Testing the effectiveness of small radiation shields for mobile phones

Nine small radiation shields made to adhere to the case of mobile phones were tested at 914 and 1880 MHz. Five popular products were tested because advertisements typically claim they are up to 99% effective in blocking radio frequency (RF) radiation emitted from mobile phones. Also, four other conceptually unusual products were tested because advertisements typically claim they emit oscillations that counteract the RF radiation from mobile phones. Each shield was tested on the same mobile phone, and measurements were made to compare the absorption of RF energy in the head with and without each shield attached to the phone. The phone was positioned against a head model, and an automated measurement process was used to determine specific absorption rate (SAR) in the same way it is used at Motorola to test the compliance of mobile phones with respect to human exposure limits. The location of the peak SAR was not observed to change with any of the shields attached to the phone, and the 1 g, peak spatial average SAR did not change by any statistically significant amount. These results indicate the small shields are ineffective in reducing the exposure of the head to RF energy emitted by a mobile phone.     

Skin temperature increase caused by a mobile phone: a methodological infrared camera study

Mobile phone users often complain about burning sensations or a heating of the ear region. The increase in temperature may be due to thermal insulation by the phone, heating of the mobile phone resulting from its electrical power dissipation, and radio frequency (RF) exposure. The main objective of this study was to use infrared (IR) camera techniques to find how much each of these factors contributes to the increase in skin temperature resulting from the use of one GSM 900 phone. One subject, a healthy male, took part in the study. He was holding the phone in a normal position when the phone was switched off, when it was switched on but with the antenna replaced by a 50 Omega load to eliminate the RF exposure, and when it was transmitting RF fields. The output power could be fixed, and the minimal and the maximal power levels of the phone were used. The study was designed as a double blind experiment. The changes in temperature after 15 and 30 min of mobile phone use were calculated on the exposed side of the head relative to the unexposed side. The insulation and the electrical power dissipation led to statistically significant rises in the skin temperature, while the RF exposure did not.     

Combining near‐ and far‐field exposure for an organ‐specific and whole‐body RF‐EMF proxy for epidemiological research: A reference case

A framework for the combination of near‐field (NF) and far‐field (FF) radio frequency electromagnetic exposure sources to the average organ and whole‐body specific absorption rates (SARs) is presented. As a reference case, values based on numerically derived SARs for whole‐body and individual organs and tissues are combined with realistic exposure data, which have been collected using personal exposure meters during the Swiss Qualifex study. The framework presented can be applied to any study region where exposure data is collected by appropriate measurement equipment. Based on results derived from the data for the region of Basel, Switzerland, the relative importance of NF and FF sources to the personal exposure is examined for three different study groups. The results show that a 24‐h whole‐body averaged exposure of a typical mobile phone user is dominated by the use of his or her own mobile phone when a Global System for Mobile Communications (GSM) 900 or GSM 1800 phone is used. If only Universal Mobile Telecommunications System (UMTS) phones are used, the user would experience a lower exposure level on average caused by the lower average output power of UMTS phones. Data presented clearly indicate the necessity of collecting band‐selective exposure data in epidemiological studies related to electromagnetic fields. Bioelectromagnetics 34:366–374, 2013. © 2012 Wiley Periodicals, Inc.     

Effects of GSM cellular phones on human hearing: the European project "GUARD"

The European multicenter project named GUARD involved nine centers and aimed to assess potential changes in auditory function as a consequence of exposure to low-intensity electromagnetic fields (EMFs) produced by GSM cellular phones. Participants were healthy young adults without any evidence of hearing or ear disorders. Auditory function was assessed immediately before and after exposure to EMFs, and only the exposed ear was tested. The procedure was conducted twice in a double blinded design, once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). Tests for assessment of auditory function were hearing threshold level (HTL), transient otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR). The exposure consisted of speech at a typical conversational level delivered via an earphone to one ear, plus genuine or sham EMF exposure. The EMF exposure used the output of a software-controlled consumer cellular phone at full power for 10 min. A system of phone positioning that allowed participants to freely move their heads without affecting exposure was used. Analysis of the data showed there were no effects of exposure to GSM mobile phone signals on the main measures of the status of the auditory system.     

