Children's EMF Research Agenda
http://www.who.int/peh-emf/research/children/en/index.html

Introduction & general comments
The Working Group considered research recommendations for studies relevant to the risk ofadverse health effects in children from exposure to electromagnetic fields (EMFs). The issues
under consideration reflected and amplified the various suggestions and proposals made by theindividual presenters at the preceding WHO Workshop on Childhood Sensitivity to EMFs held in
Istanbul on 9 & 10 June 2004. The workshop proceedings are available in a special edition of
Bioelectromagnetics (in press).
Particular issues included the role of extremely low frequency (ELF) magnetic fields in thedevelopment of childhood cancer and possible risks from mobile phone radiofrequency (RF)radiation, especially regarding brain cancer and cognitive function. Less emphasis was given torisks from exposure to static fields and to fields associated with security devices. However,pregnant workers are employed in retail industries with an increasing prevalence of security andidentity devices, including devices for electronic article surveillance (RFID/EAS). A better
understanding of the dosimetry and possible health effects for this region of the spectrum isneeded, since it is not clear that extrapolation from higher and lower frequency regions issufficient.
Separate breakout groups considered research recommendations for further epidemiologicalstudies, laboratory studies (including those using volunteers, animals and in vitro techniques), anddosimetry work which were then discussed in a plenary session. The relevance of these different
studies to health risks in people varies. Epidemiological studies of the distribution of disease inpopulations and the factors that influence this distribution provide direct information on the healthof people exposed to an agent and are given the highest weighting. However, they may be affectedby bias and confounding, and their observational nature makes it difficult to infer causal
relationships, except when the evidence is strong. Experimental studies using volunteers can givevaluable insight into the transient physiological effects of acute exposure, although for ethicalreasons these studies are normally restricted to healthy people. Recommendations concerning
laboratory studies using children are, of course, subject to appropriate ethical approval. Studies of1

animals, tissues and cell cultures are also important but are given less weight. Animal studies canoften be expected to provide qualitative information regarding potential health outcomes, but thedata may not be extrapolated to provide quantitative estimates of risk, largely because ofdifferences between species. Studies carried out at the cellular level are normally used toinvestigate mechanisms of interaction, but are not generally taken alone as evidence of effects invivo. Nevertheless, each type of study has a role to play in determining the scientific plausibility ofany potential health risk.
Dosimetry provides a precise measure of the interaction of EMFs with people, and exposure
assessment provides an estimate of individual and population exposure to EMFs that contributes
to the assessment of the likely impact of exposure on health. Each such assessment needs toconsider all sources of EMF (low and high frequencies) to which an individual or a population may
be exposed.

General recommendations
The Dosimetry Working Group made the following general recommendations:•

A better understanding of foetal and childhood exposure to EMFs is required, including anassessment of exposure to the high static magnetic fields encountered around magnetic
resonance imaging (MRI) equipment and the lower static magnetic fields encountered inpublic transport vehicles, and an assessment of exposure to ELF fields, especiallyresidential exposure from under-floor electrical heating and from transformers inapartment buildings. For RF fields, exposure assessment is particularly weak for basestations and TV and radio towers and needs further exploration. High Priority

Rationale: This information, in combination with dosimetric modelling and an understandingof possible biological effects, is needed to assess the risk to health posed by such
exposure.
•

More-accurate dosimetric models of pregnant women, of foetuses at various
developmental stages (neural tube closure; differentiation and organogenesis; growth) andof children are needed. In addition, an exploration of EMF microdosimetry at the cellular orsubcellular levels should be supported. High Priority

Rationale: Dosimetric information regarding pregnancy and the developing foetus is lacking;this information is required for a proper health risk assessment. In addition, exploration of
EMF microdosimetry may yield new insights concerning biologically relevant targets.

