Scientific Progress - Wireless Phones and Brain Cancer: Current State of the Science

The current science is not definitive about health risks from wireless phones; however, the legitimate questions about safety that have arisen from recent studies make claims of absolute safety no longer supportable. Objective: The objective of this paper is to outline for primary care providers the results of the most current research on the possible impact of wireless phone use on human health. Presented are study results from Wireless Technology Research (WTR) program, the 7-year, $27 million effort funded by the wireless industry in the United States, that represents the world's most comprehensive research effort addressing this issue to date. Science-based recommendations for consumer interventions and future research are presented.

Original studies performed under the WTR program as well as other relevant research from around the world. Study Selection: This article presents a synopsis of the peer-reviewed in vitro and in vivo laboratory research, and the peer-reviewed epidemiology studies supported by the WTR, as well as a summary of other relevant work. Data Extraction: Only peer-reviewed scientific studies are presented, primarily WTR-sponsored research. In addition, results of the WTR literature surveillance program, which identified other relevant toxicology and epidemiology studies on an ongoing basis, are presented. These studies are presented in the context of their usefulness in providing intervention recommendations for consumers.

Following a qualitative synthesis of specific relevant non-WTR research and a critical assessment of the WTR results, the following represents the current state of scientific understanding relevant to the public health impact of wireless phones: laboratory studies appear to have confirmed that radio frequency radiation from wireless phone antennas is insufficient to cause DNA breakage; however, this same radiation appears to cause genetic damage in human blood as measured through the formation of micronuclei. An increase in the rate of brain cancer mortality among hand-held cellular phone users as compared to car phone users, though not statistically significant, was observed in the WTR cohort study. A statistically significant increase in the risk of neuro-epithelial brain tumors was observed among cellular phone users in another case-control study.

As new data emerge, our understanding of this complex problem will improve; however, at present there is a critical need for ongoing and open evaluation of the public health impact of new science, and communication of this science and derivative intervention options to those who are potentially affected.

Regulatory and Public Health Context The immense popularity of the wireless phone and the continued worldwide growth of the wireless phone industry have created a unique challenge for physicians and other care providers entrusted with patients' health. While scientific information currently available is unclear about safety, in the United States there are currently more than 90 million wireless phone subscribers, with thousands more people each day taking up the wireless phone.[1] Worldwide, there are an estimated 400 million users[2] (see Figure 1).

As we approach the second decade of the penetration of wireless phones into society, regulatory controls on wireless technology are variable across the world. The situation in the United States is illustrative of the regulatory confusion. For example, in the United States, there are no measures regulating potential wireless phone health effects.[3] Neither the Federal Communications Commission (FCC), responsible for the regulation of the commercial aspects of wireless technology, nor the U.S. Food and Drug Administration (FDA), responsible for requiring premarket testing and postmarket surveillance of radiation-emitting devices in appropriate circumstances, has taken consumer protection steps.[4]

In the mid-1990s, the FCC established guidelines for wireless phone emissions, but the FCC maintains that the guidelines are not safety regulations because the FCC is not a health and safety agency. Prior to the implementation of the current guidelines, wireless phones were expressly exempted from emission guidelines because it was believed that they operated at power levels too low to cause adverse health effects, the so-called low power exclusion.[5] The FDA has issued informational papers for consumers, but outside of their regulatory framework. Recently, the FDA and the industry's top trade association have entered into a cooperative research agreement that has come under criticism for its apparent conflict of interest. The role of the Environmental Protection Agency, an important regulatory presence regarding radio frequency radiation at the beginning of the decade, has been reduced and is currently undefined.

Worldwide, similar situations exist, where the implementation of consumer protection steps have been slow and industry involvement in research and public policy decisions borders on control.

Since early 1993, questions about cell phone safety have been raised in both scientific circles and the popular media.[6,7,8,9,10,11,12] Congressional hearings in the United States during 1993 and a decision by a Florida court in 1994 highlighted the dearth of scientific information relevant to wireless phone safety at the time.[11,12] Indeed, the paucity of data upon which informed judgments about health risk could be made led to the sponsorship by the wireless industry of the unprecedented independent surveillance and research effort that has spawned the majority of the science we now have to shed light on this important public health issue.[13]

With scientific uncertainty, limited research follow-up under way, and minimal government oversight, consumers and those they trust most about their health -- their physicians -- are left to fend for themselves in this regard. The scientific information now in hand will be the basis for health protection for the foreseeable future, and it is critical that primary care providers are aware of both the changing science and consumer options so that informed recommendations can be made.

