Radiation literature survey

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This paper described the results of a systematic review and meta-analysis of in vitro studies that investigated the association between extremely low frequency (ELF) magnetic fields (MF) and calcium homeostasis (which is an indicator of efficient signalling between cells in the body). The systematic review, which included a total of 42 studies, showed evidence of an association. The meta-analysis revealed that there was a statistically significant effect of ELF MF exposure on both the frequency of calcium oscillations and intracellular calcium levels. Although the results supported an association between ELF MF exposure and calcium homeostasis, the authors noted that high heterogeneity in the different studies weakened the findings.

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This is a human provocation study that investigated whether electromagnetic fields (EMF) exposure is associated with adverse health symptoms. A total of 72 people (36 claiming to have electromagnetic hypersensitivity, EHS, and 36 controls) were given sham exposure to an MF source (the participants were blinded to the exposure). Anxiety, EMF-related worries, and other subjective symptoms were assessed via questionnaires. People who claimed to have EHS reported more symptoms and had higher levels of anxiety than the controls. The authors suggested that somatosensory amplification is the biggest contributor to EHS.

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This is an in vitro study that investigated whether radiofrequency (RF) exposure has any effects on cancer cells. Three types of human cancer cells (leukaemia, breast cancer, and hepatic cancer cells) were exposed to RF via the RF identification (RFID) microchip technology. The exposure was at a frequency of 134.2 kilohertz (kHz) and no exposure level was indicated. Four experiment settings were compared which involved all possible combinations of inactive/active activator (where the signal is generated) and with/without microchip. The authors found that the RF exposure emanating from the active microchip slowed down the growth of cancer cells.

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This Australian cohort study investigated whether there is an association between wireless phone use and cognitive function in children. The cohort included a total of 619 children aged 8-11 years from schools in Melbourne and Wollongong. Information on mobile and cordless phone use was obtained via questionnaires and the children were tested for cognitive function. Overall, there was no support of an association between wireless phones use and cognitive function in primary school-aged children.

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This paper reported the results that were obtained at the start of the cohort study (baseline), which will be compared to the results obtained at a later time (after a period of follow-up).

As commented on January 2016’s report, studies investigating cognitive effects of mobile phone use on children have yielded inconsistent results so far.

Obtaining information via questionnaires can produce information bias. In this study by Redmayne et al, it was interesting to note that many children reported themselves as using a mobile phone whereas the parents reported that they were not using it.

Another interesting finding was that there was a significant difference in the reaction time (which is a measured parameter of cognitive function) on one of the tasks between girls and boys (gender effects), which may warrant further investigation.

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This is a human provocation study which investigated whether the RF heating effects cause harm to human eyes. The study involved 16 head and neck cancer patients that were treated by hyperthermia, which used intense RF radiation at a frequency of 434 megahertz (for 60 minutes per treatment). The effects of stray radiation received by the eyes were examined. The peak local specific absorption rate (SAR) and temperature increase in the eye was at least 62 watts per kilogram (W/kg) (6.2 times the limit of the Australian Standard) and 1.8°C (the Australian Standard is providing protection against temperature increase of 1°C), respectively. There were no serious ocular effects even though the subjects were overexposed. The authors concluded that the current international guidelines on RF (to which the Australian Standard is aligned) provide adequate protection against adverse health effects.

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p>This is a cross-sectional study that investigated the effects of low level radiofrequency (RF) radiation on cognitive and behavioural functions in children. A subset of 123 boys aged 9-11 years that originally enrolled in a cohort study was surveyed and evaluated for their cognitive and behavioural functions. Environmental RF exposure was assessed via spot measurements at the residences of the participants. The median power density level was 285.94 microwatts per meter-squared (μW/m2), which is hundreds of times below the public exposure limit in the Australian RF Standard. The authors found no overall effects on cognitive and behavioural functions.

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Two cohort studies that investigated behavioural problems in children where the mothers had maternal RF exposure from wireless phones have reported little or no evidence of behavioural effects in the offspring (reported as feature articles in February 2010 and February 2013 reports).

Two human provocation studies done in children on cognitive functions did not find any effects (Haarala et al, 2004 and Preece et al, 2005) as reported in the Health Effects from Radiofrequency Electromagnetic Fields report by the Advisory Group on Non-Ionising Radiation.

A cross-sectional study on cognitive effects from RF radiation in adolescents (reported as a feature article in August 2010) found that increased exposure of RF radiation causes changes in cognitive functions. However the authors noted that the self-assessment of wireless phone use to be the major limitation of the study.

This study by Calvente et al which also follows a cross-sectional design is prone to many methodological limitations which were noted by the authors. Although the exposure assessment was done via measurements, they were spot measurements outside the residences of the study participants, which may not be an adequate surrogate of individual exposure. Furthermore, cross-sectional studies assess the relationship between the exposure and outcome at one time point only hence it is very difficult to draw conclusions from the results.

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This animal study investigated whether low level RF radiation from Wi-Fi causes any adverse health effects. Sixteen rats were divided into two groups (sham and exposed) and experimented for one year. The RF exposure was at a frequency of 2.4 gigahertz and whole-body average SAR of 0.141 milliwatts/kg (which is 0.18% of the limit in the Australian Standard). The DNA damage on the rat’s brain, liver, kidney, skin and testicular tissues were quantified. The authors found a statistically significant increase in DNA damage only in the testicular tissues of the exposed group. The authors therefore conclude that the testes are more sensitive to RF radiation than the other organs studied.

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This case-control study investigated the association between RF radiation from mobile phones and a type of brain cancer. A total of 285 glioma patients (cases) and 285 controls were recruited in the study. Information on mobile phone use was obtained via questionnaires. The authors reported no statistically significant increased risk with the cumulative hours of mobile phone use at the same side of the head as the tumour (odds ratio, OR = 1.77; 95% confidence interval, 95% CI = 0.32 – 1.84), when compared to the use at the other side of the head. The authors concluded that there was no association between gliomas and mobile phone use.

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This population-based case-control study tried to examine the association between occupational exposures to extremely low frequency (ELF) magnetic fields (MF) and breast cancer in men. A total of 115 cases and 570 controls participated in the study. The MF exposure was estimated via expert assessment, using the information on participants’ job histories, where the average MF exposure for individual jobs was classified into three categories (less than 0.3, 0.3 to less than 0.6, and 0.6 microtesla, μT or more). There was a non-significant increased risk of breast cancer in men who were exposed to 0.6 μT or more (OR = 1.80, 95% CI = 0.82-3.95) when compared to the group exposed to less than 0.3 μT. The study found inconsistent association between occupational MF exposure and breast cancer in men.

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This is a computer simulation study of the RF radiation emanating from up to 15 wireless devices in the closed environment of a train carriage. In the study the specific absorption rate (SAR) for an individual is assessed from all wireless devices in the train carriage. The authors found that 15 other users connected to a GSM900 base station external to the train can induce SARs up to 24% of that induced by a user’s own device.

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