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Electric and magnetic fields and health

index/glossary | EMFs At A Glance | EMF The Facts (pdf)
  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • EMF instruments and other commercial services
    • Adding fields together
    • Radiofrequencies
    • Screening EMFs
  • Sources
    • Overhead power lines
      • Fields from specific power lines
        • 400 kV
        • 400 kV – specific cases
        • 275 kV
        • 132 kV
        • 66 kV
        • 33 kV
        • 11 kV
        • 400 V/230 V
        • Replacing a 132 kV line with a 400 kV line
      • Summaries of fields from all power lines
      • Factors affecting the field from a power line
        • Voltage
        • Current
        • Clearance
        • Height above ground
        • Conductor bundle
        • Phasing
        • Balance between circuits
        • Balance within circuit
        • Ground resistivity
        • Two parallel lines
      • Calculating and measuring fields from power lines
        • Geometries of power lines
        • Raw data
        • On-line calculator
      • Fields from power lines – more detail on the physics
        • Field lines from a power line
        • The direction of the field from a power line
        • Power law variations in the field from a power line
      • Statistics of power line fields
    • Underground power cables
      • Different types of underground cable
      • Fields from cables in tunnels
      • Gas Insulated Lines (GIL)
      • Underground cables with multiple conductors
      • Effect of height on fields from underground cables
      • Screening fields from underground cables
    • Low-voltage distribution
      • UK distribution wiring
      • USA distribution wiring
    • House wiring
    • Substations
      • National Grid substations
        • Static Var Compensators
      • Sealing-end compounds
      • Distribution substations
      • Final distribution substations
        • Indoor substations
    • Transport
      • EMFs from electric trains (UK)
      • EMFs from cars
    • Appliances
    • Electricity meters
      • Smart meters
      • Traditional meters
    • Occupational exposures
      • Live-line work
      • Static Var Compensators
      • Occupational exposures on pylons
    • Field levels and exposures
      • Personal exposure
      • Other factors that vary with magnetic fields
      • Fields greater than 0.2 or 0.4 µT
      • Fields in different countries
      • How fields vary with time
    • Reducing your exposure
  • Known effects
    • Induced currents and fields
      • Numerical calculations of induced currents
      • Details of numerical calculations of induced currents and fields in the body
    • Effects of EMFs on equipment
    • EMFs and medical devices
      • Types of medical devices
      • Real-life experience of interference with Implanted Heart Devices
      • Laboratory Tests of Implanted Medical Devices
      • Consequences if interference does occur with an implanted heart device
      • Manufacturers of Implanted Heart Devices
      • Standards relating to pacemakers and other AIMDs
      • Interference with hearing aids and cochlear implants
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
    • EMFs, agriculture and the environment
      • Bees and microshocks
      • Behaviour of large mammals in magnetic fields and near power lines
  • Evidence on health
    • Childhood leukaemia
      • Pooled analyses of childhood leukaemia and magnetic fields
      • Number of children affected
      • Childhood leukaemia and night-time exposure
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • The “contact current” hypothesis
      • The causes of childhood leukaemia
    • Other health effects
      • Other childhood cancer
      • Breast cancer
      • Other adult cancers
      • Cardiovascular disorders
      • Neurodegenerative disorders
      • Epilepsy
      • Reproductive outcomes and disorders
      • Suicide and depression
      • Sleep disturbance
      • Asthma
      • Hypersensitivity
      • Effects of parental exposure to EMFs
    • Scientific review bodies
      • WHO
      • IARC
      • ICNIRP
      • SCENIHR
      • PHE (formerly HPA, formerly NRPB)
      • IET
      • NAS
      • NIEHS
      • California
      • Bioinitiative
    • Electric fields and ions