Measurements of skin surface temperature during mobile phone use

We measured maximum temperature rises on the side of the face after 6 min of continuous mobile phone operation using two models of AMPS analog phones operating in the 835 MHz band and three early model GSM digital phones operating in the 900 MHz band. For the GSM phones the highest recorded temperature rise difference was 2.3 degrees C and for the AMPS phones it was 4.5 degrees C, both at locations on the cheek. The higher differential temperature rise between AMPS and GSM may reflect the higher maximum average operating power of AMPS (600 mW) versus GSM900 (250 mW). Additionally, we compared temperature changes at a consistent location on the cheek for an AMPS phone that was inoperative (-0.7 degrees C), transmitting at full power (+2.6 degrees C) and in stand-by mode (+2.0 degrees C). Our results suggest that direct RF heating of the skin only contributes a small part of the temperature rise and that most is due to heat conduction from the handset.     

Does acute exposure to mobile phones affect human attention?

Recent studies have indicated that acute exposure to low level radiofrequency (RF) electromagnetic fields generated by mobile phones affects human cognition. However, the relatively small samples used, in addition to methodological problems, make the outcomes of these studies difficult to interpret. In our study we tested a large sample of volunteers (168) using a series of cognitive tasks apparently sensitive to RF exposure (a simple reaction task, a vigilance task, and a subtraction task). Participants performed those tasks twice, in two different sessions. In one session they were exposed to RFs, with half of subjects exposed to GSM signals and the other half exposed to CW signals, while in the other session they were exposed to sham signals. No significant effects of RF exposure on performance for either GSM or CW were found, independent of whether the phone was positioned on the left or on the right side.     

Mobile phones, radiofrequency fields, and health effects in children--epidemiological studies

In 2004, when WHO organized a workshop on children's sensitivity to electromagnetic fields, very few studies on radiofrequency fields were available. With the recent increase in mobile phone use among children and adolescents, WHO has identified studies on health effects in this age-group as a high priority research area. There are no empirical data supporting the notion that children and adolescents are more susceptible to RF exposure, but the number of studies is still relatively small. There are a few cross-sectional studies on well-being, cognitive effects and behavioral problems, and some cohort studies, mainly of maternal use of mobile phones during pregnancy. Cancer outcomes have been studied in relation to environmental RF exposure, e.g. from transmitters, and only one study on mobile phone use in children and adolescents and brain tumor risk has been published. Several methodological limitations need to be taken into consideration when interpreting the findings of the epidemiological studies. The cross-sectional design does not allow determination of the temporal sequence of exposure and outcome, and for several outcomes there is a large potential for reversed causality, i.e. that the outcome causes an increased RF exposure rather than the opposite. Biases such as recall errors in self-reported mobile phone use, lack of confounding control, e.g. of other aspects of mobile phone use than RF fields, trained behaviors, and pubertal development, makes causal interpretations impossible. Future studies need to include prospectively collected exposure information, incident outcomes, and proper confounding control. Monitoring of brain tumor incidence trends is strongly recommended.     

Hypersensitivity symptoms associated with exposure to cellular telephones: no causal link

The hypothesis that there exist hypersensitive persons who perceive subjective symptoms from radiofrequency (RF) fields emitted by hand held mobile phones (cellular phones) was tested using double blind provocation experiments. We also tested whether sensitive subjects are able to determine whether the phone is on or off by sensing RF fields. The study group consisted of 20 volunteers (13 women and 7 men) who reported themselves as being sensitive to cellular phones. The RF exposure sources were one analogue NMT phone (900 MHz) and two digital GSM phones (900 and 1800 MHz). The duration of a test session was 30 min, and three or four sessions were performed in random order for each subject during 1 day. The subjects were asked to report symptoms or sensations as soon as they perceived any abnormal feelings. In addition, the subjects' blood pressure, heart rate, and breathing frequency were monitored every 5 min. The results of the study indicated that various symptoms were reported, and most of them appeared in the head region. However, the number of reported symptoms was higher during sham exposure than during real exposure conditions. In addition, none of the test persons could distinguish real RF exposure from sham exposure. Hence, we conclude that adverse subjective symptoms or sensations, though unquestionably perceived by the test subjects, were not produced by cellular phones.     

