Mobile phones: carcinogenic and other potential risks

The article by Lee at al. [1] contains no direct statements on the harm from radio-frequency electromagnetic fields (RF-EMF). However, certain phrases may create an impression that the harm is probable, e.g., “Extensive use of mobile phones, even among children, has incited public concern regarding the possible negative effects on human health resulting from exposure to the RF-EMF radiation emitted by such devices” or in the conclusion section: “The issue of whether children are more sensitive to RF-EMF emitted from mobile phones has been a hot topic among many researchers over the past two decades [1].” These statements can be understood so as if “sensitivity” or “negative effects” would have been known facts. It should be commented that there is no consistent evidence that RF-EMF enhances cancer risk. The only recognized biological effect is heating, which for cell phones are negligible [2,3]. According to the International Agency for Research on Cancer (IARC), there is limited evidence for the carcinogenicity of RF-EMF, although there was a minority opinion in the IARC that the evidence in humans is inadequate [4,5]. Indeed, several epidemiological studies reported associations between RF-EMF and glioma, acoustic neuroma and other tumors [6-17]. Other studies did not confirm such associations [18-21] or even identified a reduced risk of brain tumors among mobile phone users (which the authors identified as probably due to selection bias and thus did not report a protective effect), although odds ratios for glioma tended to be greater in subjects who reported usual phone use on the same side of the head as their tumor than on the opposite side [18,20]. However, the ipsilateral effect found in low exposure groups suggested that cases might have over-reported the use on the side of the tumor [18]. According to the Scientific Committee on Emerging Newly Identified Health Risks, the epidemiological studies on mobile phone RF-EMF exposure do not show an overall increased risk of brain tumors [22]. A considerable number of well-performed in vivo studies have been negative [22]. Numerous in vitro studies have been negative as well, whereas the more research quality criteria were satisfied, the less cellular responses were observed [23]. Furthermore, a publication bias has been noticed, i.e. preferred publication of positive results [22]. The existing data were found to be not sufficiently strong to suggest that RF-EMF is directly genotoxic, while some of the reported “adverse effects” may be attributed to hyperthermia [4]. Biases are known to occur in the epidemiologic research (dose-dependent self-selection, recall bias, etc.,), for ionizing radiation discussed in Jargin’s study [24]. To confirm a cause-effect relationship, verification by reliable methods and understanding of the mode of action are needed [25]. No experimental findings can provide an explanation for supposed carcinogenicity of RF-EMF, thus no established biological or biophysical mechanisms of action exist so far [3,23,26]. Large-scale animal experiments could provide more information, for example, this study being conducted by the National Toxicology Program in the US.