Saturday, September 29, 2018

Exposure to electromagnetic fields (EMF) – Biological effects vs health effects

We often see media articles that claim new research has found health effects from human exposure of some chemical or physical agent. In the case of electromagnetic fields (EMF), we have seen such studies claiming effects of exposure to EMF. But what is rarely discussed is whether the claimed ‘effect’ is a biological effect or indeed a health effect. What’s the difference you ask? 

In the recent MWF publication “20 years of research[1]”, we tried to explain this difference: 

Biological effects are a response to stimulus or to a change in the environment around you and are not necessarily bad for your health. Health effects are changes in health resulting from exposure to an agent or source. Eating a freezing cold ice cream can give you a ‘brain-freeze’ (ice-cream headache), a sensation which goes away a short time after you stop eating it. Going for a run or sitting in a sauna will cause your body temperature to rise. These biological effects are not considered health effects because the result is temporary and not detrimental to your health.

Further explanations on the difference between “biological effects” and “health effects” in particular in regards to exposure to EMF, can be found in the factsheet of the World Health Organization[2](WHO) on electromagnetic fields. There the WHO states: 

Biological effects are measurable responses to a stimulus or to a change in the environment. These changes are not necessarily harmful to your health. For example, listening to music, reading a book, eating an apple or playing tennis will produce a range of biological effects. Nevertheless, none of these activities is expected to cause health effects. The body has sophisticated mechanisms to adjust to the many and varied influences we encounter in our environment. Ongoing change forms a normal part of our lives. But, of course, the body does not possess adequate compensation mechanisms for all biological effects. Changes that are irreversible and stress the system for long periods of time may constitute a health hazard.

An adverse health effect causes detectable impairment of the health of the exposed individual or of his or her offspring; a biological effect, on the other hand, may or may not result in an adverse health effect.

It is not disputed that electromagnetic fields above certain levels can trigger biological effects. Experiments with healthy volunteers indicate that short-term exposure at the levels present in the environment or in the home do not cause any apparent detrimental effects. Exposures to higher levels that might be harmful are restricted by national and international guidelines. The current debate is centred on whether long-term low level exposure can evoke biological responses and influence people's well being.

The definition by the Institute of Electrical and Electronic Engineers (IEEE)[3], although a little more technical is also useful: 

"Established adverse health effect: A biological effect characterized by a harmful change in health that is supported by consistent findings of that effect in studies published in the peer-reviewed scientific literature, with evidence of the effect being demonstrated by independent laboratories, and where there is consensus
in the scientific community that the effect occurs for the specified exposure condition." versus the biological effect as “alterations of the structure, metabolism, or functions of a whole organism, its organs, tissues, and cells. Biological effects can occur without harming health and can be beneficial. Biological effects also can include adaptive responses."

From these different explanations, we can clearly see that there is an important difference between a biological effect and a health effect, even though many articles do not differentiate between the two – whether it is in relation to EMF or in other contexts. 

So when you are reading the next article, it might be interesting to see whether the authors make the proper distinction between the two, and if they don’t, it may say something important about the quality of the reporting. 


MWF’s “20 years of research” booklet:

WHO’s factsheet “What are electromagnetic fields?”: (accessed 5 September 2018) 

Institute of Electrical and Electronic Engineers Inc (IEEE) IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields,3 kHz to 300 GHz. IEEE; Piscataway, NJ, USA: 2006.

[1]MWF’s “20 years of research” booklet:
[2]WHO’s factsheet “What are electromagnetic fields?”: (accessed 5 September 2018)
[3]Institute of Electrical and Electronic Engineers Inc (IEEE) IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields,3 kHz to 300 GHz. IEEE; Piscataway, NJ, USA: 2006.

Wednesday, September 19, 2018

EMF Research and the Weight of Scientific Evidence

We have all seen media articles that claim that a new study has “proven” a chemical or physical agent causes some health effect, usually cancer. While such results might look scary or at least surprising to the reader, scientists usually react differently and point to the “weight of scientific evidence”. What does this term mean and how does it apply to scientific studies related to electromagnetic fields (EMF) research?

As summarized in the MWF’s booklet on “20 years of research”,

The ‘weight of scientific evidence’ approach means that no single study can answer any scientific question, and must not be viewed in isolation but against the backdrop of previous research. Factors such as the quality of the data, consistency of results, nature and severity of effects and relevance of the information are all important considerations for experts to determine appropriate weighting to be given to the evidence. This approach is important to consider in research on radiofrequency (RF) electromagnetic field (EMF) health effects when individual studies provide different or conflicting results. Individual studies need to be seen in the light of the total research effort into mobile phone health and safety. Scientific investigation is subject to potential errors, personal opinions and uncertainties. This applies as much to research on RF EMF health effects as it does to all other areas of science.

The concept of “weight of scientific evidence” is not exclusive to research on EMF but is a key principle in scientific work. The European Food Safety Authority’s (EFSA) scientific committee has published for example a “Guidance on the use of the weight of evidence approach in scientific assessments”. In this Guidance it states:

Weight of evidence assessment is a process in which evidence is integrated to determine the relative support for possible answers to a scientific question. The term ‘weight of evidence’ on its own is the extent to which evidence supports possible answers to a scientific question. This is what is assessed by weight of evidence assessment, and can be expressed qualitatively or quantitatively. 

The European Commission’s Scientific Committee on Health, Environmental and Emerging Risks (SCHEER)  published in June 2018 a revision of their “Memorandum on weight of evidence and uncertainties”, which defines the weight of evidence as

A process of weighted integration of lines of evidence to determine the relative support for hypotheses or answers to a question. 

All of this does not mean that single studies are ignored or not important. They are integrated into the body of knowledge and put into context with all the other studies and research that have been carried out on the subject in question. As the World Health Organization  has stated, “(i)n the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years.” And as a result “scientific knowledge in this area is now more extensive than for most chemicals.”


MWF’s “20 years of research” booklet (2018):

EFSA’s “Guidance on the use of the weight of evidence approach in scientific assessments” (2017):

SCHEER’s “Memorandum on weight of evidence and uncertainties” (2018):

World Health Organization: What are electromagnetic fields?