The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: an experimental provocation study

Findings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self-reported symptoms and detection of fields after a prolonged exposure time and with a well defined study group including subjects reporting symptoms attributed to mobile phone use. The design was a double blind, cross-over provocation study testing a 3-h long GSM handset exposure versus sham. The study group was 71 subjects age 18-45, including 38 subjects reporting headache or vertigo in relation to mobile phone use (symptom group) and 33 non-symptomatic subjects. Symptoms were scored on a 7-point Likert scale before, after 1(1/2) and 2(3/4) h of exposure. Subjects reported their belief of actual exposure status. The results showed that headache was more commonly reported after RF exposure than sham, mainly due to an increase in the non-symptom group. Neither group could detect RF exposure better than by chance. A belief that the RF exposure had been active was associated with skin symptoms. The higher prevalence of headache in the non-symptom group towards the end of RF exposure justifies further investigation of possible physiological correlates. The current study indicates a need to better characterize study participants in mobile phone exposure studies and differences between symptom and non-symptom groups.     

Mobile phone use and location of glioma: A case–case analysis

We assessed a new approach for evaluating the glioma risk among users of mobile phones to focus on the part of the brain most heavily exposed to radiofrequency electromagnetic fields from mobile phones. The tumor midpoint was defined from radiological imaging. A case–case analysis with 99 gliomas was performed using logistic regression. The exposed cases were those with the tumor mid‐point within 4.6 cm from the line between the mouth and the external meatus of the ear, representing the most likely location of the mobile phone (the source of exposure). Alternative analyses based on various indicators of mobile phone use as the outcome were also carried out. The majority of cases were regular mobile phone users. A slightly higher proportion of gliomas among mobile phone users than non‐users occurred within 4.6 cm from the presumed location of the mobile phone (28% vs. 14%). Modestly elevated odds ratios were observed for several indicators of mobile phone use, but without an exposure gradient. The highest odds ratios were found for contralateral and short‐term use. Our results, though limited by the small sample size, demonstrate that detailed information on tumor location allows evaluation of the risk related to the most heavily exposed part of the brain, representing direct evaluation of the possible local carcinogenic effects of the radiofrequency fields. However, field strength varies between users and over time also within a given anatomic site, due to the output power of the phone. Collaborative analysis of a larger sample is planned. Bioelectromagnetics 30:176–182, 2009. © 2009 Wiley‐Liss, Inc.     

Estimation of head tissue-specific exposure from mobile phones based on measurements in the homogeneous SAM head

The maximum spatial peak exposure of each commercial mobile phone determined in compliance with the relevant safety and product standards is publicly available. However, this information is not sufficient for epidemiological studies aiming to correlate the use of mobile phones with specific cancers or to behavioral alterations, as the dominant location of the exposure may be anywhere in the head between the chin to above the ear, depending on the phone design. The objective of this study was to develop a methodology to determine tissue-specific exposure by expanding the post-processing of the measured surface or volume scans using standardized compliance testing equipment, that is, specific absorption rate (SAR) scanners. The transformation matrix was developed using the results from generic dipoles to evaluate the relation between the SAR in many brain regions of the Virtual Family anatomical phantoms and in virtual brain regions mapped onto the homogeneous SAM head. A set of transformation factors was derived to correlate the SAR induced in the SAM head to the SAR in the anatomical heads. The evaluation included the uncertainty associated with each factor, arising from the anatomical differences between the phantoms (typically less than 6 dB (4×)). The applicability of these factors was validated by performing simulations of four head models exposed to four realistic mobile phone models. The new methodology enables the reliable determination of the maximum and averaged exposure of specific tissues and functional brain regions to mobile phones when combined with mobile phone power control data, and therefore greatly strengthens epidemiological evaluations and improves information for the consumer.     

Systematic review of wireless phone use and brain cancer and other head tumors

We conducted a systematic review of scientific studies to evaluate whether the use of wireless phones is linked to an increased incidence of the brain cancer glioma or other tumors of the head (meningioma, acoustic neuroma, and parotid gland), originating in the areas of the head that most absorb radiofrequency (RF) energy from wireless phones. Epidemiology and in vivo studies were evaluated according to an agreed protocol; quality criteria were used to evaluate the studies for narrative synthesis but not for meta-analyses or pooling of results. The epidemiology study results were heterogeneous, with sparse data on long-term use (≥ 10 years). Meta-analyses of the epidemiology studies showed no statistically significant increase in risk (defined as P < 0.05) for adult brain cancer or other head tumors from wireless phone use. Analyses of the in vivo oncogenicity, tumor promotion, and genotoxicity studies also showed no statistically significant relationship between exposure to RF fields and genotoxic damage to brain cells, or the incidence of brain cancers or other tumors of the head. Assessment of the review results using the Hill criteria did not support a causal relationship between wireless phone use and the incidence of adult cancers in the areas of the head that most absorb RF energy from the use of wireless phones. There are insufficient data to make any determinations about longer-term use (≥ 10 years).     

