The Group recognised that they would have to examine the issue of possible non-thermal effects very carefully. They also accepted that the pulsed signals associated with modern digital mobile phones were different to exposures from the older analogue phones, which were continuous, and that it would be necessary to consider whether this was important. There was some discussion about the nature of the evidence that is required in order to set guidelines on restricting exposure. The interpretation of epidemiological evidence was complex, and there could be uncertainties even with large and apparently well-designed studies. It was important to ensure that good epidemiological studies are carried out to provide data for the future.
Epidemiological evidence needs to be viewed in the context of results from laboratory studies.
However, individual experimental studies can be flawed, so it is generally required that results should be replicated in at least two independent laboratories. Although the Expert Group felt that their conclusions should be based on data published in the peer-reviewed literature, they were interested in considering other findings and could use them as a basis for recommending further research. Given the current uncertainties with respect to the scientific evidence, some participants expressed the view that it would be sensible to adopt a precautionary approach. The Expert Group had already identified this as an issue that they would need to consider. It would be necessary for the Group to examine the options.