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TR Daily: Government: Rodent Studies Can’t Be Extrapolated to Cellphone Usage

Feb 7, 2018



Government: Rodent Studies Can’t Be Extrapolated to Cellphone Usage

TR Daily – February 2, 2018

Long-term high radiofrequency radiation (RFR) exposure to rodents resulted in significant tumors in tissues surrounding nerves in the hearts of male rats, but not female rats or mice, according to draft reports released today by the National Toxicology Program (NTP), an interagency program at the National Institutes of Health.

But the NTP stressed that because the RFR levels and exposure duration and areas exposed were much greater than people experience when they use cellphones, these and other results from the research can’t be extrapolated to human cellphone use.

“The levels and duration of exposure to RFR were much greater than what people experience with even the highest level of cell phone use, and exposed the rodents’ whole bodies. So, these findings should not be directly extrapolated to human cell phone usage,” John Bucher, an NTP senior scientist, said in a news release. “We note, however, that the tumors we saw in these studies are similar to tumors previously reported in some studies of frequent cell phone users.”

A three-day meeting to peer-review the draft reports is scheduled for March 26-28 at the National Institute of Environmental Health Sciences (NIEHS), which houses NTP, in Research Triangle Park, N.C. The deadline for parties to submit comments on the draft reports is March 12.

The Food and Drug Administration nominated the $25 million cellphone radiation research, the largest and most complex studies ever done by NTP. The FDA and the Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health also participate in the NTP. About 3,000 rodents were tested.

Mr. Bucher told reporters during a conference call this afternoon that he would not change his cellphone usage based on the results of the studies.

“This is a situation, obviously, that people are not going to be encountering in utilizing cellphones,” he said of the testing parameters. He also said that epidemiology studies “have produced conflicting evidence as to whether there are increases in brain tumors” from cellphone use, and suggested that the results released today not be taken “in isolation.”

“One needs to take into consideration all evidence before reaching conclusions about public health implications of our study,” he said. He said NTP plans to conduct follow-up testing on damage to the brain from RFR once a new testing chamber is completed, hopefully this summer.

In 2011, a working group of the World Health Organization’s International Agency for Research on Cancer (IARC) concluded that RFR emissions from mobile phones are “possibly carcinogenic to humans” (TR Daily, May 31, 2011). But the working group stressed the need for additional research.

In 2010, the 13-country multi-year, multimillion dollar Interphone project concluded (TR Daily, May 17, 2010) that “no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long-term heavy use of mobile phones require further investigation.”

Mr. Bucher explained why the researchers used RFR levels that were higher than people actually are exposed to when they use cellphones. “It’s a situation that allows us to … find the potential biological event if one is going to occur,” he said.

Under the current FCC standards, localized exposure for cellphones is limited to 1.6 watts per kilogram.

“To conduct the studies, NTP built special chambers that exposed rats and mice to different levels of RFR for up to two years. Exposure levels ranged from 1.5 to 6 watts per kilogram (W/kg) in rats, and 2.5 to 10 W/kg in mice,” NTP said in the news release. “The low power level for rats was equal to the highest level permitted for local tissue exposures to cell phone emissions today. The animals were exposed for 10-minute on, 10-minute off increments, totaling just over 9 hours each day. The studies used 2G and 3G frequencies and modulations still used in voice calls and texting in the United States. More recent 4G, 4G-LTE, and 5G networks for streaming video and downloading attachments use different cell phone signal frequencies and modulations than NTP used in these studies.”

The NTP noted that cellphones “typically emit lower levels of RFR than the maximum level allowed,” and Mr. Bucher said newer wireless systems generally operate at lower emission levels.

“The incidence of tumors, called malignant schwannomas, that were observed in the heart increased in male rats as they were exposed to increasing levels of RFR beyond the allowable cell phone emissions,” the NTP noted in its news release. “Researchers also noted increases in an unusual pattern of cardiomyopathy, or damage to heart tissue, in exposed male and female rats. Overall, there was little indication of health problems in mice related to RFR.