2•Additional data on the dielectric and thermal properties of human tissues and organs at
various developmental stages, including the foetal stage, is needed. High Priority

Rationale: The dielectric constant is a factor that varies with age. Foetal data could besignificantly different from data on children or adults, but it may be very difficult to obtain
ethical approval to acquire experimental data. Perhaps ultrasonic examinations could
provide data on dimensions that may allow estimation of water content, from which
dielectric constants can be derived.

Static fields
Static magnetic fields were not specifically addressed at the Workshop. It was recognized, however,that there is also a need to address childhood susceptibility to static magnetic fields because ofboth developing technologies like magnetic levitation transportation and the ever-increasing use ofmagnetic resonance imaging techniques. This led to the following recommendation:•

Future laboratory studies of static magnetic fields should consider the effects of prenatal
and early postnatal exposures in addition to those of adult exposure. High Priority

Rationale: There are few studies of the effects of prenatal and early postnatal exposure,particularly to very intense magnetic fields (>1 T).

Extremely Low Frequency Fields
1. Epidemiological Studies
Something of an impasse has been reached in designing studies of ELF magnetic fields andchildhood leukaemia. While existing epidemiological studies show a consistent association, most of
the available studies are of case-control design and are thus potentially subject to selection bias.
To move forward we need innovative approaches, which might include (1) designing studies capableof evaluateing selection bias (e.g., by collecting data on magnetic fields and participation) and/or
minimizing it (e.g., a cohort study), or (2) identifying large, highly exposed populations (e.g., thoseliving in apartments next to transformers), or susceptible subgroups (e.g., previously initiatedpopulations in which magnetic fields act as a second ‘event’ in carcinogenesis). In addition, twohypotheses concerning causality (contact current and melatonin) were discussed at the Workshop.
All of these approaches and hypotheses pose major challenges.
•

Pooled analysis of childhood cancer studies. High Priority
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Rationale: Pooled analyses of childhood leukaemia studies have been very informative.
Although new studies would not fundamentally change the results of the previous pooled
analyses, recent studies will add new countries and enough data to probe the results
further. It might be possible to further explore the high end of the dose-response curve.
Additionally, risk modifiers - for example, age - might be further explored. Brain cancer
studies have shown inconsistent results; a pooled analysis of brain cancer studies may also
be very informative, may inexpensively provide insight into existing data, including thepossibility of selection bias, and, if appropriate (i.e., if studies are sufficiently homogeneous),
may come up with the best estimate of risk.
•

Further studies of ELF exposure and miscarriage. Medium Priority

Rationale: Two recent California studies have reported an increased risk of miscarriage due
to maximum levels of ELF exposure, but the studies have areas of potential weakness instudy design that can be improved. First we recommend studies to identify behavioural
determinants of maximum fields. Further investigation, focusing on early pregnancy loss andusing improved design, would also contribute to this area.
2. Volunteer studies
These recommendations address effects for which there is some supporting evidence in studies
using adults.
•

Laboratory-based studies of cognition and changes in electroencephalograms (EEGs) inchildren exposed to ELF fields in the laboratory, if ethical approval is possible. High Priority

Rationale: Studies of adult volunteers and animals suggest that acute cognitive effects may
occur with short-term exposures to intense fields. Such effects are very important for thedevelopment of exposure guidance (e.g., McKinlay et al., 2004; WHO ELF Research Agenda)
but there is a lack of specific data concerning field-dependent effects in children.
3. Animal studies
These recommendations focus on possible carcinogenic effects, particularly in relation tochildhood leukaemia, and effects in key tissues and organs regarded as potentially susceptible to
EMFs, particularly the developing central nervous system (CNS), haemopoietic (bone marrow)tissue and immune system. Experimental protocols should include prenatal and/or early postnatal
exposure to EMFs.