The Current Science Wireless phones fall broadly into 2 categories: cellular phones and personal communication system (PCS) phones. Both technologies employ radio frequency radiation (RFR) at a specific wave frequency to transmit voice messages via an antenna located on the phone. Cellular phones operate at between 824-894 megahertz (MHz) and emit either analog or digital signals. Analog phones produce a signal whose strength or frequency can vary over a defined range, but whose wave is continuous. With analog phones, voice messages are sent by varying either the wave's height or the number of waves per second. Digital phones produce a signal whose strength or frequency can vary in discrete steps. With digital technology, voice messages are sent in a series of rapid bursts or pulses to enable a greater density of users. Digital waves are pulsed. PCS phones in the United States operate in the 1800-2000 MHz range, and are primarily digital. Global System Mobile (GSM) is the digital standard that operates worldwide outside of the United States. From a public health perspective, the signals from each of these technology types are more similar than different in terms of biological impact.[14]

The first questions about the potential for cellular phones to cause brain cancer were raised in 1993. The clinical observation by a Florida neurologist, Dr. David Perlmutter, that his patient's brain tumor was located in an area where RFR from her cellular phone's antenna would be deposited, made international news after he aired his hypothesis, on CNN's Larry King Live television show, that use of the phone caused the tumor (Perlmutter D, personal communication). Biological bases for Perlmutter's hypothesis were derived from studies conducted by Dr. Stephen Cleary of the Medical College of Virginia, Richmond, showing a proliferation of tumor cells cultured in vitro following exposure to radio frequency radiation (RFR).[15,16]

At that time, most scientists believed that the low power pushing cellular phone signals was insufficient to cause heating of biological tissue, the only known mechanistic underpinning of RFR damage. The combined observations of Perlmutter and Cleary were met with skepticism. Because Dr. Cleary was not able to quantify the degree of heating in his experimental system, scientists believed his findings were artifacts due to the uncontrolled heating of the tumor cells.[17] Without a biological basis, the observation by Dr. Perlmutter that the tumor in his patient was proximal to the area exposed to RFR from the cell phone antenna was considered by many to be an artifact as well. Nonetheless, these observations raised questions that confused the public and alarmed the Congress, and led to the ambitious $27 million dollar surveillance and research effort funded by the wireless industry, later known as the Wireless Technology Research (WTR) program.[13]

In late 1994, Lai and Singh reported on their observation that rats whose whole bodies were exposed to microwaves similar in intensity to those radiating from a cellular phone antenna appeared to experience single-strand DNA breakage as a result of the exposure. The following year they published a similar report suggesting double-strand DNA breaks in the same exposure scenario. Lai and Singh had adapted the traditionally in vitro single-cell gel (SCG) assay to an in vivo situation. This adaptation had not been validated in other laboratories, so interpretation of these findings with respect to scientific validity was difficult.[18,19,20,21,22,23,24,25,26,27] In addition; the whole body microwave (2450 MHz) exposure approach of the investigators was sufficiently different from actual human cell phone exposure (ie, head only) to render their results not interpretable with respect to human cell phone usage.[28,29,30,31,32,33,34] Further, studies of the dosimetry of cell phone emissions suggested that the antenna from a cellular phone would emit insufficient energy to break the base pair bonds holding DNA together, thus casting further doubt on the relevance of these findings to human cellular phone usage. During the ensuing 2 years, spurred on in part by the perceived shortcomings of these earlier studies, scientists pursuing biological effects focused on the development of both in vitro and in vivo exposure systems that were capable of providing information directly relevant to humans using wireless phones[35,36,37,38] (Lee PS. Evaluation of radiofrequency radiation (RFR) in the L5178Y mouse lymphoma cell tk+/--tk-/- gene mutation assay. Submitted for publication). These focused efforts included adaptations that provided for uniform fields of exposure and heating controls for in vitro experiments and head-concentrated exposures for experiments using animals. With these new and directly relevant exposure systems now available, subsequent findings had to be looked at more seriously with respect to human health risk.

In 1997, Adey and colleagues[21] were the first to report biological effects in rats exposed head first to cellular phone-mediated RFR. While these data did not indicate a hazard from the RFR exposure, indeed they suggested a protective effect against tumors; this represented the first well-controlled study showing biological effects from RFR exposure that were not heat induced.