“The reports also point out statistically significant increases in the number of rats and mice with tumors found in other organs at one or more of the exposure levels studied, including the brain, prostate gland, pituitary gland, adrenal gland, liver, and pancreas. However, the researchers determined that these were equivocal findings, meaning it was unclear if any of these tumor increases were related to RFR,” the news release added.

“The NTP studies also looked for a range of noncancer health effects in rats and mice, including changes in body weight, evidence of tissue damage from RFR-generated heating, and genetic damage. Researchers saw lower body weights among newborn rats and their mothers, especially when exposed to high levels of RFR during pregnancy and lactation. Yet, these animals grew to normal size,” the news release noted.

“These studies were complex and technically challenging, but they provide the most comprehensive assessment, to date, of health effects in rats and mice from exposure to RFR,” Mr. Bucher said in the news release. “Cell phone technologies are constantly changing, and these findings provide valuable information to help guide future studies of cell phone safety.”

The 381-page draft report released today on the rat studies follows the 2016 release of partial findings from that research that NTP said support conclusions of the possible carcinogenic effects of exposure to cellphone radiation (TR Daily, May 27, 2016). Mr. Bucher said the findings released today basically confirm the partial findings without going further.

“Under the conditions of this 2-year whole-body exposure study, there was some evidence of carcinogenic activity of GSM-modulated cell phone RFR at 900 MHz in male Hsd:Sprague Dawley SD rats based on the incidences of malignant schwannoma in the heart,” the report said. “The incidences of adenoma or carcinoma (combined) in the prostate gland, malignant glioma and benign or malignant granular cell tumors in the brain, adenoma of the pars distalis in the pituitary gland, pheochromocytoma (benign, malignant, or complex combined) in the adrenal medulla, and pancreatic islet cell adenoma or carcinoma (combined) may have been related to cell phone RFR exposure. There was no evidence of carcinogenic activity of GSM-modulated cell phone RFR at 900 MHz in female Hsd:Sprague Dawley SD rats administered 1.5, 3, or 6 W/kg. There was some evidence of carcinogenic activity of CDMA-modulated cell phone RFR at 900 MHz in male Hsd:Sprague Dawley SD rats based on the incidences of malignant schwannoma in the heart. The incidences of malignant glioma in the brain, adenoma of the pars distalis in the pituitary gland, and adenoma or carcinoma (combined) of the liver may have been related to cell phone RFR exposure. There was equivocal evidence of carcinogenic activity of CDMA-modulated cell phone RFR at 900 MHz in female Hsd:Sprague Dawley SD rats based on the incidences of malignant glioma in the brain and pheochromocytoma (benign, malignant, or complex combined) in the adrenal medulla.”

The report added, “Increases in nonneoplastic lesions in the heart, brain, and prostate gland of male rats, and of the heart, thyroid gland, and adrenal gland in female rats occurred with exposures to GSM cell phone RFR at 900 MHz. Increases in nonneoplastic lesions of the heart, brain, and prostate gland occurred in males, and of the brain in females exposed to CDMA cell phone RFR at 900 MHz.”

Mr. Bucher stressed that “equivocal” findings are those where researchers can’t conclude whether ailments are related to RFR.

The 270-page report on the mice tests said that “there was equivocal evidence of carcinogenic activity of GSM-modulated cell phone RFR at 1,900 MHz in male B6C3F1/N mice based on the combined incidences of fibrosarcoma, sarcoma, or malignant fibrous histiocytoma in the skin and the incidences of alveolar/bronchiolar adenoma or carcinoma (combined) in the lung. There was equivocal evidence of carcinogenic activity of GSM-modulated cell phone RFR at 1,900 MHz in female B6C3F1/N mice based on the incidences of malignant lymphoma (all organs). There was equivocal evidence of carcinogenic activity of CDMA-modulated cell phone RFR at 1,900 MHz in male B6C3F1/N mice based on the incidences of hepatoblastoma of the liver. There was equivocal evidence of carcinogenic activity of CDMA-modulated cell phone RFR at 1,900 MHz in female B6C3F1/N mice based on the incidences of malignant lymphoma (all organs). Exposure to GSM- or CDMA-modulated cell phone RFR at 1,900 MHz did not increase the incidence of any nonneoplastic lesions in male or female B6C3F1/N mice.”