4•

Further development and experimental investigation using appropriate animal models,
including the use of transgenic animals (e.g., Carron et al., 2000), which develop a disease
having similarities to childhood acute lymphoblastic leukaemia. (Animal studies carried out
to date have not used such models.) Experimental studies to include the effects of prenatal
exposure and the combined effects of ELFs and known carcinogens. High Priority

Rationale: The possible role of EMF exposure in childhood leukaemia development is apriority research area (e.g., AGNIR, 2001; WHO ELF Research Agenda). In addition the
combined effects of ELF-EMFs and known chemical or physical carcinogens and/or
mutagens have been reported in many studies (IARC, 2002).
•

Studies of developmental effects of pre- and postnatal exposure to low-frequency EMFs
on immune function and on the induction of minor skeletal variations. Effects of prolonged,
intermittent exposure from the early postnatal period on subsequent cognitive function in
animals. Medium Priority

Rationale: An increase in minor skeletal anomalies is the only consistent finding from anumber of developmental EMF studies in mammals (e..,g Juutilainen, 2003). The immune
system continues to develop postnatally; Study of the effects of ELF fields on this systemis thus a useful means to evaluate them as possible immunotoxicants. Behavioural studies
with immature animals provide a useful and established model for studying possible
cognitive effects in children.
•

Further study of possible ELF carcinogenic mechanisms, including exposure to intermittent
fields and transients, both alone and in combination with known carcinogens. Low Priority

Rationale: The possible carcinogenicity of EMFs remains an issue of concern (e.g., IARC,
2002), although the experimental evidence for carcinogenic effects is weak. However,hypotheses such as those involving the role of signal intermittence, transients or contact
currents have not been widely investigated and the possibility for co-carcinogenicity must
be clarified.
4. In vitro studies
Areas requiring further ELF in vitro study include possible electric field and (contact) current
effects on carcinogenic processes, especially pathways involved in haemopoietic celldifferentiation and proliferation, and on nerve cell growth and synaptogenesis. In addition, further
exploration of the possible role of melatonin in free-radical scavenging is required.

5•Studies of ELF magnetic field and induced electric field effects on cell differentiation (e.g.,during haemopoiesis in bone marrow) and on nerve cell growth using brain slices or cultured
neurons. High Priority

Rationale: As in the recommended animal studies, possible effects on pre- and post-natal
cellular differentiation and tissue development are a priority research area. Cell
differentiation is inhibited during neoplastic progression; cell orientation and migration areboth key processes in development. The developing nervous system and bone marrow arethought to be key tissues in this respect.
•

Effect of EMF exposure on the protectiveness of physiological levels of melatonin against
oxidative damage from free radicals, reactive oxygen species, etc. during haemopoiesis in
foetal and postnatal tissue. Medium Priority

Rationale: Melatonin has been shown to be highly protective against oxidative damage tohuman lymphocytes in vitro (e.g., Vijayalaxami et al., 1996, 2004) and similar damage to thebrain tissue of rat foetuses in vivo (Wakatsuki et al., 1999, 2001), possibly by increasing theconcentration of known radical scavengers such as superoxidase dismutase (Okatani et al.,2000). The possibility that EMF exposure may affect the ability of melatonin to suppress
oxidative damage in foetal or postnatal tissue should be investigated.
•

Further studies of possible carcinogenic mechanisms for ELF fields, particularly in
combination with known carcinogens. Low Priority

Rationale: The possible carcinogenicity of EMFs remains an issue of concern (e.g., IARC,
2002), although the experimental evidence for carcinogenic effects is weak. The combined
effects of ELF-EMFs and known chemical or physical carcinogens and/or mutagens havebeen reported in many studies (IARC, 2002). In addition, hypotheses such as those involving
the possible role of signal intermittence or transients have not been studied.
5. Dosimetry and exposure assessment
A better understanding of the prevalence of earth leakage currents and the potential
consequences of exposure to contact currents in small children (e.g., when bathing), is needed.
Work is in progress to examine the prevalence of contact currents in countries other than the
United States (e.g., in European and Asian residential electrical systems). If exposure to contact
currents is a global issue and some mechanism can be demonstrated, the model should be further
examined.