Later in the same year, Repacholi[39] reported that genetically engineered mice (in this case, specific mice that are predisposed to malignant tumor formation at an increased rate) exposed whole body to RFR exhibited an increase in lymphoma. Repacholi's findings were met with skepticism because it was unclear what dose of RFR the mice in the experiment sustained, and thus, relevance to humans using wireless phones was unclear. In addition, the tumor excess he observed occurred near the end of the life expectancy of the mice, at around 18 months, and the transgenic model employed was traditionally used for only a 6-month exposure.[40,41]

Worldwide, several in vitro and in vivo experiments have been published addressing potential biological effects from wireless signals. Table 1 presents an overview of the most recent laboratory research and Table 2 summarizes the most recent epidemiology. One epidemiology study published after this table was created is a Motorola-funded study conducted by Morgan and associates.[42] This study does not support an association between occupational RF exposure and brain cancers or lymphoma/leukemia. Exposure was measured qualitatively through the use of job titles to create a job exposure matrix. While occupational studies are informative, this study could not address real-life exposure from cellular telephones and is thus limited in its generalizability.

It is important to note in reviewing these data that only the WTR-sponsored studies presented herein employed the exposure systems developed specifically to allow extrapolation of results from experimental systems to people using wireless phones.

The Structure of the WTR Program The 7-year WTR program, established to provide objective scientific information upon which to base public health decisions regarding wireless phones, encompassed independent peer review coordinated through the Harvard Center for Risk Analysis at the Harvard School of Public Health, strict adherence to both Good Laboratory Practices (GLP) and Good Epidemiology Practices (GEP), and the input of over 100 scientists and physicians worldwide. In its implementation, the WTR program rigorously adhered to a peer-reviewed research agenda that was 18 months in the making.[13]

Protocols for each study were peer reviewed prior to implementation, and progress in the field was regularly reviewed by the U.S. government's Interagency Working Group on RFR, which included representatives from the FDA, FCC, Environmental Protection Agency, National Cancer Institute, National Institute for Occupational Safety and Health, and the National Institute of Environmental Health Sciences. In addition to peer review, a requirement for all investigators was that their findings also be submitted for publication in the open scientific literature.

For decisions about health impact, the WTR program employed a public health paradigm, consistent with the regulatory framework for postmarket surveillance for medical devices and pharmaceuticals. Within that framework, each of the more than 50 studies conducted with WTR support were judged by the aforementioned groups in terms of whether or not the findings indicated a public health problem, ie, a positive finding, that warranted public health intervention[43] (see Figure 1). As a result, decisions about risk and intervention could be made with confidence prior to study findings appearing in the open scientific literature, a process that could take months if not years. With thousands more people being exposed to wireless phones every day, it was determined that time expediency in applying the findings of this important research was of critical importance. Further, this is the same paradigm that federal regulatory agencies would use to intervene if they were engaged, ie, decision making about public health impact after peer review but prior to publication.

Thus, each of the studies reported here has been peer reviewed both at the protocol stage and after the final report and conclusions were drawn. Each report is publicly available through the WTR, or published in or submitted to the peer-reviewed scientific literature.

WTR Program Findings Findings from the WTR program began to emerge during the latter part of 1998 and the beginning of 1999. With the newly developed in vitro and in vivo exposure systems specifically designed for extrapolation to human wireless phone usage, and the first epidemiology studies looking at health risks among cellular phone users, the WTR research added much needed perspective to the questions raised by previously published work. Tables 3 and 4 present results from those studies performed under the WTR program.

WTR-sponsored studies addressing genetic damage from wireless phone exposures were conducted simultaneously at 2 GLP facilities, Integrated Laboratory Systems in Research Triangle Park, North Carolina and Stanford Research Institute in Palo Alto, California. Repetitions of the experiments were included in the peer-reviewed protocols along with independent quality assurance audits consistent with GLP procedures.