Time trends (1998-2007) in brain cancer incidence rates in relation to mobile phone use in England

Mobile phone use in the United Kingdom and other countries has risen steeply since the early 1990's when the first digital mobile phones were introduced. There is an ongoing controversy about whether radio frequency (RF) exposure from mobile phones increases the risk of brain cancer. However, given the widespread use and nearly two decades elapsing since mobile phones were introduced, an association should have produced a noticeable increase in the incidence of brain cancer by now. Trends in rates of newly diagnosed brain cancer cases in England between 1998 and 2007 were examined. There were no time trends in overall incidence of brain cancers for either gender, or any specific age group. Systematic increases in rates for cancers of the temporal lobe in men (0.04 new cases/year) and women (0.02/year) were observed, along with decreases in the rates of cancers of the parietal lobe (-0.03/year), cerebrum (-0.02/year) and cerebellum (-0.01/year) in men only. The increased use of mobile phones between 1985 and 2003 has not led to a noticeable change in the incidence of brain cancer in England between 1998 and 2007. The observed increase in the rate of cancers in the temporal lobe, if caused by mobile phone use, would constitute <1 additional case per 100,000 people in that period. These data do not indicate a pressing need to implement a precautionary principle by means of population-wide interventions to reduce RF exposure from mobile phones.     

Influence of electromagnetic fields emitted by GSM-900 cellular telephones on the circadian patterns of gonadal, adrenal and pituitary hormones in men

The potential health risks of radiofrequency electromagnetic fields (RF EMFs) emitted by mobile phones are currently of considerable public interest. The present study investigated the effect of exposure to 900 MHz GSM radiofrequency radiation on steroid (cortisol and testosterone) and pituitary (thyroid-stimulating hormone, growth hormone, prolactin and adrenocorticotropin) hormone levels in 20 healthy male volunteers. Each subject was exposed to RF EMFs through the use of a cellular phone for 2 h/day, 5 days/ week, for 4 weeks. Blood samples were collected hourly during the night and every 3 h during the day. Four sampling sessions were performed at 15-day intervals: before the beginning of the exposure period, at the middle and the end of the exposure period, and 15 days later. Parameters evaluated included the maximum serum concentration, the time of this maximum, and the area under the curve for hormone circadian patterns. Each individual's pre-exposure hormone concentration was used as his control. All hormone concentrations remained within normal physiological ranges. The circadian profiles of prolactin, thyroid-stimulating hormone, adrenocorticotropin and testosterone were not disrupted by RF EMFs emitted by mobile phones. For growth hormone and cortisol, there were significant decreases of about 28% and 12%, respectively, in the maximum levels when comparing the 2-week (for growth hormone and cortisol) and 4-week (for growth hormone) exposure periods to the pre-exposure period, but no difference persisted in the postexposure period. Our data show that the 900 MHz EMF exposure, at least under our experimental conditions, does not appear to affect endocrine functions in men.     

Analysis of proteome response to the mobile phone radiation in two types of human primary endothelial cells

Background  

Use of mobile phones has widely increased over the past decade. However, in spite of the extensive research, the question of potential health effects of the mobile phone radiation remains unanswered. We have earlier proposed, and applied, proteomics as a tool to study biological effects of the mobile phone radiation, using as a model human endothelial cell line EA.hy926. Exposure of EA.hy926 cells to 900 MHz GSM radiation has caused statistically significant changes in expression of numerous proteins. However, exposure of EA.hy926 cells to 1800 MHz GSM signal had only very small effect on cell proteome, as compared with 900 MHz GSM exposure. In the present study, using as model human primary endothelial cells, we have examined whether exposure to 1800 MHz GSM mobile phone radiation can affect cell proteome.     