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•Dosimetric modelling of the interaction between induced or injected current and juvenile
limbs should be undertaken, taking account of reduced surface resistance, lack of bone
calcification and the presence of active marrow. High Priority

Rationale: The extent to which electric current flows through the bone marrow of smallchildren as a consequence of contact which allows an earth leakage current to flow throughtheir bodies should be further studied.
•

Assess exposure to the 217-Hz nonsinusoidal magnetic fields from mobile phones. Low
Priority

Rationale: The pulsating battery current in a mobile phone generates a low-frequency
nonsinusoidal magnetic field (Jokela 2004) in the vicinity of the phone. The field penetrates
without any effect on the skin into tissue. Some preliminary estimates show that theresulting exposure to induced currents in the head is not much lower than the ICNIRP limit.
Furthermore, it has been suggested that mobile phones are an important source of ELF
exposure, particularly to bone marrow in children’s hands. More detailed investigation of
exposure is necessary to assess exposure quantitatively

Radio Frequency Fields
1. Epidemiological studies
There is little relevant epidemiology at present that examines health effects in children; thefollowing recommendations address general health effects, including cancers in children who use
mobile phones or live near base stations or radio or TV towers.
•

Prospective cohort study of children mobile phone users and all health outcomes otherthan brain cancer (see below) but including more general health outcomes such as
cognitive effects and effects on sleep quality. High Priority

Rationale: Since many children are heavy mobile phone users and will continue to be in the
future, they represent a unique population. The type of mobile use among children (e.g. text
messaging), their potential biologic vulnerability and longer lifetime exposure make such a
study desirable. Cognitive effects and other general health outcomes have been
anecdotally reported in mobile phone users. They can be assessed in a prospective cohort
study of children. A separate study of children was found necessary, as it is not possible tojust extend the age range of a cohort study of adults because the outcomes have to beassessed by different methods in children and adults, and children’s exposure probably
7differs from that of adults’ (more use of pay-as-you-go SIM-cards, more frequent changeof phones and operator).
•

Case-control study of children mobile phone users and brain cancer. High Priority

Rationale: Brain cancer is an important end-point to study given the location of theantenna for the phone, but it is rare in children and so this is not likely to be a feasible
end-point for a cohort study.
•

Nested case control studies of childhood cancer with improved exposure assessment for(1) base stations and (2) TV and radio towers. High Priority

Rationale: There is at present a lack of information concerning health effects associatedwith living in close proximity to base stations or TV or radio towers. One particular difficultyis exposure assessment. Further investigation into improved measures is a critical step inbetter capturing exposure from these sources and in determining the feasibility of
epidemiological studies of children living in the vicinity of these sources.
2. Volunteer studies
The following recommendations address effects seen in laboratory-based studies using adultvolunteers.
•

A laboratory-based assessment of effects of RF exposure on cognition, EEGs, and sleep inchildren is recommended as a part of a larger prospective cohort study (see theEpidemiology section). If ethical approval can be obtained, acute effects on cognition andEEGs should also be investigated in children exposed to RF fields in the laboratory. HighPriority

Rationale: Cognitive effects are a priority research area in RF studies. However there is a
paucity of data concerning RF effects on children (Goldstein et al, 2003; AGNIR, 2003; WHO
RF Research Agenda).
3. Animal studies
A large U.S. National Toxicology Program (NTP) rodent (both rats and mice) study is likely to be
funded in the near future. The study will examine the toxicity and carcinogenicity of RF radiation
characteristic of mobile phones; animals will be exposed in utero and postnatally. A full
histopathology will be carried out, along with assays of endocrine levels, estrus cycling and spermlevels, urinary metabolite patterns (as indicators of physiological perturbation), haematology and8genotoxicity (i.e., micronucleus frequency, DNA-strand breaks, etc.). There will be a particularfocus on changes in blood-brain-barrier permeability and any concomitant neuropathology. [Tissue
may be made available to other research groups; contact Ron Melnick, email:melnickr@niehs.nih.gov]
The recommendations given below focus on the developing central nervous system, haemopoietic(bone marrow) tissue and immune system. Experimental protocols should include prenatal and/or
early postnatal exposure to EMFs.
•

