melatonin. Blood samples were taken
immediately and one and two hours later. The blood was irradiated with 1.5 Gy of
gamma radiation (in humans this could be lethal)
A significant decrease (50 - 70%) in DNA damage was found in blood taken at two
hours compared with immediately after melatonin administration.
“The data may have important implications for the protection of human
lymphocytes from the genetic damage induced by free radical producing mutagens
and carcinogens”
Melatonin acts directly on the DNA to “mop up” oxygen radicals - Vijayalaxmi et
al, 1996. Mutation Research, 371, 221 -228.
Melatonin is highly protective of oxidative
damage to the haemopoietic system - 2
Experiment in mice by Vijayalaxmi et al. 1999
Mice pre-treated with zero, 125 and 250 mg of melatonin. Irradiated with 8.15
Gy of gamma radiation (lethal in humans)
After 30 days: 45% survival without melatonin; 85% survival with 250 mg
melatonin
Vijayalaxmi et al. 1999. Mutation Research, 425, 21-27.
Melatonin protects the haemopoietic
system against oxidative damage
•
•
•
•
•
•
•
•
Vijayalaxmi., Reiter, R. J., Herman, T. S. and Meltz, M. L. 1996. Melatonin and radioprotection
from genetic damage: In vivo/in vitro studies with human volunteers. Mutation Research, 371, 221 228.
Vijayalaxmi., Frei, M. R., Dusch, S. J., Guel, V., Meltz, M. L. and Jauchem, J. R., 1997. Frequency
of micronuclei in the peripheral blood and bone marrow of cancer-prone mice chronically exposed to
2450 MHz radiofrequency radiation. Radiation Research, 147, 495-500.
Vijayalaxmi., Reiter, R. J., Herman, T. S. and Meltz, M. L. 1998. Melatonin reduces gamma
radiation-induced primary DNA damage in human blood lymphocytes. Mutation Research, 497, 203
-208.
Vijayalaxmi., Reiter, R. J., Meltz, M. L. and Herman, T. S., 1998. Melatonin: possible mechanisms
involved in its ‘radioprotective’ effect. Mutation Research, 404, 187-189.
Vijayalaxmi., Meltz, M. L., Reiter, R. J., Herman, T. S. and Sree, K. K., 1999. Melatonin and
protection from whole-body irradiation: survival studies in mice. Mutation Research, 425, 21-27.
Badr, F. M., El Habit, O. H. M. and Harraz, M. M., 1999. Radioprotective effect of melatonin
assessed by measuring chromosomal damage in mitotic and meiotic cells. Mutation Research, 444,
367-372.
Jacob, S., Poeggeler, B., Weishaupt, J. H., Sirén, A-L., Hardeland, R., Bähr, M. and Ehrenreich, H.,
2002. Letter: Melatonin as a candidate compound for neuroprotection in amyotrophic lateral
sclerosis (ALS): high tolerability of daily oral melatonin administration in ALS patients. Journal of
Pineal Research, 33, 186-187.
Bonilla, E., Valero, N., Chacín-Bonilla, L. and Medina-Leedertz, S., 2004. Melatonin and viral
infections. Journal of Pineal Research, 36, 73-79.
Melatonin protects the fetus
•
Okatani et al. 1998. Maternal-fetal transfer of melatonin in pregnant women near term. Journal of
Pineal Research, 25, 129-134.
Reports rapid transplacental transfer of maternal melatonin to the fetus in women
•
Wakatsuki et al. 1999. Oxidative damage in fetal rat brain induced by ischemia and subsequent
reperfusion. Biology of the Neonate, 76, 84-91, and
Wakatsuki et al. 2001. Melatonin protects fetal rat brain against oxidative mitochondrial damage.
Journal of Pineal Research, 30, 22-28.
“Melatonin adminstration may prevent free radical-induced oxidative mitochondrial damage to fetal
rat brain by a direct anti-oxidant effect”
•
Absi, E., Ayala, A., Machada, A. and Parrado, J., 2000. Protective effect of melatonin against the 1methyl-4-phenylpridinium-induced inhibition of Complex I of the mitochondrial respiratory chain.
Journal of Pineal Research, 29, 40-47.
Melatonin may protect against the effect of several Parkinsonogenic compounds associated with
progressive impairment of mitochondrial function and increased oxidative damage
•
Okatani et al. 1997. Melatonin inhibits vasopastic action of hydrogen peroxide in human umbilical
artery. Journal of Pineal Research, 22, 163-168.
