Mobile Phone : RF exposure assessment for INTERPHONE study
Results published in june 2008
Abstract
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Work under the current proposal involves two complementary aspects: the development of the RF exposure gradient algorithm and its application to the INTERPHONE study subjects and the analysis of the relation between risk of the tumour of interest and RF exposure level.
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Publications
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E. Cardis, I. Deltour, S. Mann et al.
Distribution of RF energy emitted by mobile phones in anatomical structures of the brain.
Physics in Medicine and Biology 53 (2008)
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Partners
Centre international de recherche sur le cancer (CIRC), LYON
Site : www.iarc.fr
Official contact
Dr Elisabeth Cardis
CIRC
Duration
9 mois
Summary
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The INTERPHONE study, with 13 participating countries co-ordinated by IARC, aims to determine whether mobile telephone use increases the risk of cancer and, specifically, whether the radio frequency (RF) radiation emitted by mobile telephones is carcinogenic. This objective is being achieved by carrying out studies of tumours which, if RF is carcinogenic, would be those most likely to be related to mobile telephone use as they occur in the cells which receive most of the exposure: gliomas, meningiomas and tumours of the acoustic nerve and of the parotid gland.
The studies are population-based in each country. In order to maximise the power of finding a risk if it exists, the studies are mainly focused on tumours in relatively young people (30-59 years of age), who had the highest prevalence of mobile phone use 5 to 10 years ago, and on regions within the participating countries with longest and highest use of mobile phones.
Data collection and validation has now been completed.
The INTERPHONE Study includes data on 2613 gliomas, 2343 meningiomas, 1105 acoustic neurinomas, 400 parotid gland tumours and their respective controls. This is by far the largest epidemiological study of these tumours to date.
Information on history of mobile telephone use was collected by trained interviewers during a face-to-face interview, with the use of a computer assisted questionnaire (CAPI). An attempt was made to elicit some information from non-respondents.
The volumic distribution of the Specific Absorption Rate (SAR) in the head depends on many different parameters including: the frequency band, the phone model, the position of the phone in relation to the head. An essential aspect of the exposure assessment study was to determine whether radiation patterns from different phones differ significantly and, if so, to classify the phones into a limited number of categories with distinct spatial patterns of exposure.
Following detailed analyses at IARC of data on spatial distribution of energy in the head based on results of experiments conducted in over 100 different phone models from different countries and time periods and using different technologies and frequency bands, distinct classes of mobile phones have now been defined. For each phone in these classes, the estimated average SAR in each cube of the grid shown above is currently being estimated by the laboratories that made the original measurement using an extrapolation method that has been developed and tested over the last year. The data should be received at IARC in September and generic distributions in each class of phones will then be developed on the basis of the distribution of energy in the different cubes from all the phones in the class.
Other aspects of the exposure which have been assessed include: the effects of adaptive power control (APC) and discontinous transmission (DTX); the effects of different exposures circumstances; the effects of the network and trends in SAR values over time. Throughout the course of the INTERPHONE Study, information has been collected on the effects of APC and DTX (mainly in GSM networks) and on historical characteristics of networks (including frequencies and technologies used, and enablement of power control and DTX). A comprehensive historical SAR database had also been compiled allowing analyses of temporal trends. A study of the effects of exposure circumstances has been conducted through the use of software-modified phones for periods of one month by groups of volunteers in different INTERPHONE countries/regions, by measurement campaigns in countries with non-GSM networks, and by studies of output power from base stations in urban and rural areas.
All of these aspects will be included, together with information on historical phone use, in an RF exposure index .
Description of work
Work under the current proposal involves two complementary aspects: the development of the RF exposure gradient algorithm and its application to the INTERPHONE study subjects and the analysis of the relation between risk of the tumour of interest and RF exposure level.
The following outcomes are foreseen:
• estimates of RF exposure (cumulative absorbed energy overall and in time windows) in each cell of the three-dimensional cartography of the head for INTERPHONE subjects.
• a manuscript on the INTERPHONE RF exposure gradient; and
• a manuscript on the relation between RF exposure and the risk of brain, acoustic nerve and parotid gland tumours.
The latter results will form the basis for the statistical analyses of the relation between RF exposure and the risk of brain tumours, which will be conducted in early 2006.