Review of 29 Studies: Does Cell Phone EMF Damage DNA?
One of the most sensational and often repeated claims by alarmists is that cell phone EMF can damage DNA. If this were true, it would be a legitimate cause for concern, since DNA damage can lead to cancer. Therefore this is an area that has been the focus of much research.
The following is a collection of abstracts of in vitro and in vivo studies looking at whether cell phones can damage DNA. As this collection makes clear, the overwhelming preponderance of studies have found that cell phone radiation, even at levels that are many times higher than the exposure limit for cell phones does not cause DNA damage.
Does Cell Phone EMF Damage DNA?
Recent "Positive" studies
Alarmist groups continuously promote "positive" studies (studies that find potentially harmful effects). The fact that virtually all such studies have turned out to be false positives has not changed this tactic. The recent publication of some new poorly conducted "positive" studies has not altered the scientific consensus. The following are a few quotes from the recent expert report from EFHRAM European Health Risk Assessment Network entitled: "Report on Risks of EMF in vitro and in vivo" dated July 2010.
P 16 & 17: "In the last 15 years most of the research on RF and health has been devoted to the search for non thermal biological effects of exposure. This search has been unsuccessful so far in spite of the report of many uncorrelated findings. The collection of recent papers does not change the overall picture and, on the contrary, it appears that the quality of the work in particular in terms of exposure systems and dosimetry has not been satisfactory, despite the availability of such devices and methods. Results from the high-quality studies are mostly negative".
P 27 "For the three frequency ranges examined, the conclusions of the 2009 SCENIHR report are still valid in spite of the publication of several positive findings. Many of the new publications originate from laboratories and countries that are new to bioelectromagnetics research. This translates sometimes into unsatisfactory dosimetry or statistical analysis. Health risk assessment to be performed in the coming years (e.g., WHO EMF project) will need to be carried out with strict quality criteria".
Thus despite publication of some new poorly conducted studies with "positive" results, the scientific consensus concerning the safety of EMF has not changed.
The SCENIHR is the scientific advisory body of the European Commission that provides scientific advice relating to consumer safety, public health and the environment. In Jan. 2009 the SCENIHR submitted a comprehensive 83 page report on Health Effects of Exposure to EMF. In its overall conclusion the SCENIHR states: "It is concluded from three independent lines of evidence (epidemiological, animal and in vitro studies) that exposure to RF fields is unlikely to lead to an increase in cancer in humans." This section will provide an overview of the evidence from "in vitro" studies. These are studies in which various types of cells are exposed to different levels of EMF and scientists look for possible effects.
Alarmists and a minority of scientists, whose work is not recognized according to established standards, point to some studies that have shown evidence for harm. However studies showing harm have not been replicated in follow up studies, and/or have been strongly refuted by far more comprehensive and rigorous studies. In its report the SCENIHR states: P 26 "In the majority of studies no genotoxic effects were shown. A few studies suggest various biological effects (including genotoxic effects) from RF fields, alone or in combination with other factors, mostly at higher SAR values (above 2 W/kg). The biological relevance of these findings is however unclear. Inconsistent in vitro findings and a lack of dose response relationships render any mechanistic understanding of potential non-thermal interactions between RF and living systems difficult. For RF fields below the recommended limits (2 W/kg) for energy absorption due to mobile phones, in vitro studies have not identified reproducible effects by which carcinogenicity in living systems could be explained."
The SCENIHR points out that it is imperitive that studies be conducted in a rigorous and reproducible manner. It is very easy for in vitro studies, particularly those looking for any kind of effect on cell cultures, to go wrong. This is because there are so many ways to inadvertantly affect such cultures - they are extremely sensitive to all sorts of disturbances and contaminants. The following quote from P 58 of the SCEHIHR report outlines the criteria for scientifically rigorous in vitro studies:
"In general, for toxicological studies it is imperative to set up the accurate experimental control samples. Positive and negative controls within in vitro studies provide evidence for controlled experimental conditions. In EMF research it is preferable to use sham exposure as a control condition as well, and performing experiments in a blinded manner.
Exposure has to be performed under fully controlled conditions regarding field exposure (frequency conditions, flux density, SAR-values etc.), temperature, CO2 etc. and has to be documented. Furthermore, a proper dosimetry has to be presented.
For risk evaluation, studies of dose dependency are needed to determine possible threshold values.
It is evident that the appropriate cell types have to be used for specific experimental approaches for proper identification of biological effect.
