Comment to BMJ article, ‘Are some people sensitive to mobile phone signals?’
From Frans van Velden
Comment to ‘Are some people sensitive to mobile phone signals?’
The article ‘Are some people sensitive to mobile phone signals?’
by Rubin c.s. was published recently in British Medical Journal (15 April 2006 in BMJ 2006;332:886-891, doi:10.1136/bmj.38765.519850.55) (to be found here:
Frans van Velden MSc
Rubin et al. define electromagnetic sensitivity as a condition in which symptoms are reported AFTER perceived exposure. This is not the definition of electromagnetic (hyper)sensitivity (EHS). EHS is a condition in which symptoms are reported as related to and attributed to exposure to electromagnetic fields (WHO factsheet 296, to be found here:
It has been suggested that symptoms might arise from environmental factors unrelated to electromagnetic fields. There are some indications that symptoms may be due to worries about health effects of electromagnetic fields, rather than the exposure itself. Some studies suggest that reactivity in the central nervous system and imbalance in the autonomic nervous system in EHS afflicted tend to be outside the normal range (WHO factsheet 296). The suggestion of Rubin, that perceived exposure is the cause of symptoms, is contradictionary to ‘Whatever its cause …’ (WHO factsheet 296).
Usually EHS is assumed on the basis of single-blind experiences, exposure is confirmed afterwards by environmental data or measurements. According to WHO factsheet 296 no scientific basis currently (i.e. December 2005) exists for a connection between EHS and electromagnetic fields. This is under discussion. High frequency electromagnetic fields have proven effects on biological systems. They intensify the neuronal activity, influence the cerebral bloodflow and brain activity, damage DNA and indications that they cause headaches are concrete (Report for T-Mobile, Jülich Institute, 9 May 2005, to be found here:
Rubin et al. write ‘Participants were exposed to .. a sham exposure with no signal present’ (Abstract, Intervention). This is contradictionary to their clarification ‘For the sham exposure, a continuous wave signal was generated .. only a minimal leakage of this signal occurred (SAR < 0,002 W/kg)' (Methods, Exposures). It means Rubin et al. answered the research question beforehand. They assumed people are not sensitive to a signal when the SAR is less than 0,002 W/kg. David Bücher from Darmstadt already made clear that 2 mW/kg is even above the SAR during the exposure phase of the study by Zwamborn et al. in 2003 (rapid response to be found here:
Figure 2 of Rubin et al. (to be found here:
Rubin et al. confirm that the symptoms were not trivial. They are puzzled by the results. Did some inadequacy exist in the methods? The sensitivity of the visual analogue scales and the statistical techniques did not have any short-comings. However, they overlook one simple, uncomplicated explanation: the SAR is not an indicator of how worse the scenario. A ‘sham’ signal with 0,002 W/kg triggered about the same headache severity as a GSM-signal with 1,4 W/kg. This corresponds with people reporting being sensitive to mobile phones at distances of one metre or more. Dr. Gro Harlem Brundtland, former head of the WHO, reported headaches by stand-by mobile phones closer than four metres, abating until half an hour after the phones were turned off (Aud Dalsegg, Dagbladet Norge, 9 March 2002).
Instead Rubin et al. choose a vague and complicated explanation, the nocebo (‘I will harm’) effect. Again, they answer the research question beforehand, by the assumption that all exposures do not cause symptoms. However, the nocebo effect can not fully explain the results. The headaches of the self-declared non-sensitive people can not be attributed to a nocebo effect, since these people do not believe a mobile phone can do harm. The growth and decline of the headache severities of the non-sensitive people are not random, they show the same pattern as of the sensitive people, the only difference is less severity.
A nocebo effect would imply a difference between the two groups. Rubin et al. did not find any difference from the questionnaires or demographic data. There is no indication of different behaviour, lifestyle, personality. No indication of a different attitude to modern electromagnetic equipment. Many self-declared sensitive people have a positive attitude to mobile communication and were early adaptors. According to Rubin et al. it is interesting that symptom severity increased during exposition. A nocebo effect indeed would produce a different picture. Nocebo effects are usually vague. Figure 2 is not vague at all.
In medicine, a nocebo effect means people re-label existing ailments as side effects of their medication (Arthur Barsky). This means people who have headaches, whatever the cause, start to attribute them to mobile phone use. So, the self-declared sensitive people should report headaches before and in between of mobile phone use too. The headaches should stay away when using a mobile phone and being told there is no field (placebo effect). Nocebo is a learning process. The attribution of a headache to a mobile phone call is rather unlikely, since it is a positive experience to be able to communicate with other people freely.
Instead of accepting the simple and straightforward explanation (electromagnetic fields cause headaches) Rubin et al. walk into the swamp of nocebo and placebo effects. Why? Rubin: “Right. There was no difference in symptom severity between our sham condition and the active conditions which were approximately 700 times stronger. I think that’s quite good evidence that it wasn’t the RF (radio frequency) that was causing the symptoms.” Simplified, Rubin says a train driving 4.5 km/hour can not hurt anybody, because it has 700 times less energy than a train driving 110 km/hour. The effect of the first train is nocebo, so the effect of the second train is also nocebo. If people who do not think a train can hurt are hit, they also suffer from nocebo effects.
The interaction of electromagnetic fields and biological systems is not like that. There is an abundance of sources, producing together the environmental factor electromagnetic fields, with local density and structure (frequencies, modulations) variable in time. There are many people with different sensitivities to different effects, therefore suffering from different consequences. Rubin et al. have been found coherent results by provocation. They found evidence that the concrete indications that electromagnetic fields cause headaches are true. People who ignore this, are suffering from a nolebo (‘I don’t want to’) effect.
Correspondence to fransp@dds.nl