In vitro assays of bacteria, mouse lymphoma cells, and human lymphocytes, and in vivo studies of rats exposed head only to all types of wireless phone signals -- cellular analog, cellular digital, and 1900 MHz digital -- appear to confirm that RFR energy of the magnitude associated with wireless phones was insufficient to cause breakage of DNA[18,44] (Donner EM. In vitro chromosome aberration assay in human blood lymphocytes exposed to 1909.8 MHz radiofrequency (RF) signals generated by personal communication systems (PCS) technology; Donner EM. In vitro chromosome aberration assay in human blood lymphocytes exposed to voice modulated 837 MHz radiofrequency (RF) signals generated by time division multiple access (TDMA) technology; Donner EM. Salmonella typhimurium/Escherichia coli reverse mutation assay with 1909.8 MHz radiofrequency (RF) signals generated by personal communication systems (PCS) technology; Donner EM. Salmonella typhimurium/Escherichia coli reverse mutation assay with 837 MHz radiofrequency (RF) signals generated by code division multiple access (CDMA) technology; Donner EM. Salmonella typhimurium/Escherichia coli reverse mutation assay with voice modulated 837 MHz fields generated by analog technology; Donner EM. Salmonella typhimurium/Escherichia coli reverse mutation assay with voice modulated 837 MHz radiofrequency (RF) signals generated by time division multiple access (TDMA) technology; Bakke J, Winegar RA. Evaluation of radiofrequency radiation (RFR) in the human peripheral lymphocyte chromosome aberration assay; Riccio E. Evaluation of radiofrequency radiation (RFR) in the Salmonella Escherichia Coli assay. SRI International; Tice R. Mouse lymphoma mammalian mutagenesis assay with voice modulated 837 MHz radiofrequency signals generated by time division access (TDMA) technology; Submitted for publication.).

However, a series of studies addressing genetic damage to human blood cells through the assessment of micronucleus formation were unequivocally positive for all cellular and PCS phone technologies[45,46,47,48] (Donner EM. Chromosome aberration assay in human blood lymphocytes exposed to voice modulated 837 MHz RF fields generated by analog technology; Donner EM. In vitro chromosome aberration assay in human blood lymphocytes exposed to 837 MHz radiofrequency (RF) signals generated by code division multiple access (CDMA) technology; Tice R. DNA damage in brain cells of male rats exposed to voice modulated 837 MHz radiofrequency fields generated by analog technology; Tice R. Evaluation of analog radio frequency signals using the mouse lymphoma mammalian mutagenesis assay; Tice R. Evaluation of analog radiofrequency signals using the leukocyte single cell gel and lymphocyte binucleate micronucleus assays; Tice R. Evaluation of analog radiofrequency signals using the leukocyte single cell gel and lymphocyte binucleate micronucleus assays-24 hour exposure; Tice R. Leukocyte single cell gel and lymphocyte binucleate micronucleus assays using human blood exposed to 837 MHz radiofrequency signals generated from code digital multiple access (CDMA) technology; Tice R. Leukocyte single cell gel and lymphocyte binucleate micronucleus assays using human blood exposed to voice modulated 837 MHz radiofrequecy signals generated from time division multiple access (TDMA) technology; Tice R. Mouse lymphoma mammalian mutagenesis assay with 1909.8 MHz radiofrequency signals generated by personal communication systems (PCS) technology; Tice R. Mouse lymphoma mammalian mutagenesis assay with 837 MHz radiofrequency signals generated by code division multiple access (CMDA) technology; Lai H, Singh NP. DNA single-strand breaks in brain cells of rats acutely exposed to a voice-modulated analog 837-MHZ radiofrequency (RF) signal. Submitted for publication.).

The increase in the number of cells with micronuclei associated with RFR exposure suggests an impairment of the ability of the human blood cells to repair broken DNA. Multinucleated cells can reproduce and lead to proliferation of damaged blood cells. Repeated studies confirmed that the observed effects could not be explained by heating in the experimental system or any other artifact. It is important to note that impairment of DNA repair as the genotoxicity mechanism is consistent with the earlier findings of Lai and Singh, and other investigators have reported this type of genetic damage for RFR in general. The conclusion of the investigators was that under these experimental conditions, the RFR from the wireless phone is genotoxic.[49]

WTR-sponsored epidemiology studies do raise some questions about health risks associated with cellular phone usage. PCS and digital signaling in the cellular frequency bands were not covered in these studies because those technologies were not in widespread use when the studies were conducted. While none of the WTR epidemiologic studies taken alone are persuasive with respect to a definitive public health threat from cellular phone use, these data, supported by the biological plausibility suggested by the positive genetic damage assays, suggest that there could be a pattern of public health risk emerging.[50]

Dreyer and colleagues[51,52,53] (Dreyer NA, Loughlin JE, Rothman KJ. Cause-specific mortality in cellular telephone users. 1999. manuscript in preparation.) completed the largest cohort study to date of analog cellular phone users and found an increase in the rate of brain cancer mortality in hand-held phone users (near field exposures) as compared with car phone users with the antenna on the rear window (far field exposures). The rate of brain cancer death was more than 3 times greater in the hand-held phone group compared with the far field control group; however, since the total number of persons in this group was small and the follow-up period was short (1 year), the difference was not statistically significant.