Concerning statistical power, both the number of parallel samples during the experiment and the number of independent replicates of an experiment have to be considered.
To provide information about genotoxic capacity, a battery of techniques and methods are available, ideally, the used methods should confirm and/or compensate each other. Therefore, it is necessary to prove positive findings by using different techniques (Table 2). In addition, the reproducibility of positive findings has to be shown by independent laboratories."
Based on these criteria, the SCENIHR reached the following conclusions concerning in vitro studies: P. 60 "There is no consistent indication from in vitro research that RF fields affect cells at the nonthermal exposure level." P. 61 "Furthermore, the in vitro studies regarding genotoxicity fail to provide evidence for an involvement of RF field exposure in DNA-damage." Virtually all the public health organizations of the world's industrialized countries have published statements concluding that there is no evidence of harm from EMF. These include the World Health Organization (WHO), the US FDA, the European SCENIHR and the public health organizations of more than 20 countries. In vitro studies are important because all carcinogens known to science show genotoxic effects in vitro. The failure to find scientifically credible evidence of such harm provides strong support for the safety of EMF within established limits.
Other in Vitro Studies
In this section we will describe a few other in vitro studies conducted with the kind of scientific rigor that is recommended by the SCENIHR. These studies refute the findings of earlier flawed studies.
Meta-Analysis 63 Studies
The first study is a meta-analysis (summary/overview) summarizing the results of 63 in vitro studies. The paper is entitled Genetic Damage in Mammalian Somatic Cells Exposed to Radiofrequency Radiation: A Meta-analysis of Data from 63 Publications (1990 - 2005), by Vijayalaxmi and Thomas J. Prihoda, published in Radiation Research 169 (2008). The following excerpts provide an overview of the paper and its conclusions:Abstract
"During the last several decades, numerous researchers have examined the potential of in vitro and/or in vivo exposure of radiofrequency (RF radiation to damage the genetic material in mammalian somatic cells. A meta-analysis of reported data was conducted to obtain a quantitative estimate (with 95% confidence intervals) of genotoxicity in RF-radiation-exposed cells compared with sham-exposed/unexposed control cells ..... The overall data indicated that (1) the difference between RF-radiation-exposed and sham-/unexposed controls as well as the effect size or standardized mean difference due to RF-radiation exposure was small with very few exceptions; (2) at certain RF radiation exposure conditions, there were statistically significant increases in genotoxicity for some end points; and (3) the mean indices for chromosomal aberrations and micronuclei in RF-radiation-exposed and sham-/unexposed controls were within the spontaneous levels reported in the historical database. Considerable evidence for publication bias was found in the meta-analysis."
From the main body:
"the data were skewed, indicating a significant publication bias (P < 0.0001) toward positive publications even with small sample sizes, while negative papers were published only when the sample size was large." "Finally, since the meta-analysis strongly suggested the presence of publication bias, conclusions drawn from it should be regarded as tentative."
These conclusions are very significant. The differences in genotoxicity between sham and control cell cultures were generally small and within the bounds of historical statistical variability. In other words, the results of most of the studies were not significant. However, the most important statement here is that "considerable evidence for publication bias was found". This means that researhers rushed to publish results that seemed to find genotoxic results, even if their studies were not based on large sample sizes. Studies of similar "quality" that did not find genotoxic results were relatively absent. This indicates "publication bias".
Heat Shock Proteins
Continuous Wave and Simulated GSM Exposure at 1.8W/kg and 1.8 GHz do not Inducehsp16-1 Heat-Shock Gene Expression in Caenorhabditis elegans by Adam S. Dawe, et al. published in Bioelectromagnetics 29:92-99 (2008). This is a study of the expression of heat shock proteins in the cells of the worm C. elegans. Heat shock proteins are produced when cells are exposed to elevated temperatures or other stress factors such as such as infection, inflammation, exposure of the cell to toxins (ethanol, arsenic, trace metals and ultraviolet light, among many others), starvation, hypoxia (oxygen deprivation), nitrogen deficiency (in plants), or water deprivation. A number of previous studies had been done which detected the expression of heat shock proteins when cells of C elegans were exposed to EMF from mobile phones. If valid, these "positive" results could indicate that the EMF was causing stress to the cells. This study set out to reproduce these results using higher levels of EMF, a much more advanced apparatus that guaranteed uniformity of exposure, the most "sensitive" heat shock protein, and a double blind protocol with both real and sham exposure. The overall conclusion was: "For both continuous wave (CW) and Talk-pulsed RF exposures (2.5 h at 25 8C), there was no indication that RF exposure could induce reporter expression above sham control levels. Thus, at much higher induced RF field strength (close to the maximum permitted exposure from a mobile telephone handset), this particular nematode heat-shock gene is not up-regulated." In other words, this highly rigorous study failed to find any effect on heat shock proteins at much higher levels of EMF than previous "positive" studies.
