The communications protocols used by mobile phones often result in low-frequency pulsing of the carrier signal. Whether these modulations have biological significance has been subject to debate.
Some researchers have argued that so-called "non-thermal effects" could be reinterpreted as a normal cellular response to an increase in temperature. The German biophysicist Roland Glaser, for example,has argued that there are several thermoreceptor molecules in cells, and that they activate a cascade of second and third messenger systems, gene expression mechanisms and production ofheat shock proteinsin order to defend the cell against metaboliccell stresscaused by heat. The increases in temperature that cause these changes are too small to be detected by studies such as REFLEX, which base their whole argument on the apparent stability of thermal equilibrium in their cell cultures.
Other researchers believe the stress proteins are unrelated to thermal effects, since they occur for both extremely low frequencies (ELF) and radio frequencies (RF), which have very different energy levels.
Blood-brain barrier effects
Swedish researchers fromLund University(Salford, Brun, Perrson, Eberhardt, and Malmgren) have studied the effects of microwave radiation on the rat brain. They found a leakage ofalbumininto the brain via a permeatedblood-brain barrier.This confirms earlier work on the blood-brain barrier by Allan Frey, Oscar and Hawkins, and Albert and Kerns.Other groups have not confirmed these findings in cellor animal studies.
Cancer
In 2006 a large Danish study about the connection between mobile phone use and cancer incidence was published. It followed over 420,000 Danish citizens for 20 years and showed no increased risk of cancer. The German Federal Office for Radiation Protection (BfS) considers this report inconclusive.
The following studies of long time exposure have been published:
§The 13 nation INTERPHONE project - the largest study of its kind ever undertaken - has now been published and did not find a solid link with mobile phones and brain tumours.
TheInternational Journal of Epidemiologypublisheda combined data analysis from a multi national population-based case-control study of glioma and meningioma, the most common types of brain tumour.
The authors reported the following conclusion:
Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long-term heavy use of mobile phones require further investigation.
In thepress releaseaccompanying the release of the paper, Dr Christopher Wild, Director of the International Agency for Research on Cancer (IARC) said:
An increased risk of brain cancer is not established from the data from Interphone. However, observations at the highest level of cumulative call time and the changing patterns of mobile phone use since the period studied by Interphone, particularly in young people, mean that further investigation of mobile phone use and brain cancer risk is merited.