A study by Muscat and colleagues addressing primary brain cancer is suggestive of a potential risk.[54] This case-control study accrued newly diagnosed cases from 5 hospitals across the United States and was designed to look at both duration and frequency of cellular phone usage. When all primary brain cancer cases and controls were included in the analysis, there was no evidence of increased risk of primary brain cancer associated with cellular phone use history. However, the majority of the brain cancers included in the study were outside of the 2- to 3-inch exposure pattern generally accepted as the depth of RFR penetration from a wireless phone. A histopathologic subtype analysis segregating neuro-epithelial tumors likely in range of the RFR exposure revealed a statistically significant increase in risk associated with cellular phone use. Further, those patients who reported using their phone on the right side of their head had a significant increase in tumors on that side of the head. This finding of laterality was consistent with the observations of Hardell[55] who, in a case control study conducted in Sweden, observed that tumors were more frequently found on the side of the head where the phone was used.

The study by Muscat and coworkers was able to control for factors that may affect cell phone use, such as age and socioeconomic status (SES). Differences in age were accounted for by using age-matched controls, and SES was controlled for in the statistical models by controlling for education.

Currently, the necessary consumer protection and scientific follow-up derivative of the work completed to date is not in place. This lack of clarity in the science is greatly emphasized as a result of the explosion in wireless technology usage across the globe. Recent advertising trends by the wireless industry targeting children, including wireless phones adorned with pictures of Disney characters such as Mickey and Minnie Mouse, are of special concern.[56,57,58] Recent work by Gandhi[59] at the University of Utah shows that penetration of RFR into the heads of children is greater than in adults. Growing mitotic cells in children could be at higher risk for functional genetic damage such as that found in the WTR studies of exposure to RFR.

The first step in empowering physicians to help their patients who are concerned is communicating the current state of knowledge regarding these potential health impacts, as uncertain as they are. Because there are interventions available to minimize exposure to RFR from the wireless phone antenna, patients can then have choices with respect to minimizing their exposure.[60,61]

Many of the models of wireless phones currently available are equipped with headsets and hands-free devices that allow for the phones to be used without the antenna being placed close to the head.

Pagers are available that allow for 2-way messaging similar to wireless phones, but without the concentrated RFR exposure from an antenna placed near the head. Pagers are preferable for young children and teenagers whose tissues are still developing.

Shields are being developed that theoretically limit radiation exposure to the body. A panel of experts in the United Kingdom, chaired by Sir William Stewart, issued a report in May 2000 that recommended children younger than 16 years of age should be discouraged from using mobile phones.[62] The report claims that children are likely to be more vulnerable to any unrecognized health risks from mobile phone use than are adults. "The rationale is as follows: the developing nervous system is likely to be more vulnerable than the mature nervous system to potentially hazardous agents because of their smaller heads, thinner skulls and higher tissue conductivity, children may absorb more energy from a given phone than do adults

if there are detrimental health effects caused by mobile phone signals, those using phones for a longer period of their lives will tend to accumulate a greater risk."

The justification for suggesting that persons under age 16 are at greater risk is as follows: development of the head and nervous system is generally complete by age 16 years. For example, the density of synapses reaches adult level around puberty, and skull thickness and brain size reach adult levels around age 14 or 15. According to the report, "Sixteen is usually recognized as the age at which individuals are sufficiently mature to make informed choices about other 'adult' activities."

The science is not clear enough to enable us to make informed judgments about how wireless phone usage patterns affect health. Studies completed to date do not allow us to distinguish, in terms of health risk, the differences among various patterns of usage. We do not know, for example, whether one 10-minute phone call is better or worse than ten 1-minute phone calls with respect to health impact. We know that the intensity of the RFR exposure is greatest during dialing and ringing, and that the amount of RFR necessary to sustain a call lessens during the call.[13] However, it is premature to speculate that lessening the length of calls, for example, lessens potential health impact. Similarly, it is premature to recommend that lessening the number of calls accrues any health benefit.

