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can people really sense exposure to emfs?

Back in 2007, I was the MC at a Cafe Scientifique focused on high-voltage power lines. Then, as now, there was concern that the electromagnetic fields (EMFs) around these high-voltage lines posed a health hazard, so I did quite a bit of reading around the subject (as always, we had experts along to lead the discussion, but I always like to be prepared!). And so it was that I was introduced to the topic of 'electromagnetic sensitivity', something I was reminded of this week when friends sent me the link to a website claiming that the smart meters currently being installed by many electricity suppliers are a health hazard due to the EMFs** they emit.

Now, the question of electrosensitivity is one that Ben Goldacre wrote about in some detail on his Bad Science website, back in May 2006 (with a number of follow-up articles as related stories hit the UK press),and it's also covered on the excellent science-based website EMF & Health. Ben kicked off his 2006 piece thusly: 

"Electromagnetic fields stemming from gadgets such as kettles, computers and microwaves, contribute towards a cloud of unseen emissions - even when they are switched off." It's a sinister idea, and "Electromagnetic Hypersensitivity" is sweeping the nation, or at least the Independent and the Daily Mail last week. Symptoms include fatigue, tiredness, headaches, concentration difficulties, dizziness, nausea, heart palpitations, and digestive disturbances: and since these are real symptoms, causing genuine distress, the problem deserves to be considered seriously, and carefully.

The immediate question - and it's worth asking of the smart-meters site too - is, what is the scientific evidence to support claims that EMF 'smog' affects people's health? And also, if there is an apparent correlation between exposure and ill-health, does that equate to a causal relationship?

At this point, it's also worth saying that - like Ben Goldacre & indeed pretty much everyone who's written on this subject from the evidence-based science perspective - I don't think those reporting electromagnetic sensitivity are hypochondriacs. Their symptoms exist & many sound rather unpleasant. The question is whether those symptoms are due to EMF exposure.

When Ben wrote his original piece he found that there were 31 published studies that examined the claims for EMF sensitivity; that is,

whether people who report being hypersensitive to electromagnetic fields can detect their presence, or if their symptoms are worsened by them.

A meta-analysis of those 31 papers is available here, & it's important to note that in many cases the researchers measured actual symptoms as well as whether or not the participants could detect EMFs. The majority of these studies (N=24) found no evidence to support that hypothesis. Of the remaining 7 research projects, it turned out that the results were "statistical artefacts" (3 studies - the stats issues are explained very well in the Bad Science article), or could not be replicated, not even by the original authors (2 studies); the last 2 studies produced mutually inconsistent results.

However, scientists didn't stop there; the question of whether "electromagnetic sensitivity" is real continues to be the focus of research. With pretty much the same findings. For example, in 2008 the Health Council of the Netherlands found (page 73 of the pdf at this link) that 

Both in the living environment and in the laboratory, studies have been performed into a possible link between exposure to electromagnetic fields and the occurrence of symptoms. Several of these studies were not properly designed and cannot be used for the analysis

and concluded

From the good quality scientific data emerges the picture that there is no causal relationship between exposure to radio-frequency electromagnetic fields and the occurrence of symptoms. However, there is a relationship between symptoms and the assumption of being exposed and therefore most likely with the risk perception. Nevertheless, the symptoms do exist and require a solution.

A 2010  project updated the 2005 meta-analysis, adding a further 15 studies, and again found no link, saying that

Despite the conviction of IEI-EMF sufferers that their symptoms are triggered by exposure to electromagnetic fields, repeated experiments have been unable to replicate this phenomenon under controlled conditions

and a study published earlier this year also found no correlation between participants' symptoms and their actual exposure to EMFs. The authors of this paper go further, concluding that 

Media reports about the adverse effects of supposedly hazardous substances can increase the likelihood of experiencing symptoms following sham exposure and developing an apparent sensitivity to it. Greater engagement between journalists and scientists is required to counter these negative effects.

Back to where we began: on the plus side, the smart-meters website does admit that the various health problems it lists (headaches, insomnia, fatigue, muscle aches, memory problems, and alterations in moods including irritability, depression, and anxiety attacks - all vague, in the sense that it's often hard to pin down a cause) 

are not necessarily due to EMR exposure, so anyone with these symptoms should consult their doctor to determine the cause. If the problem is due to EMR exposure, the symptoms should subside when the person is not exposed.

True enough, although the author does definitely incline to the idea of a causal relationship - in the face of an awful lot of evidence to the contrary.

**Also, now that I think of it , the author also seems to be conflating EMFs and EMR, where the latter stands for electromagnetic radiation. We're exposed to forms of EMR - eg radio waves - all the time (unless living indoors 24/7, in a fully tinfoil-lined house with no electricity supply), so the exposure's not going to stop any time soon. Which I suppose leads on to a form of confirmation bias. 

Nor does it help that the very first link on their faqs page is to the (in)famous whale.to website...

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