Mobile phone radiation and the developing brain: behavioral and morphological effects in juvenile rats

The increasing use of mobile phones by children and teenagers has raised concerns about their safety. Addressing such concerns is difficult, because no data are available on possible effects from long-term exposure to radiofrequency (RF) fields during the development of the nervous system. Possible morphological and functional changes were evaluated in the central nervous system of young male Wistar rats exposed to 900 MHz mobile phone signal for 2 h/day on 5 days/week. After 5 weeks of exposure at whole-body average specific energy absorption rates of 0.3 or 3.0 W/kg or sham exposure, six rats per group were examined histologically, and the remaining 18 rats per group were subjected to behavioral tests. No degenerative changes, dying neurons, or effects on the leakage of the blood-brain barrier were detected. No group differences were observed in the open-field test, plus maze test or acoustic startle response tests. In the water maze test, however, significantly improved learning (P = 0.012) and memory (P = 0.01) were detected in rats exposed to RF fields. The results do not indicate a serious threat to the developing brain from mobile phone radiation at intensities relevant to human exposure. However, the interesting finding of improved learning and memory warrants further studies.     

Electromagnetic fields and epidemiology: An overview inspired by the fourth course at the International School of Bioelectromagnetics

The fourth course at the International School of Bioelectromagnetics addressed various aspects of the epidemiology of exposure to electromagnetic fields (EMF). In this overview, inspired by the lectures and the discussions among participants, we summarize current knowledge on exposure to EMF and disease risk, with emphasis on studies of use of mobile phones and brain tumours and exposure to power lines and childhood leukaemia. Sources of bias and error hamper straightforward conclusions in some areas and, in order to move forward, improvements in study design and exposure assessment are necessary. The scientific evidence available to date on possible long‐term effects from exposure to ELF and RF fields is not strong enough to revise current protection limits based on the known acute effects of such exposures. Precautionary measures may be considered to reduce ELF exposure of children or exposure to RF during mobile phone use, keeping in mind that it is unclear whether they involve any preventive benefit. Possible health effects from mobile phone use in adults and in children should be investigated further by prospective epidemiological studies with improved exposure assessment and brain tumour incidence rates should be monitored. Further studies on the relation between childhood leukaemia and ELF magnetic fields would be worthwhile if they focus on heavily exposed groups and attempt to minimize possible selection bias. In conclusion, epidemiological studies conducted with appropriate diligence can play a key role in finding the answers. Bioelectromagnetics 30:511–524, 2009. © 2009 Wiley‐Liss, Inc.     

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on well-being and resting EEG

Modern mobile phones emit electromagnetic fields (EMFs) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. To date most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies were concerned with Universal Mobile Telecommunications System (UMTS)-EMF. Consequently, we tested the effects of both types of EMF, 1950 MHz UMTS (SAR 0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on well-being and vigilance-controlled resting electroencephalogram (eyes closed) in 15 healthy, right-handed subjects. A double-blind, randomised, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.     

Effects of RF exposure of teenagers and adults by CDMA cellular phones

Many cellular phone provocation studies have been conducted since the question of increased health risk from extended usage of cellular phones became a social issue. Internationally, most studies have been conducted regarding the effects of GSM cellular phones on blood pressure and heart rate of adult volunteers. On the other hand, very few provocation studies have been conducted regarding the physiological effects of CDMA phones on teenagers. In this study, two volunteer groups consisting of 21 teenagers and 21 adults were exposed to 300 mW of radio frequency (RF) electromagnetic field emitted by a CDMA cellular phone for half an hour. Physiological parameters such as systolic and diastolic blood pressures, heart rate, respiration rate, and skin resistance were simultaneously measured. All the parameters for both groups were unaffected during the exposure except for decreased skin resistance of the teenager group (P < .0001). For the regrouped 23 male and 19 female subjects, all the parameters for both groups were unaffected during the exposure except for decreased skin resistance of the male subjects (P = .0026). Those resistances at 10 min after the terminated exposure returned to the resistances at rest regardless of the different groups of age and sex.     

Effects of mobile phone electromagnetic fields on an auditory order threshold task

The effect of acute exposure to radio frequency electromagnetic fields (RF EMF) generated by mobile phones on an auditory threshold task was investigated. 168 participants performed the task while exposed to RF EMF in one testing session (either global system for mobile communication (GSM) or unmodulated signals) while in a separate session participants were exposed to sham signals. Lateralization effects were tested by exposing participants either on the left side or on the right side of the head. No significant effect of exposure to RF EMF was detected, suggesting that acute exposure to RF EMFs does not affect performance in the order threshold task.