      • Electric fields and ions – a commentary on the suggestions
      • Electric fields and ions – NRPB comments
      • Skin cancer
      • Air pollution and childhood cancer
      • How many corona ions do power lines produce?
    • Comparing EMFs to other issues
      • EMFs compared to other issues: smoking
      • EMFs compared to other issues: passive smoking
      • EMFs compared to other issues: coffee
      • EMFs compared to other issues: shift work
      • EMFs compared to other issues: cholera
      • EMFs compared to other issues: BSE and variant CJD
      • Comparative risks
  • Research
    • Types of research
      • Research ethics
    • Epidemiology
      • Causation – what can epidemiology show and what can’t it?
      • Confounding
      • Clusters
    • Animal and laboratory experiments
      • Behaviour of large mammals in magnetic fields and near power lines
    • Mechanisms
      • Energy issues in mechanisms
      • Free radicals
      • Melatonin
      • Cryptochromes
      • Total field and AC field
    • Specific studies
      • UKCCS
      • CCRG
        • CCRG distance study
        • CCRG magnetic fields study
        • CCRG “corona ions” paper
        • CCRG follow-on paper
        • CCRG Underground cables paper
        • CCRG “wrap up” paper
        • CCRG Note on distance
        • Responses to the various CCRG papers
      • French Geocap study
      • California power lines study
      • Imperial College study
      • CEGB cohort
      • Transexpo
    • Ongoing research
      • UK electricity industry research
    • Non peer-reviewed science
    • Abstracts of papers
      • Childhood leukaemia abstracts
      • The CCRG (or “Draper”) study abstracts
      • The UKCCS abstracts
      • The CEGB cohort abstracts
      • Alzheimer’s disease abstracts
      • Breast cancer abstracts
      • Suicide and depression abstracts
      • Animal toxicology experiments abstracts
      • Numerical calculations of induced current – abstracts
      • Abstracts related to the Contact Current Hypothesis
      • Abstracts relating to research on fruit flies
      • Abstracts relating to animal behaviour: orientation in magnetic fields and sensing of power lines
  • Exposure limits
    • Limits in the UK
    • Limits in the USA
    • Limits in the EU
    • Limits in the rest of the world
    • Limits from specific organisations
      • ACGIH
      • NRPB 1993
      • ICNIRP 1998
      • EU 1999
      • ICES 2002
      • NRPB 2004
      • EU 2004
      • SBM 2008
      • ICNIRP 2010
      • EU 2013
      • The Control of Electromagnetic Fields at Work Regulations 2016
      • International Guidelines on Non-Ionising Radiation 2018
      • Comparison of exposure limits across frequencies
    • Indirect effects in exposure limits
    • Compliance with exposure limits
  • Policy
    • UK policy
      • Consent for power lines
      • Cross-Party Inquiry
      • Early Day Motions
      • Parliamentary Questions and Answers
      • UK Government and Parliament
    • European EMF policy
    • Power lines and property – UK
      • Corridors round power lines
    • Power lines and property – USA
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
      • Government response to SAGE First Interim Assessment
      • SAGE Second Interim Assessment
      • Government response to SAGE Second Interim Assessment
    • Public Opinion on EMFs
      • Opinion polls conducted by Ipsos MORI on power lines and EMFs
    • Communications on EMFs
    • Litigation on EMFs
  • Finding out more
    • Links
    • Literature
    • Contacts
    • Finding out about other issues
      • Finding out more: Wayleaves and easements
      • Finding out more: Safety clearance distances
      • “Danger of death” notices
      • Finding out more: Audible noise
      • Finding out more: Power lines and satellite navigation
      • Finding out more: Radio and TV interference
  • Static fields
    • Sources of static fields
      • Fields from underground DC cables
      • Effects of static fields on compasses
    • Effects of static fields
    • Static fields – the expert view
      • Types of medical devices
      • WHO – static fields
      • IARC – static fields
      • ICNIRP – static fields
      • PHE – static fields
    • Static field limits
You are here: Home / Current evidence on health / Childhood leukaemia / Number of children affected