Options to reduce exposure to potential harmful RFR and thus reduce the risk of health problems are available, through the efforts of wireless phone manufacturers and other providers of radiation protection devices. However, the scientific bases underlying these potentially protective devices are presently unclear. Because testing of these devices is under way, neither the government nor the industry has pushed the devices in the marketplace, and appropriately so.

The state of our knowledge with respect to meaningful public health intervention with regard to wireless phone usage is qualitative. Moving the antenna beyond the distance threshold of 2-3 inches away from the body is the only science-based recommendation that can be supported by existing data.

Important Scientific Follow-up (Tier III) Taken together, the WTR research findings are not conclusive with respect to an increased risk of brain cancer or benign tumors associated with wireless phone usage. Indeed, these findings could be chance occurrences and should be confirmed. Alternatively, these findings could be early indications of a serious public health problem; thus, an immediate and focused follow-up is clearly necessary.[50,63]

A passive reporting system to capture health complaints among wireless phone users needs to be established. Currently there is no mechanism in place to allow an assessment of the presence or absence of clusters of disease among wireless phone users.

The analog phone user cohort studied by Dreyer and associates included mortality follow- up for only 1 year, 1994. This study should be updated with analysis of mortality among the cohort members for the years 1995 through 1999.

A similar cohort for digital phone users should be established and followed, with distinctions between cellular and PCS signaling included. Cellular phones transmit in the 800-900 MHz range, whereas PCS phones transmit in the 1900 MHz range.

A WTR-coordinated tissue panel recommended that along with brain cancer, and salivary gland tumors, adult-onset leukemia should be looked at as an outcome potentially related to RFR exposure. In adults, the flat bones of the skull contain active marrow and are in range of exposure to RFR from a wireless phone's antenna.

Specific studies of children are warranted for all health outcomes relevant to the range of RFR exposures and the target tissues expected from wireless phone use among children.

Studies of the impact of RFR exposure on pregnant women, specifically the developing embryo and fetus, are warranted based on the questions raised by the existing science.

The appropriateness of the Specific Absorption Rate (SAR) as a measure indicative of nonthermal and chronic health effects is being evaluated anew. Scientists, including those at the FDA, recognize that the distinctions among thermal and nonthermal effects, and acute and chronic effects, must be addressed in subsequent research. As a measure of the rate of RFR passing through a tissue at a given time, the SAR does not have properties amenable to the evaluation of cumulative RFR exposures that could be critical to both heating and chronic exposures.

As new data become available, our understanding of this complex problem will improve; however, the explosion of this technology in society creates a unique necessity for ongoing interpretation of the science and communication of intervention options to those who are potentially affected and concerned. Consumers should be given the opportunity to know what potential risks they are likely to incur with the use of this technology and should have the opportunity to make informed judgments about the assumption of that risk.

A 40-Year-Old Man With Painful, Rupturing Lesions

A 40-year-old man presents with a 20-year history of recurrent painful nodules on his bilateral buttocks, gluteal cleft, and medial aspect of his upper thighs. The lesions often spontaneously rupture and result in sinus tracts or scarring

I wonder how many mice and other animals have been exposed to the frequencies used in transmissions.

Frequencies below ultraviolet, x-rays, cosmic rays do not bust up molecules which leads to cancer.

The cellular phone frequencies are way, way, way below ultraviolet. They’re below visible light, infrared, microwaves.

The highest frequency involved in cellphone communication is that of the carrier wave. The carrier wave is “modulated” to make it contain the information that is sent.

For instance, if you tune to a 103.9 FM radio station, the 103.9 is the carrier frequency. The audio is added to it resulting in a group of frequencies all very close to 103.9.

Digital information is added to a carrier also, but the carrier is still an analog signal (a near sine wave) with a small frequency spread.

Thus I don’t see how digital information conveyed on a carrier wave is going to produce high frequency signals that are known to be damaging.

Getting back to the research described, what about mice being subjected to strong sub-ultraviolet radiation. Has that not been done? I’m sure it has, and have we heard of the mice having ill effects? Not me.

Radio effects below UV seem to be related only to tissue heating. Maybe there is something else happening with the shorter wavelengths that have yet to be identified. I do recall that an antenna must be somewhere around 1/4 wavelength in order pick up a signal; otherwise, the wave just passes by.

They still don’t know for sure.
It needs more grant money................

Together you have provided a concise, completely accurate condensed version of this study's conclusions.

Just as are the "conclusions" of so many government-funded studies, these are not "conclusions" ... not really.

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