Melatonin significantly suppressed the vasospatic effect of H2O2 possibly due to its ability to
scavenge the hydroxyl radical
•
Okatani, Y., Wakatsuki, A., and Reiter, R. J., 2001. Melatonin suppresses homocysteine
enhancement of serotonin-induced vasoconstriction in the human umbilical artery. Journal of Pineal
Research, 31, 242-247.
Melatonin suppression by magnetic fields
Kato et al. 1993, 1994a, b, c, d and Kato & Shigemitsu (1997) found
evidence that circularly polarised but not plane polarised fields magnetic
fields reduced pineal melatonin in rats
The Consequences of Ellipticity
Power Density/ Induced Current
Percentage Increase in Power Density and Induced Current with
Ellipticity of Magnetic Field
220%
200%
Induced Current
180%
Power Density
160%
140%
120%
100%
80%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Ellipticity
0% =Linear Field
100% = Circularly Polarised
Powerline results (2):
Polarisation of the 50Hz magnetic field along a line underneath and
perpendicular to a 400kV powerline, Somerset
40%
35%
30%
Ellipticity
25%
20%
15%
10%
5%
0%
-30
-20
-10
0
10
Distance (m) 0 is under the centre of the line
20
30
Melatonin suppression by magnetic fields
I – short term volunteer exposures
• There have been a number of studies of effects of magnetic fields on pineal
melatonin production in volunteers exposed for relatively short periods.
Melatonin levels in the body are assayed either from blood samples (serum
melatonin) and/or from the melatonin metabolite 9-hydroxymelatonin sulphate
(6-OHMS) in urine
• These volunteer studies have at best provided possible evidence of pineal
melatonin suppression only after several days exposure
Melatonin levels: human volunteer studies over comparatively short periods of time
Authors
Wilson et al, 1990
Type of exposure
Duration of
exposure
Number of
volunteers / Assay
Response
Comment
60 Hz EMF’s generated
by pulsed AC or DC
current supply to electric
blankets
nightly for
7-10 weeks
32 female and 10 male
volunteers.
Early morning excretion of
urinary metabolite of
melatonin
No overall effect: transient
increases in 7/28 users of
one type of blanket
Realistic, but
concomitant lack of
control over lifestyle etc.
Graham et al, 1996
Study 1
60 Hz, 1 or 20 µT
intermittent fields
Circularly polarised
8 hours:
11 men, sham
11 men, 1 µT
11 men, 20 µT
33 male volunteers.
Night-time serum
melatonin levels
No overall effect but
significantly grater
suppression in low
melatonin subjects.
-
Study 2
60 Hz, 20 µT
intermittent fields
Circularly polarised
8 hours:
1 night exposed
1 night sham
40 volunteers.
Night-time serum
melatonin levels.
No detected effect: possible
effect on low melatonin
subjects not replicated
Selmaoui et al,
1996
50 Hz, 10 µT
continuous or intermittent
fields
Linearly polarised
9 hours:
1 night continuous
1 night intermittent
Control group none
32 volunteers.
Night-time serum
melatonin levels and
excretion of its major
urinary metabolite
No detected effect: a small
non-significant shift in the
onset of increased
nocturnal melatonin
-
Graham et al, 1997
60 Hz, 20 µT
continuous fields
Circularly polarised
8 hours:
1 night exposed
1 night sham
40 young male volunteers.
Night-time serum
melatonin levels
No overall effect
-
Wood et al, 1998
50 Hz, 20 µT
intermittent fields
Sinusoidal or square
wave
2 Friday nights:
1 night exposed
1 night sham
30 adult male volunteers.
Night-time serum
melatonin levels
Possible delay and
reduction of night-time
melatonin levels in
subgroup
Inconsistent, variable
data: incomplete
volunteer participation
Graham et al, 2000
60 Hz, 20 µT
intermittent fields
Circularly polarised
8 hours per night:
4 consecutive nights
30 young male volunteers.
Early morning excretion of
urinary melatonin and its
metabolite
Reduced consistency in
night time melatonin in
exposed group
Some suggestion that
stability of melatonin
measurements over time
may be influenced by
magnetic fields
Melatonin and magnetic fields
II – chronic exposures in human populations
• However, for chronic exposures, there are now at least 11 studies in human
populations showing that magnetic fields as low as 0.2 µT suppress or
otherwise disrupt the nocturnal production of melatonin in the pineal gland
• While in some studies the effect is weak, in others a clear reduction is
observed including a dose-response effect
Human population studies of the suppression of Melatonin by power frequency magnetic fields
•
•
•
•
•
•
•
•
•
•
•
•
Wilson, B.W., Wright, C.W., Morris, J.E., Buschbom, R.L., Brown, D.P., Miller, D.L., Sommers-Flannigan, R. and Anderson, L.E.,
1990. Evidence for an Effect of ELF Electromagnetic Fields on Human Pineal Gland Function. Journal of Pineal Research, 9, 259-269.