Number of children affected

The pooled analysis by Ahlbom and others is usually interpreted as suggesting a relative risk of two for exposures to magnetic fields of greater than 0.4 µT. A relative risk of two is a doubling of risk.

This means long-term average fields in the child’s bedroom (24 hours or longer) of 0.4 µT, not short-term exposure above this level. More on the difference between fields in homes and personal exposure.

0.4% of children – 1 in 250 - in the UK live in homes with fields this high. This figure comes from the United Kingdom Childhood Cancer Study, the largest source of data that exists in the UK.

A relative risk of two applying to 0.4% of the population equates to roughly 0.4% of cases being attributable to magnetic fields (if, of course, the risk were a real one to start with). About 500 cases of leukaemia occur a year in children in the UK (more on the statistics of cancer). So the risk, if real, corresponds to about 2 extra cases a year in the UK. Of these 2, one would be due to power lines and one due to low voltage sources.

Some things to note about this calculation:

  • This is the number of extra cases. Survival for the commonest type of childhood leukaemia, Acute Lymphocytic Leukaemia, is approaching 80% in the UK.
  • This calculation takes the epidemiology at face value and assumes it shows a real risk. Of course, the risk may not exist at all (see some of the other things that could account for epidemiological results). Even if it does, the true relative risk would be unlikely to be exactly two. But this calculation is unlikely to be greatly wrong.
  • The epidemiological studies compared the children with fields greater than 0.4 µT to a reference group: children with fields less than 0.1 µT. We usually assume there would be no risk in this reference group. If there were a risk, the number of attributable cases would increase. Similarly, we assume there is no risk in the intermediate categories –0.1 – 0.2 µT and 0.2 - 0.4 µT.

The 2005 CCRG study found slightly raised rates of childhood leukaemia (but not any other childhood cancers) round 275 kV and 400 kV power lines in England and Wales. That paper says:

“If the association is causal, about 1% of childhood leukaemia [5 cases per year] in England and Wales would be attributable to these lines, though this estimate has considerable statistical uncertainty.”

This number – five cases per year – is bigger than the calculation from magnetic fields – two per year. This is because the effect the CCRG study found extends further from power lines than the magnetic-field effect would do. It may be evidence that the effect is caused by some other characteristic of the areas power lines pass through.

The 2007 WHO Environmental Health Criteria Monograph considers this issue at a global level and concludes:

"Although a causal relationship between magnetic field exposure and childhood leukaemia has not been established, the possible public health impact has been calculated assuming causality in order to provide a potentially useful input into policy. However, these calculations are highly dependent on the exposure distributions and other assumptions, and are therefore very imprecise. Assuming that the association is causal, the number of cases of childhood leukaemia worldwide that might be attributable to exposure can be estimated to range from 100 to 2400 cases per year. However, this represents 0.2 to 4.9% of the total annual incidence of leukaemia cases, estimated to be 49 000 worldwide in 2000. Thus, in a global context, the impact on public health, if any, would be limited and uncertain

Other possible causes

If magnetic fields don't cause more than a small fraction of childhood leukaemia, if indeed they cause any, what causes the rest?  We have a separate page with a discussion of this.

 

Statistics on cancer generally

This page talks about the numbers of children potentially affected by childhood leukaemia and EMFs.  See more information on the statistics of childhood cancer generally.

Latest news

  • How has the reported risk for childhood leukaemia changed over time? February 11, 2019
  • Media stories about microshocks in children’s playground September 10, 2018
  • New studies on leukaemia and distance from power lines June 1, 2018
  • UK media interest in the causes of childhood leukaemia May 22, 2018
older news

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To contact the electricity industry’s EMF Unit Public Information Line (UK only):
telephone 0845 7023270 or email EMFHelpLine@nationalgrid.com.

See Contact us for more contact details including our privacy policy.