Analysis of gene expression in two human-derived cell lines exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field
Vinita Chauhan et al. Proteomics 2007, 7, 3896-3905. Gene expression is a highly sensitive measure of the activity of cells. Cells respond to any significant changes in their environment or health through gene expression. This study used the latest high throughput screening technology to monitor the expression of thousands of genes on cell cultures that were exposed to cell phone EMF. It set out to reproduce the results of earlier studies of gene expression, some of which had produced "positive" results. If valid, these "positive" results could indicate that the EMF was affecting the cells and causing them to react. This study used a rigorous experimental protocol with the most advanced equipment to assure uniform exposure, the latest DNA microarray "chips" to monitor the expression of 22,000 genes simultaneously, several different types of cell lines, several different exposure levels including levels well in excess of cell phone maximums, a double blind protocol which included "sham" exposure (negative control) as well as a heat shock exposure (positive control). The experiments were independently repeated five times. The conclusion of this study states: "In conclusion, we found no significant changes in gene expression in glioblastoma and monocytic cells resulting from 1.9 GHz RF field exposures. Most studies to date that have reported differential gene expression following RF field exposure do not adhere to many of the most fundamental aspects of well-designed microarray studies. As a consequence, the conclusions reached in those studies must be interpreted with caution as a result of serious shortcomings in the experimental design and statistical analysis of the microarray data. Future well designed high-throughput genomics and proteomics studies may assist in the evaluation of possible nonthermal bioeffects from RF field exposure." In other words, this highly rigorous study failed to find any effect on gene expression using the most advanced technology at much higher levels of EMF than previous "positive" studies.
COMAR TECHNICAL INFORMATION STATEMENT: EXPERT REVIEWS ON POTENTIAL HEALTH EFFECTS OF RADIOFREQUENCY ELECTROMAGNETIC FIELDS AND COMMENTS ON THE BIOINITIATIVE REPORT by The Committee on Man and Radiation (COMAR)* Health Physics: October 2009 - Volume 97 - Issue 4 - pp 348-356. In its report on EMF and Health the SCENIHR had the following to say about studies of possible DNA damage in cell cultures exposed to EMF. P. 61 "Furthermore, the in vitro studies regarding genotoxicity fail to provide evidence for an involvement of RF field exposure in DNA-damage."
On this point, alarmists have cited flawed studies that claimed to have found evidence of DNA damage with in virtro studies. The studies in this area have recently been reviewed in an overview paper by the COMAR committee of the IEEE. The following are excerpts from their report. Note that in this analysis, COMAR provides a critique of the flawed studies cited in the alarmist Bio-Initiative Report.
"Some of the evidence for the BIR (Bio-Initiative Report) conclusion was based on the results of Lai and Singh (1995, 1996), who reported DNA breaks in the brain cells of rats exposed to RF energy (BIR 2007, Section 6), and on the results from Rudiger's lab showing DNA breaks in cells cultured in vitro (Diem et al. 2005; Schwarz et al. 2008; BIR, Section 1, p. 17). Follow-on research to the Lai and Singh reports at another university included an extensive study comparing different DNA damage methods and included an attempt at exact replication of the original studies; the results failed to demonstrate an increase in DNA damage due to RF exposure (Lagroye et al. 2004). Other research (Malyapa et al. 1997) also failed to confirm DNA damage. The Stewart Report concluded that the evidence of Lai and Singh for DNA damage "is contradicted by a number of other studies in vivo and is not supported by in vitro work" (IEGMP 2000, Paragraph 5.134, page 70).
The in vitro results published by Rudiger's lab could not be confirmed by an independent lab that attempted an exact replication (Speit et al. 2007). More recently, Rudiger's results have been the subject of a scientific misconduct investigation that revealed that some of the data used in at least one publication by the group had been fabricated (Vogel 2008)."
In other words, a series of follow up studies using much more rigorous methodology failed to find any evidence for DNA damage. At least one of the previous "positive" studies contained evidence of alleged scientific fraud.
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