Pfluger, D.H. and Minder, C.E., 1996. Effects of exposure to 16.7 Hz magnetic fields on urinary 6-hydroxymelatonin sulfate excretion
of Swiss railway workers. Journal of Pineal Research, 21, 91-100.
Burch, J.B., Reif, J.S., Yost, M.G., Keefe, T.J. and Pitrat, C.A., 1998. Nocturnal excretion of a urinary melatonin metabolite among
electric utility workers. Scand. J. Work Environ. Health, 24(3), 183-189.
Burch, J. B., Reif, J. S., Yost, M. G., Keefe, T. J. and Pitrat, C. A., 1999. Reduced excretion of a melatonin metabolite in workers
exposed to 60 Hz magnetic fields. American Journal of Epidemiology, 150, 27-36.
Davis, S., Kaune, W.T., Mirick, D.K., Chen, C. and Stevens, R.G., 2001. Residential Magnetic Fields, Light-at-Night, and Nocturnal
Urinary 6-Sulfatoxymelatonin Concentration in Women. American Journal of Epidemiology, 154 (7), 591-600.
Levallois, P., Dumont, M., Touitou, Y., Gingras, S., Mâsse, B., Gauvin, D., Kröger, E., Bourdages, M. and Douville, P., 2001. Effects of
Electric and Magnetic Fields from High-power Lines on Female Urinary Excretion of 6-Sulfatoxymelatonin. American Journal of
Epidemiology, 154 (7), 601-609.
Burch, J. B., Reif, J. S., Noonan, C. W. and Yost, M. G., 2000. Melatonin metabolite levels in workers exposed to 60 Hz magnetic
fields: Work in substations and with 3-phase conductors. Journal of Occupational and Environmental Medicine, 42(2), 136-142.
Juutilainen, J., Stevens, R. G., Anderson, L. E., Hansen, N. H., Kilpeläinen, M., Kumlin, T., Laitinen, J. T., Sobel, E. and Wilson, B. W.,
2000. Nocturnal 6-hydroxymelatonin sulfate excretion in female workers exposed to magnetic fields. Journal of Pineal Research, 28,
97-104.
Burch, J. B., Reif, J. S., Noonan, C. W., Ichinose, T., Bachand, A. M., Koleber, T. L. and Yost, M. G., 2002. Melatonin metabolite
excretion among cellular telephone users. International Journal of Radiation Biology, 78, 1029-1036. (Note that although the title of
this paper concerns cellular phone users, the authors also report a reduction in melatonin metabolite excretion in relation to exposure to
60 Hz magnetic fields)
Graham, C., Cook, M. R., Sastre, A., Riffle, D. W., and Gerkovich, M. M., 2000. Multi-night exposure to 60 Hz magnetic fields: Effects
on melatonin and its enzymatic metabolite. Journal of Pineal Research, 28, 1-8.
Wood, A. W., Armstrong, S. M., Sait, M. L., Devine, L. and Martin, M. J., 1998. Changes in human plasma melatonin profiles in
response to 50 Hz magnetic field exposure. Journal of Pineal Research, 25, 116-127.
Touitou, Y., Lambrozo, J., Camus, F. and Charbuy, H., 2003, Magnetic fields and the melatonin hypothesis: a study of workers
chronically exposed to 50-Hz magnetic fields. Am J Physiol Regul Integr Comp Physiol, 284: R1529-R1535.
Human population studies on effects of magnetic fields on pineal melatonin production (page 1 of 3)
Authors
No. of cases/controls
Type of EMF
Location
Time of Year
Key Results
Wilson et al.
(1990)
42: 32 women; 10 men
(volunteers acted as own
controls)
Electric blankets
(AC compared
with DC)
Washington
State USA
Around winter
solstice
No overall effect but 7 individuals using
AC (50% higher MF) saw a sig. decrease
in their levels during the study period.
Pfluger et al.