Studies investigating the effects of prolonged exposure of immature animals to RF fields onthe development and maturation of the CNS, using behavioural, morphological (e.g., synapse
formation) and molecular (e.g., using gene microarrays) endpoints. High Priority

Rationale: Possible RF effects on children were specifically raised by the UK’s Independent
Expert Group on Mobile Telephones (IEGMP, 2000); the CNS was considered potentially
one of the most susceptible of the various organs and tissues that continue to develop
during childhood.
•

Effects of prenatal exposure to RF fields on the development and maturation of theblood-brain barrier. [Note that funded work is likely to begin on this topic in the near future;
see above.] High Priority

Rationale: Possible effects on the adult blood-brain barrier and the potential for resulting
neuropathology have long been a controversial issue in RF research (e.g., IEGMP, 2000;
WHO RF Research Agenda). These studies should be extended to cover pre- and postnatal
development of the blood-brain barrier. (In humans, this development is complete at
approximately 6 months [Rodier, 2004].)•

Studies investigating the effects of prolonged exposure of immature animals to RF fields onthe development of the immune system, including microglia cells (resident macrophages)
and induction of autoimmunity in the brain. Medium Priority

Rationale: The immune system also develops during early childhood and is a critical tissue
with regard to possible effects of RF exposure. Studies performed in the former USSR
showed induction of autoimmunity after exposure to RF fields (Vinogradov, 1993).
4. In vitro studies
Studies of possible RF effects on carcinogenic processes, particularly effects on differentiation
pathways and haemopoietic tissue, continue to be of interest. In addition, effects on nerve cell9

growth and synaptogenesis are considered worthy of further research. The possibility that
biological tissue can somehow demodulate modulated RF signals to produce biologically significant
ELF electric fields and currents has long been a controversial area. Research into this area, basedon a recently proposed, very sensitive method of detection, is being funded in the UK (Challis, inpress). If real, this effect could have important implications for both childhood and adult exposure.
Other mechanistic studies were also recommended.
•

Studies of RF effects on cell differentiation, e.g., during haemopoiesis in bone marrow, andon nerve cell growth using brain slices/cultured neurons. High Priority

Rationale: Cancer cells are generally locked into a rapidly dividing and relatively
undifferentiated state, and the possibility that haemopoietic and/or neuronal tissue showsa growth response to EMF exposure was considered to be an important area for further
investigation.
•

Continued studies of possible mechanisms of RF interaction. Medium Priority

Rationale: Research hypotheses based on plausible interaction mechanisms are a key partof the design and execution of animal and epidemiological studies carried out in order toevaluate possible risks to health. There are two hypotheses that are worthy of further
investigation (Challis, this issue): (1.) Whether the mechanism leading to an increase in
free-radical concentrations that has been demonstrated at frequencies below 80 MHz
might also apply at higher frequencies. 2. Whether the above-average temperature risesthat might be expected to occur in electrically conducting regions within thermallyinsulated parts of the body, such as the cochlea and vestibular apparatus, are large enoughto cause concern.
5. Dosimetry and exposure assessment
A key issue in this area has been the development of a personal dosimeter in order to greatly
improve exposure assessment (for example, around base stations) for epidemiological studies(Wiart, in press). Recommendations were made for improved childhood exposure assessment anddosimetric and thermal modelling.
•

Research is needed to document rapidly changing patterns of phone use (SMS, email,classical phone communication, etc.) and exposure of different parts of the body forchildren and foetuses. High Priority

Rationale: This research would be required to complement epidemiological studies.
10Exposure surveys (in contrast to simple source evaluations) to assess children’s exposure
are lacking, but urgently needed. Service providers are important sources of information
regarding exposure and should be encouraged to participate in exposure surveys andepidemiological studies.
•

Dosimetric models of RF energy deposition in children and foetuses, combined withappropriate models of human (childhood) thermoregulatory responses, should be developed.
High Priority

Rationale: These dosimetric and thermoregulatory models are required in order to predict
potential hazards associated with specific RF exposure conditions (Goldstein et al., 2003;
WHO RF Research Agenda). Dosimetric calculations and realistic modelling of exposure to
the foetus under various exposure scenarios (e.g., with and without a hands-free device)
are needed.