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Navigation
  • What are EMFs
    • Terminology – an introduction
    • Electric fields
    • Magnetic fields
    • Units for measuring EMFs
    • Measuring and calculating EMFs
      • EMF instruments and other commercial services
    • Adding fields together
    • Radiofrequencies
    • Screening EMFs
  • Sources
    • Overhead power lines
      • Fields from specific power lines
        • 400 kV
        • 400 kV – specific cases
        • 275 kV
        • 132 kV
        • 66 kV
        • 33 kV
        • 11 kV
        • 400 V/230 V
        • Replacing a 132 kV line with a 400 kV line
      • Summaries of fields from all power lines
      • Factors affecting the field from a power line
        • Voltage
        • Current
        • Clearance
        • Height above ground
        • Conductor bundle
        • Phasing
        • Balance between circuits
        • Balance within circuit
        • Ground resistivity
        • Two parallel lines
      • Calculating and measuring fields from power lines
        • Geometries of power lines
        • Raw data
        • On-line calculator
      • Fields from power lines – more detail on the physics
        • Field lines from a power line
        • The direction of the field from a power line
        • Power law variations in the field from a power line
      • Statistics of power line fields
    • Underground power cables
      • Different types of underground cable
      • Fields from cables in tunnels
      • Gas Insulated Lines (GIL)
      • Underground cables with multiple conductors
      • Effect of height on fields from underground cables
      • Screening fields from underground cables
    • Low-voltage distribution
      • UK distribution wiring
      • USA distribution wiring
    • House wiring
    • Substations
      • National Grid substations
        • Static Var Compensators
      • Sealing-end compounds
      • Distribution substations
      • Final distribution substations
        • Indoor substations
    • Transport
      • EMFs from electric trains (UK)
      • EMFs from cars
    • Appliances
    • Electricity meters
      • Smart meters
      • Traditional meters
    • Occupational exposures
      • Live-line work
      • Static Var Compensators
      • Occupational exposures on pylons
    • Field levels and exposures
      • Personal exposure
      • Other factors that vary with magnetic fields
      • Fields greater than 0.2 or 0.4 µT
      • Fields in different countries
      • How fields vary with time
    • Reducing your exposure
  • Known effects
    • Induced currents and fields
      • Numerical calculations of induced currents
      • Details of numerical calculations of induced currents and fields in the body
    • Effects of EMFs on equipment
    • EMFs and medical devices
      • Types of medical devices
      • Real-life experience of interference with Implanted Heart Devices
      • Laboratory Tests of Implanted Medical Devices
      • Consequences if interference does occur with an implanted heart device
      • Manufacturers of Implanted Heart Devices
      • Standards relating to pacemakers and other AIMDs
      • Interference with hearing aids and cochlear implants
    • Microshocks
      • Control of microshocks in the UK
      • Microshocks from bicycles
    • EMFs, agriculture and the environment
      • Bees and microshocks
      • Behaviour of large mammals in magnetic fields and near power lines
  • Evidence on health
    • Childhood leukaemia
      • Pooled analyses of childhood leukaemia and magnetic fields
      • Number of children affected
      • Childhood leukaemia and night-time exposure
      • Survival from childhood leukaemia
      • Childhood leukaemia and Downs
      • The “contact current” hypothesis
      • The causes of childhood leukaemia
    • Other health effects
      • Other childhood cancer
      • Breast cancer
      • Other adult cancers
      • Cardiovascular disorders
      • Neurodegenerative disorders
      • Epilepsy
      • Reproductive outcomes and disorders
      • Suicide and depression
      • Sleep disturbance
      • Asthma
      • Hypersensitivity
      • Effects of parental exposure to EMFs
    • Scientific review bodies
      • WHO
      • IARC
      • ICNIRP
      • SCENIHR
      • PHE (formerly HPA, formerly NRPB)
      • IET
      • NAS