(1996)
108 men
66 engineers
42 controls (train attendants &
station managers with average
exposure over 1 µT)
Both groups work shifts
Railway
employees
Switzerland
Early Autumn
1993
Lowered daytime levels (factor of 0.81)
in engineers compared to controls but no
difference in nocturnal levels. Evidence
of a rebound of levels during leisure
days.
Burch et al.
(1988)
142 men 20-60 yrs, mean age
41 yrs
29 generation workers
56 distribution workers
57 controls (utility
maintenance & admin. staff)
Electric Utility
Workers
Colorado USA
Wood et al.
(1998)
30 adult males 18-49 yrs
Laboratory
generated,
circularly
polarized, 50Hz
magnetic field
Melbourne,
Australia.
Association between residential MF
exposure and lower nocturnal levels.
Modest reductions in levels after work
MF exposure. Greatest reductions in
levels when work and home exposures
combined.
February –
September
over a two
year period
(1994-1996)
Evidence that exposure to MF during a
certain time window cause a phase delay
in the onset of nightly melatonin
secretion (and some evidence of a
reduction in maximum melatonin level)
Human population studies on effects of magnetic fields on pineal melatonin production (page 2 of 3)
Burch et al.
(1999)
142 men as in Burch et al.
1988
Electric Utility
Workers
Colorado USA
One year
period
Reduction in levels on the second and
third days of occupational exposure to
MF (effect modified by light exposure).
Negligible MF effects in subjects with
high light exposure.
Burch et al.
(2000)
149 men mean age 44 yrs
50 generation workers
60 distribution workers
39 controls (utility
maintenance & admin. staff)
Substations (3
phase – circularly
polarized)
Colorado,
USA
January September
No effect due to 1-phase exposure.
Reduction found due to exposure >2hrs
to 3-phase.
Juutilainen et
al. (2000)
60 female
Mean age 44.1 yrs (workers)
& 43.1 yrs
(controls) 39 garment workers
(8 of which did not operate
machines but were ‘possibly
exposed’)
21 controls.
Sewing machine
workers.
.
Kuopio,
Finland.
3 week period
around spring
equinox
No week /weekend variations, but lower
levels in workers compared to controls
Graham et al.
(2000)
30 men 18 –35 yrs
Mean age 22 yrs
(volunteers acted as own
controls)
Laboratory
generated,
circularly
polarized, 60Hz
magnetic field
Missouri, USA
Spring and
summer
No statistically significant effect.
Suggestion of reduction due to chronic
exposure.
Davis et al.
(2001)
203 women
20-70 yrs
(Night time)
Residential 60 Hz
magnetic fields
Washington
State USA
14 month
period
Higher bedroom MF associated with
lower levels during the same night
(association strongest with lighter nights)
Human population studies on effects of magnetic fields on pineal melatonin production (page 3 of 3)
Levallois et
al.
(2001)
221 women subjects and 195
women controls
Mean age 45.5 yrs (subjects) &
45.8 yrs (controls)
735 kV Power
Lines
Quebec City
Canada.
Decrease in melatonin levels in relation
to age and body mass index, more
pronounced in women living near the
powerlines.
Burch et al.
(2002)
study 1: 149 (as in Burch et al.
2000)
study 2: 77
22 generation workers
29 distribution workers
23 controls
Cell telephone use
in electric utility
workers
Colorado,
USA
Study 1 – no effect.
Study 2 – exposure-related reductions
where use >25 mins (may be enhanced
by MF exposure)
Touitou et al
(2002).
15 men 31.5- 46 yrs. Mean age
38.0 yrs (exposed) exposures
0.1-2.6 µT
15 controls 34.5 – 47 yrs.
Mean age 39.4 yrs
exposures 0.004-0.092 µT
Chronically
exposed workers
who work in extra
high voltage
substations and
also live near the
substations
Paris, France
Autumn
No differences in nocturnal plasma
melatonin or the melatonin metabolite
between the workers and controls.
Geomagnetic
Burch et al.
(1999)
132 men
Geomagnetic
disturbances in
conjunction with
60Hz MF in
electric utility
workers
Colorado,
USA
March ’95 –
March ‘96
Lower levels on days with high
geomagnetic activity. Effect enhanced
when activity combined with high MF or
low light levels.
Inhibition of the action of melatonin
•
Experiments in vitro have shown that magnetic fields as low as 1.2 µT inhibit
the ability of melatonin to suppress the growth of MCF-7 breast cancer cells at
physiologically melatonin concentrations 10-11 to 10-9 molar (Ishido et al. 2001
and four other independent studies)
•
Magnetic fields as low as 1.2 µT also suppress the anti-proliferative action
Tamoxifen (Harland & Liburdy 1997, Harland et al. 1999, Blackman et al.
