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15 November 2018

BERENIS (Swiss Expert Group on EM Fields and Non-Ionizing Radiation): Evaluation of NTP and Ramazzini Studies

BERENIS (Swiss expert group on EM fields and non-ionizing radiation) Newsletter, 13 November 2018,  on evaluation of NTP and Ramazzini studies: (click on "November newsletter") in this link:


The NTP and Ramazzini studies are most comprehensive animal studies with regard to cancer and exposure to mobile phone and base station signals that have been conducted to date. The scientific quality and standard of laboratory techniques are high, especially in the NTP study. Compared to earlier studies with laboratory animals that evaluated carcinogenicity or co-carcinogenicity of RF EMF, these studies are novel in that the animals were exposed roaming freely in their cages instead of being placed in narrow tubes for exposure. This reduced the stress caused by confinement and allowed for longer daily exposures.

The results of these two animal studies are of great scientific relevance and importance for health policy because according to the International Agency for Research on Cancer (IARC), positive results from animal studies with lifetime exposure are very important with regard to the classification of cancer risk of an agent, together with data from epidemiological and mechanistic studies. Based on the observed evidence regarding a correlation between mobile phone use and gliomas as well as acoustic neuroma, the latter data led to the IARC classification of mobile phone radiation as ‘possibly carcinogenic’ (group 2B) in 2011. The IARC classifies the risk that an agent or environmental toxin causes cancer in humans into five groups, namely ‘probably not carcinogenic’ (group 4), ‘not classifiable’ (3), ‘possibly carcinogenic’ (2B), ‘probably carcinogenic’ (2A) or ‘carcinogenic’ (1).

Despite the methodological differences, both new animal studies showed relatively consistent results in schwannomas and gliomas, as well as a dose-dependent trend to an increase in the carcinogenicity of these tumors. The NTP study used high whole-body doses (SAR – specific absorption rates) as compared to the regulatory limits for whole-body exposure recommended by ICNIRP. For the general public, this limit is 0.08 W/kg, with Switzerland additionally having introduced lower precautionary limits. The question arises of how transferable the NTP study results are to real-life exposure of the public, considering that mobile phone use exposes only parts of the body to EMF levels comparable to the ones applied to the whole animal by the NTP study. First, it is common practice in toxicology to study higher doses to evaluate possible hazards of an agent. Second, the NTP study found an increase in carcinogenicity for GSM and CDMA exposure conditions. Since the findings are similar for both types of exposure, they indicate that the modulation of the signals does not seem to be relevant. Third, mobile phone use can cause local SAR values up to 2 W/kg, averaged over a cube of 21 mm side length in the closest proximity of the phone (e.g. at the ear, cheeks, hand, pocket locations, etc.). Thus, the results of the NTP study are mostly relevant for the exposure situation when using a mobile phone close to the body. In contrast, the Ramazzini study observed carcinogenicity at levels as high as the environmental exposure limits, with no statistically significant effect at lower doses. However, a dose-dependent trend was found for malignant heart schwannomas, which is consistent with the findings of the NTP study. This may indicate that the non-significant increase in case numbers at lower exposure levels represents a true effect that has not reached statistical significance due to the given sample size.

In summary, BERENIS supports a precautionary approach for regulating RF EMF based on the findings and their evaluation. A full risk assessment analysis taking into account all available studies (animal studies and epidemiological studies) is necessary to assess whether the current standards should be changed.

For a link to the German text, click on "Sonderausgabe November 2018"

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