- Do cell phones or cell phone base stations cause headaches?
In 1998, Frey reported anecdotal evidence that cell phones cause headaches.
In 2000, Oftedal et al found that users of cell phones commonly report having headaches, but since the study contains no data on non-users it is not known whether the rate of headaches reported by these cell phone users is unusual. An extension of the study by Sandström et al reported that headaches and other symptoms were higher in users of analog (NMT 900) phones than users of digital (GSM) phones.
In 2000, Chia et al reported that headaches were significantly more common among users of hand-held cell phones than among non-users (65% vs 54%). Headache prevalence increase significantly with duration of use, and the use of hand-free equipment eliminated the increase.
No one has claimed that there is scientific evidence that base stations cause headaches, and there are no biophysical or physiological bases for expecting such an effect.
- Does radio-frequency radiation from cell phones or cell phone base stations cause physiological or behavioral changes?
- Braune et al reported that human volunteers using a GSM cell phone for 35 minutes showed a 5-10 mm Hg rise in blood pressure. The study is small and was not blinded, and a rise in blood pressure of this magnitude has no known health consequences.
- Eulitz et al reported that cell phones can alter the electrical activity of the brain. However, the effect may be an artifact caused by RF interference with the EEG leads.
- Freude et al exposed human volunteers to RF from a 916 Mhz 350 mW GSM digital phone. Small changes in EEG were seen that "did not indicate any influence on human performance, well-being and health"
- In 1996 Mann and Röschke reported that exposure to a mobile phone signal at 0.05 mW/cm-sq could cause slight changes in sleep patterns; but subsequent studies by the same group found no significant effect when the power density was lowered to 0.02 mW/cm-sq, and no effect at all when the power density was increased to 5 mW/cm-sq - In 1999, Borbély, Huber and colleagues reported that exposure to a mobile phone signal at 1 W/kg could cause slight changes in sleep patterns and sleeping EEG.
- De Seze et al reported that exposure of human volunteers to cell phone RF had no effect on night-time secretion of melatonin. Effects on melatonin have been suggested as a mechanism by which power line fields might affect human health - Wang and Lai reported that rats exposed to 2450 MHz pulsed radio-frequency radiation showed "defects in long-term memory". The RF-exposed animals were slower than normal animals to learn a maze. Animals received whole-body RF exposure for 1 hr/day. The average SAR was 1.2 W/kg with peaks of 3-4 W/kg. The signal is quite different from that associated with a mobile phone base station and the peak SAR may have been high enough to cause thermal stress. The exposure intensity (SAR) was 15 times higher than the FCC standard for whole-body exposure of the general public. In 2000 Sienkiewicz et al performed a similar experiment in mice (but using a signal and a power-density simulating a European digital cell phone base station signal) and found no effects on maze performance.
- In 1999, Preece et al reported that exposure of human volunteers to cell phone RF radiation might decrease reaction times. The press coverage was extensive; but the actual study has no obvious implications for human health, since the effect was seen for just one of many tests of cognitive function and it appears to be far too small to have any real functional significance.
- In 2000, Koivisto et al reported studies of human volunteers who were exposed to 902 MHz RF from a 250 mW digital (GSM) phone and given a battery of reaction time tests. For some tests, exposure reduced (improved) the time required, other tests showed less significant time improvements. Some tests showed no significant effects. For the test in which Preece et al found an effect for the analog signal, Koivisto et al found no effect for a digital signal. The tests showing effects are stated to be tests of cognitive function. In further studies in 2001, Koivisto et al found that a 30-60 minute exposure to RF radiation from GSM phones had no detectable subjective effects on human volunteers.
- In 2000, Krause et al reported a study of human volunteers who were exposed to 902 MHz RF from a 250 mW digital (GSM) phone and given memory and reaction time tests. Effects on error rate and reaction time were not significant. Some effects on EEG were observed under some test conditions. According to the authors: "The present results do not allow any conclusions concerning the possible effects of cellular phone use on cognition".
- In 2000 Tsurita et al reported that RF radiation had no effect on the blood-brain barrier in rats. These rats were exposed to a 1339 MHz digital (TDMA) signal for one hour per day for 2-4 weeks. The average whole body SAR was 0.25 W/kg and the brain SAR was 2 W/kg, and no changes in body temperature were observed. No effects were observed on body weight, brain morphology or blood-brain barrier permeability. The Tsurita et al paper includes a detailed discussion of previous studies of RF effects on the blood-brain barrier.
- In 2000, Bornhausen and Scheingraber reported that exposure of pregnant rats to RF radiation has no effect on the behavior of their off-spring. Free-roaming pregnant rats were continuously exposed to 900 MHz GSM RF at 0.1 mW/cm-sq (SARs ranged from 17.7-75 mW/kg). No cognitive deficits were found in their offspring.
For a review of the behavioral effects of RF radiation see D'Andrea
- Can RF radiation produce biological effects?
There have been scattered reports of effects that do not appear to be due to heating, the so called non-thermal effects .None of these effects have been independently replicated, and none have any obvious connections to human health risks.
The lack of biological effects from exposures to radio-frequency radiation that do not produce biologically significant temperature changes is not surprising, as there are no known biophysical mechanisms that would suggest that such effects were likely .
In a 2001 review, Pickard and Moros conclude that:
tissue is so small as to make unlikely any significant nonthermal biological effect." "The prospects of UHF (300-3000 MHz) irradiation producing a nonthermal bioeffect are considered theoretically and found to be small... This supports previous arguments for the improbability of biological effects at UHF frequencies unless a mechanism can be found for accumulating energy over time and space and focusing it. Three possible mechanisms are then considered and shown to be unlikely... Finally, it is concluded that the rate of energy deposition from a typical fields and within a typical..
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