Reviews of the science >
ICNIRP
ICNIRP
is the International Commission on Non-Ionizing Radiation Protection.
In 2001 their Standing Committee on Epidemiology
published a major Review of the Epidemiological Literature on EMF
and Health. See the complete abstract
Their conclusions on specific diseases were:
Childhood leukaemia
Adult leukaemia
Adult nervous system tumours
Adult breast cancer
Neurodegenerative disorders
Suicide and depression
Cardiovascular disease
Reproductive Effects
Childhood leukaemia:
"Following the original report by Wertheimer
and Leeper linking the three most common forms of childhood cancer
with a proxy measure of residential EMF (wire codes), more than
18 studies in nine countries have shown no convincing evidence
of a relationship between childhood leukaemia and residential
EMF exposures among children with estimated exposure levels under
0.2 µT. A 2-fold increase in relative risk of childhood
leukaemia, confined to a very tiny fraction of children (estimated
as 0.8% in one large pooled analysis) with residential EMF exposures
≥ 0.4 µT, is difficult to interpret in the absence
of a known biological mechanism or reproducible experimental support
of carcinogenesis. There is also some evidence to suggest that
selection bias may account for some of the increase in risk among
the proportion of children with high residential EMF exposure."
Adult leukaemia:
"Results from these studies have ranged
from null to rather strong positive associations, with relative
risks in the upper exposure categories above 2.0. Unfortunately,
there is not a clear pattern in which the better studies are more
or less likely to produce positive associations. In the aggregate,
assuming random error accounts for differences among studies,
the results are most consistent with a weak positive association,
with relative risks for the more highly exposed groups of the
order of 1.1-1.3. Relative risks of this magnitude are below the
level at which epidemiological methods can effectively assess
causal relations. Nevertheless, the evidence at present supporting
a role for EMF in the etiology of adult leukemia is weak."
Adult nervous system
tumours:
"The conclusions provided for EMF and adult
leukemia are essentially applicable to the brain cancer literature
as well. A large number of studies, mostly addressing occupational
exposure, have generated measures of association ranging from
null to rather strongly positive, but in the aggregate, relative
risk estimates would be in the range of 1.1-1.3, a level at which
a meaningful discussion of causality is not possible."
Adult breast cancer
"The totality of evidence linking EMFs to
breast cancer, in men or women, remains weak."
Neurodegenerative
disorders
"For reasons discussed in the preceding
sections, the ALS [amyotrophic Lateral sclerosis] results are
intriguing and point toward a possible risk increase in subjects
with EMF exposure. However, confirmatory studies are needed, as
is an appropriate consideration of confounding, for example, from
electric shocks, as a conceivable explanation. As for AD [Alzheimer’s
disease], it appears the excess risk is constrained to studies
with weaker designs; thus support for the hypothesis of a link
between EMF and AD is weak."
Suicide and depression
"When assessing the overall literature on
EMF and suicide, it is necessary to consider the relative weights
of the available studies together with their results. In doing
so the original study must be given a relatively light weight
in relation to later studies because of methodological limitations.
Nevertheless, the latest study also suggests that an excess risk
may indeed exist.
The literature on depressive symptoms and EMF
is difficult to interpret because the findings are not consistent.
This complexity cannot easily be resolved by suggesting that one
type of result can be confined to a group of studies with methodological
problems or some other limitation."
Cardiovascular disease
"In summary, evidence of cardiovascular
effects due to elevated exposure to magnetic fields is weak, and
whether a specific association exists between exposure and altered
autonomic control of the heart remains speculative until corroborating
evidence from further large epidemiological studies becomes available."
Reproductive Effects
(note: this paper was written before the recent results from California)
"Thus fundamental methodological limitations
preclude firm conclusions about reproductive outcomes. Studies
with refined measurements of exposure and outcome could yield
different results than those reported to date. However, on the
basis of theoretical considerations and both experimental and
epidemiological studies, there is very little encouragement for
pursuing research on EMF and reproductive health. Existing evidence
does not support the hypothesis that maternal exposure to EMF
through residential, including heated bed, exposure or through
the workplace is associated with adverse pregnancy outcomes."
| Complete
Abstract
"Exposures to extremely low-frequency electric and
magnetic fields (EMF) emanating from the generation, transmission,
and use of electricity are a ubiquitous part of modern life.
Concern about potential adverse health effects was initially
brought to prominence by an epidemiologic report two decades
ago from Denver on childhood cancer. We reviewed the now
voluminous epidemiologic literature on EMF and risks of
chronic disease and conclude the following: a) The quality
of epidemiologic studies on this topic has improved over
time and several of the recent studies on childhood leukemia
and on cancer associated with occupational exposure are
close to the limit of what can realistically be achieved
in terms of size of study and methodological rigor. b) Exposure
assessment is a particular difficulty of EMF epidemiology,
in several respects: i) The exposure is imperceptible, ubiquitous,
has multiple sources, and can vary greatly over time and
short distances. ii) The exposure period of relevance is
before the date at which measurements can realistically
be obtained and of unknown duration and induction period.
iii) The appropriate exposure metric is not known and there
are no biological data from which to impute it. c) In the
absence of experimental evidence and given the methodological
uncertainties in the epidemiologic literature, there is
no chronic disease for which an etiological relation to
EMF can be regarded as established. d) There has been a
large body of high quality data for childhood cancer, and
also for adult leukemia and brain tumor in relation to occupational
exposure. Among all the outcomes evaluated in epidemiologic
studies of EMF, childhood leukemia in relation to postnatal
exposures above 0.4 µT is the one for which there
is most evidence of an association. The relative risk has
been estimated at 2.0 (95% confidence limit: 1.27-3.13)
in a large pooled analysis. This is unlikely to be due to
chance but, may be, in part, due to bias. This is difficult
to interpret in the absence of a known mechanism or reproducible
experimental support. In the large pooled analysis only
0.8% of all children were exposed above 0.4 µT. Further
studies need to be designed to test specific hypotheses
such as aspects of selection bias or exposure. On the basis
of epidemiologic findings, evidence shows an association
of amyotrophic lateral sclerosis with occupational EMF exposure
although confounding is a potential explanation. Breast
cancer, cardiovascular disease, and suicide and depression
remain unresolved. Key words: cancer, chronic disease, epidemiology,
extremely low-frequency EMF, review. -- Environ Health Perspect
109(suppl 6):911-933 (2001)."
http://ehpnet1.niehs.nih.gov/docs/2001/suppl-6/911-933ahlbom/abstract.html
|
back
|