EPIDEMIOLOGY Interphone, the world’s widest survey
When it comes to risk prevention, epidemiology – the statistical study of the relationship between a potential threat and its real effects on human health – is the essential first step before any sound diagnosis can be made. But before such an analysis is possible, sufficient time must have elapsed since the appearance of the threat, and the study population must be sufficiently large and representative. In the case of mobile telephone use, the ambitious European Commission supported Interphone study was launched as soon as these two conditions could be met. Its initial global conclusions are awaited with great interest as they will provide the first knowledge base for an objective debate on the principle of precaution when using mobile phones.
It all began in 1998. The use of mobile phones was still very recent at that time but it was already becoming clear that this was a major technological invention destined to have a major social impact. Hundreds of millions of people were to become mobile phone users. Two major international organisations, the ICNRP,(1) responsible for setting electromagnetic protection levels, and the World Health Organisation, felt directly concerned by this technological innovation. They assembled a team of experts of global renown to look at its potential impact. What was known about the possible consequences and risks of the EM radio frequencies generated by these new devices, used in such close proximity to the brain and with very different properties to traditional telephones? The answer was: very little.
All the available epidemiological data on exposure to radio frequencies related to limited population groups who suffered exposure in a work environment (in radar or medical occupations, for example) and under very different conditions. The evaluation methodologies for these specific risks were also far from standardised and little suited to an analysis of this new invention that had taken the consumer society by storm.
Inventing a method "Already at this time we were looking at the feasibility of a study that we named Interphone and that would be designed specifically to look at this new problem,” explains project coordinator Elisabeth Cardis, director of the International Agency for Research on Cancer (IARC), an offshoot of the WHO with its headquarters in Lyons (FR). “Teams of specialists from 13 countries – the study would only be of value if it was conducted on a very wide scale so as to avoid any regional bias – agreed to concentrate their research on the development of very specific kinds of tumours of the cranial system: certain brain tumours (gliomas and meningiomas), tumours of the parotids or salivary glands, and tumours of the acoustic nerve (neurinomas) or of the lymphatic tissue (lymphomas).
It now remained to carefully select the control populations to be studied for mobile phone use. They were selected exclusively in areas where the technology had been adopted early on, at least between five and ten years previously. While this is the case for quite large areas of Northern Europe, elsewhere penetration at this time was primarily in large urban areas. Interphone also limited its study population to working people aged between 30 and 59, for whom there is the greatest likelihood of a long-standing and continuous use of mobile phones.
After defining all these criteria, the statistical potential on which the teams began to work produced a significant sample: approximately 6 000 people showing gliomas or meningiomas (at a serious or benign stage), 1 000 cases of acoustic nerve neurinoma, and 600 parotid gland tumours.
Interviewing and cross-checking On this basis, the researchers carried out personalised and in-depth interviews of the control groups to assess for how long and how frequently they used mobile phones. Important details were recorded carefully – including which ear the mobile phone is usually held against. This is a valuable element, in particular when considering the condition of the acoustic or salivary system.
These recall data were then compared with the invoicing data available from the service operators, the network technical characteristics and the phones used. Finally, a personal investigation was carried out to detect other genetic or environmental factors that may have interacted.
“Many national or regional studies, either completed or nearing completion, are currently being gathered by the IARC,” explains Elisabeth Cardis. “Various teams have communicated incomplete results. These all report an absence of effects, with the exception of one, published by a Swedish team and concerning acoustic nerve neurinomas (see box). But the Interphone results will only have any real value when they have been analysed and validated in their entirety. This global evaluation will not be completed before 2006.”
(1) International Commission for Non-Ionising Radiation Protection
In October 2004, the Institute of Environmental Medicine at Stockholm’s famous Karolinska Institute issued a press release that caused a certain degree of concern. It revealed that the examination of 150 cases of neurinoma – a benign tumour of the acoustic nerve that grows very slowly and ...
The Interphone epidemiological study really took shape in 2000 when, in addition to national funding, it received substantial financial support from the European Union: maximum contribution of €3 850 000 for four years under the Fifth Framework Programme. Danish, Finnish, French, ...
In October 2004, the Institute of Environmental Medicine at Stockholm’s famous Karolinska Institute issued a press release that caused a certain degree of concern. It revealed that the examination of 150 cases of neurinoma – a benign tumour of the acoustic nerve that grows very slowly and is quite rare (estimated at one case for every 1 000 000 people) – disclosed a doubling of the risk among intensive users of mobile phones “for at least ten years’ duration”. A worrying detail was that this risk increased fourfold for the side of the skull generally used for the device.
While not objecting to the publicity the information had attracted, the researchers themselves expressed the view that these findings should be treated with the greatest caution, primarily because the study sample of people presenting such tumours was very small. The Interphone study would provide more exhaustive results concerning 1 000 examinations of neurinoma sufferers. The specification of “at least ten years’ duration” (no increased risk being identified before this period) perhaps also indicated a problem of technology. The first telephones used were analogue and “nothing permits us to affirm that these long-term results concern the use of digital telephones of the GSM generation…,” point out the researchers.
The Interphone epidemiological study really took shape in 2000 when, in addition to national funding, it received substantial financial support from the European Union: maximum contribution of €3 850 000 for four years under the Fifth Framework Programme. Danish, Finnish, French, German, Italian, Swedish, Norwegian and British teams joined the project, as well as an Israeli institute of medicine. These were later joined by four other international partners (Australia, Canada, Japan, New Zealand), bringing to 13 the number of countries covered by the study. Additional financing was also provided by the UICC (International Union Against Cancer). The latter has a particularly important role in channelling funds from two private bodies representing the mobile phone industry, the Mobile Manufacturers' Forum and the GSM Association. "The acceptance of this material support from the industry is governed by a clause strictly guaranteeing the absolute scientific independence of the studies carried out under the aegis of Interphone,” stresses Elisabeth Cardis.