References
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AGNIR (2001). ELF Electromagnetic Fields and the Risk of Cancer. Report of and Advisory
Group on Non-Ionising Radiation. Docs NRPB, 12(1). Chilton NRPB.
AGNIR (2003). Health Effects from Radiofrequency Electromagnetic Fields. Report of andAdvisory Group on Non-Ionising Radiation. Docs NRPB, 14(2). Chilton NRPB.
Carron C, Cormier F and Janin A et al. 2000. TEL-JAK2 transgenic mice develop T-cellleukaemia. Blood, 95(12), 3891-3899.
IARC (2002). Non-ionizing Radiation, Part 1: Static and Extremely Low-Frequency (ELF)
Electric and Magnetic Fields. IARC Monographs on the Carcinogenic Risks to Humans.
Volume 80. Lyon, IARC Press.
IEGMP, 2000. Mobile Phones and Health. Report of an Independent Expert Group on Mobile
Phones (Chairman: Sir William Stewart). Chilton, NRPB.
Juutilainen J. (2003). Developmental effects of extremely low frequency electric andmagnetic fields. In: Proceedings of an International Workshop, NRPB, Chilton UK. March
24-25, 2003. Radiat Prot Dosim., 106(4), 385-390.
McKinlay A F, Allen S G, Cox R, Dimbylow P J, Mann S M, Muirhead C R, Saunders R D,
Sienkiewicz Z J, Stather J W, and Wainwright P R., 2004. Review of the Scientific Evidence
for Limiting Exposure to Electromagnetic Fields (0-300 GHz). Docs NRPB, 15(3), Chilton,
NRPB.
Okatani Y., Wakatsuki A., and Kaneda, C., 2000. Melatonin increases activities of glutathione
peroxidase and superoxide dismutase in foetal rat brain. J Pineal Res, 28, 89-96.
Rodier, P. 2004. Environmental causes of central nervous system maldevelopment.
Pediatrics, 113(4), 1076-1083.
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Vijayalaxmi., Reiter, R. J., Herman, T. S. and Meltz, M. L. 1996. Melatonin andradioprotection from genetic damage: In vivo/in vitro studies with human volunteers.
Mutation Research, 371, 221 -228.
Vijayalaxmi, Reiter, R. J. Tan, DX., Herman, T. S., Thomas, C. R., 2004, Melatonin as aradioprotective agent: a review. International Journal of Radiation Oncology, Biology,
Physics, 59, 639-653.
Vinogradov G. 1993. The phenomenon of autoimmunity from the effects of non-ionizing
microwave radiation. In “Electricity and Magnetism in Biology and Medicine”, M. Blank, ed.,San Francisco Press, Inc., 649-650.
Wakatsuki A., Okatani, Y., Izumiya, C., and Ikenoue, N., 1999. Melatonin protects against
ischemia and reperfusion-induced oxidative lipid and DNA damage in foetal rat brain. J
Pineal Res, 26,147-152.
Wakatsuki A., Okatani, Y., Shinohara, K., Ikenoue, N., Kaneda, C. and Fukaya, T., 2001.
Melatonin protects foetal rat brain against oxidative mitochondrial damage. J Pineal Res, 30,
22-28.
WHO ELF Research Agenda: http://www.who.int/peh-emf/research/agenda/en/
WHO RF Research Agenda: http://www.who.int/peh-emf/research/rf03/en/

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