2001)
•
Reiter (1998) pointed out that the role of the retina in coupling magnetic fields
to the pineal was unproven. He pointed out that while it was assumed that
melatonin synthesis is suppressed by magnetic fields, the reduction in serum
melatonin could be a result of an increased uptake and utilisation as a free
radical scavenger
letters to nature (Vol. 429, 177-180, 2004)
Resonance effects indicate a radical-pair mechanism for avian magnetic compass
Tborslen Ritzl, Peter Tbalau2, John B. Philllps3, Roswilha Wiltschko2 & Wolfgang WiJtschko2
1 Department Df Physics and AstronDmy, University Df CalifDrnia. 1rvine, California 92697-4575, USA
2ZoDlogisches 1nstitut, Pachbereich BiolDgie und 1nformatik,
J. W. GDethe- Universitiit, Siesmayerstrasse 70, D-60054 Frankfurt am Main, Germany
3Department Df BiDlDgy, 2119 Derring Hall, Virginia Tech, Blacksburg, Virginia 24061, USA
Migratory birds are known to use the geomagnetic field as a source of compass information. There are two competing
hypotheses for the primary process underlying the avian magnetic compass, one involving magnetite, the other a
magnetically sensitive chemical reaction. Here we show that oscillating magnetic fields disrupt the magnetic orientation
behaviour of migratory birds. Robins were disoriented when exposed to a vertically aligned broadband (O.I – IO MHz)
or a single-frequency (7-MHz) field in addition to the geomagnetic field. Moreover, in the 7-MHz oscillating field, this
effect depended on the angle between the oscillating and the geomagnetic fields. The birds exhibited seasonally
appropriate migratory orientation when the oscillating field was parallel to the geomagnetic field, but were disoriented
when it was presented at a 240 or 48° angle. These results are consistent with a resonance effect on singlet-triplet
transitions and suggest a magnetic compass based on a radical pair mechanism.
The magnetic compass of birds is light-dependent, and exhi-bits strong lateralization with input coming primarily from the right
eye. However, the primary biophysical process underlying this compass remains unexplained. Magnetite as well as biochemical
radical-pair reactions have been hypothesized to mediate sensitivity to Earth-strength magnetic fields through fundamentally
different physical mechanisms. In the magnetite-based mechanism, magnetic fields exert mechanical forces3. In the radical-pair
mecha-nism, the magnetic field alters the dynamics of transitions between spin states, after the creation of a radical pair through
a light-induced electron transfer. These transitions in turn affect reaction rates and products. Although in most radical-pair
reactions the effects of Earth-strength magnetic fields are masked by stochastic fluctuations, model calculations show that such
effects can be amplified beyond the level of stochastic fluctuations in specialized radical-pair receptor systems.
Exploiting the principles of magnetic resonance, we developed a diagnostic tool to identify a radical-pair process as the primary
process for a physiological magnetic compass. No change in magnetic alignment of magnetite receptors is expected for weak
oscillating fields with frequencies larger than 100kHz (ref. 14).
Testing the hypotheses
•
More carefully designed studies of pineal melatonin disruption in human
populations chronically exposed to ELF (and indeed RF) magnetic fields/EMF
•
Special attention should be given to polarised fields
•
Studies of the protectiveness of melatonin on haemopoietic stem cells in vivo
in the presence of ELF magnetic fields – cf the experiments of Ishido et al.
(2001) and others
•
Studies of the effects of melatonin disruption on human fetal development
•
Does melatonin disruption affect the risk of miscarriage?
Summary
•
Hypothesis: Exposure to ELF magnetic fields increases the risk of
childhood leukaemia via melatonin disruption
•
If this hypothesis is correct this would also implicate light-at-night as a
causal factor in childhood leukaemia
•
This would help to explain the increasing incidence of childhood
leukaemia in possibly a major way, given the ubiquitous nature and
rate of increase in light-at-night
•
However, apart from childhood leukaemia, melatonin could be a
common factor in the various apparently disparate adverse health
outcomes associated with EMF exposures: adult brain cancer, ALS and
miscarriage and possibly adult leukaemia, depression and suicide
(California Health Dept EMF Report, June 2002)
Acknowledgements
The research at Bristol University
is supported by
CHILDREN with LEUKAEMIA
and the Department of Health