      • NIEHS
      • California
      • Bioinitiative
    • Electric fields and ions
      • Electric fields and ions – a commentary on the suggestions
      • Electric fields and ions – NRPB comments
      • Skin cancer
      • Air pollution and childhood cancer
      • How many corona ions do power lines produce?
    • Comparing EMFs to other issues
      • EMFs compared to other issues: smoking
      • EMFs compared to other issues: passive smoking
      • EMFs compared to other issues: coffee
      • EMFs compared to other issues: shift work
      • EMFs compared to other issues: cholera
      • EMFs compared to other issues: BSE and variant CJD
      • Comparative risks
  • Research
    • Types of research
      • Research ethics
    • Epidemiology
      • Causation – what can epidemiology show and what can’t it?
      • Confounding
      • Clusters
    • Animal and laboratory experiments
      • Behaviour of large mammals in magnetic fields and near power lines
    • Mechanisms
      • Energy issues in mechanisms
      • Free radicals
      • Melatonin
      • Cryptochromes
      • Total field and AC field
    • Specific studies
      • UKCCS
      • CCRG
        • CCRG distance study
        • CCRG magnetic fields study
        • CCRG “corona ions” paper
        • CCRG follow-on paper
        • CCRG Underground cables paper
        • CCRG “wrap up” paper
        • CCRG Note on distance
        • Responses to the various CCRG papers
      • French Geocap study
      • California power lines study
      • Imperial College study
      • CEGB cohort
      • Transexpo
    • Ongoing research
      • UK electricity industry research
    • Non peer-reviewed science
    • Abstracts of papers
      • Childhood leukaemia abstracts
      • The CCRG (or “Draper”) study abstracts
      • The UKCCS abstracts
      • The CEGB cohort abstracts
      • Alzheimer’s disease abstracts
      • Breast cancer abstracts
      • Suicide and depression abstracts
      • Animal toxicology experiments abstracts
      • Numerical calculations of induced current – abstracts
      • Abstracts related to the Contact Current Hypothesis
      • Abstracts relating to research on fruit flies
      • Abstracts relating to animal behaviour: orientation in magnetic fields and sensing of power lines
  • Exposure limits
    • Limits in the UK
    • Limits in the USA
    • Limits in the EU
    • Limits in the rest of the world
    • Limits from specific organisations
      • ACGIH
      • NRPB 1993
      • ICNIRP 1998
      • EU 1999
      • ICES 2002
      • NRPB 2004
      • EU 2004
      • SBM 2008
      • ICNIRP 2010
      • EU 2013
      • The Control of Electromagnetic Fields at Work Regulations 2016
      • International Guidelines on Non-Ionising Radiation 2018
      • Comparison of exposure limits across frequencies
    • Indirect effects in exposure limits
    • Compliance with exposure limits
  • Policy
    • UK policy
      • Consent for power lines
      • Cross-Party Inquiry
      • Early Day Motions
      • Parliamentary Questions and Answers
      • UK Government and Parliament
    • European EMF policy
    • Power lines and property – UK
      • Corridors round power lines
    • Power lines and property – USA
    • Precaution
    • SAGE
      • SAGE First Interim Assessment
      • Government response to SAGE First Interim Assessment
      • SAGE Second Interim Assessment
      • Government response to SAGE Second Interim Assessment
    • Public Opinion on EMFs
      • Opinion polls conducted by Ipsos MORI on power lines and EMFs
    • Communications on EMFs
    • Litigation on EMFs
  • Finding out more
    • Links
    • Literature
    • Contacts
    • Finding out about other issues
      • Finding out more: Wayleaves and easements
      • Finding out more: Safety clearance distances
      • “Danger of death” notices
      • Finding out more: Audible noise
      • Finding out more: Power lines and satellite navigation
      • Finding out more: Radio and TV interference
  • Static fields
    • Sources of static fields
      • Fields from underground DC cables
      • Effects of static fields on compasses
    • Effects of static fields
    • Static fields – the expert view
      • Types of medical devices
      • WHO – static fields
      • IARC – static fields
      • ICNIRP – static fields
      • PHE – static fields
    • Static field limits