Mr. Bucher said he was surprised by the discovery of malignant schwannomas and by the fact that there was a decreased survival rate of rats in the control group, which was largely attributed “to the higher severity of chronic progressive nephropathy in the kidney.”

In response to the draft reports released today, the FCC and FDA indicated they don’t believe the findings merit changes in the current RFR standards, and CTIA echoed that sentiment. But advocates for tighter standards disagreed.

“Scientific evidence always informs FCC rules on this issue,” said FCC spokesman Neil Grace. “While we have continued to follow the work of the National Toxicology Program, including today’s draft studies, we also follow the work of other experts in the United States and internationally. Specific to today’s studies, we note that the majority of the NTP tests were conducted at levels higher than permitted under the Commission’s current rules and the internationally accepted standards for cell phones and other radio devices. We will continue to follow all recommendations from the U.S. Food and Drug Administration and other federal health and safety experts, including whether the FCC should modify its current policies and RF exposure limits.”

The FCC in 2013 adopted an item opening a proceeding to explore whether it should modify its RF exposure standards (TR Daily, March 29, 2013). The review is the first time the FCC has considered whether to reexamine those standards since they were adopted in 1996.

Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, said that his agency respects the NTP research. “When we nominated this topic for study in 1999, there were limited epidemiological and long-term animal studies investigating the effects of radiofrequency energy exposure from cellular phones. Fortunately, since then, there have been hundreds of studies from which to draw a wealth of information about these technologies which have come to play an important role in our everyday lives,” he said. “Taken together, all of this research provides a more complete picture regarding radiofrequency energy exposure that has informed the FDA’s assessment of this important public health issue, and given us the confidence that the current safety limits for cell phone radiation remain acceptable for protecting the public health.”

Dr. Shuren elaborated “that based on our ongoing evaluation of this issue and taking into account all available scientific evidence we have received, we have not found sufficient evidence that there are adverse health effects in humans caused by exposures at or under the current radiofrequency energy exposure limits. Even with frequent daily use by the vast majority of adults, we have not seen an increase in events like brain tumors. Based on this current information, we believe the current safety limits for cell phones are acceptable for protecting the public health.”

He also noted that the NTP’s research used RFR levels “considerably above the current safety limits for cell phones” and he said that “the conclusions still require careful discussion, as our preliminary understanding of the NTP results is that the study found mostly equivocal, or ambiguous, evidence that whole body radiofrequency energy exposures given to rats or mice in the study actually caused cancer in these animals. There are additional unusual findings from the study, such as the exposed rats living longer than the control group rats, that we are assessing to understand how that may be relevant to the results. The FDA looks forward to participating in the peer review of this study in March, which is an important and crucial step in scientific research to assure the integrity and quality of the data and the conclusions that can be drawn from it.”

A CTIA spokesman said, “The safety of cellphone consumers is important to CTIA and the wireless industry. We follow the guidance of the experts when it comes to cellphones and health effects. We understand that the NTP draft reports for its mice and rat studies will be put out for comment and peer review so that their significance can be assessed. The scientific community will consider the NTP draft reports in the context of the many other scientific studies conducted over several decades. NTP issued partial results of its rat study in June 2016 and since then the Federal Communications Commission, the Food and Drug Administration, the World Health Organization, the American Cancer Society and numerous other international and U.S. organizations and health experts have maintained their longstanding conclusion that the scientific evidence shows no known health risk due to the RF energy emitted by cellphones. The evidence includes analysis of official federal brain tumor statistics showing that since the introduction of cellphones in the mid-1980s, the rate of brain tumors in the United States has remained stable.”

“These draft reports are bound to create a lot of concern, but in fact they won’t change what I tell people: the evidence for an association between cell phones and cancer is weak, and so far, we have not seen a higher cancer risk in people,” said Otis Brawley, chief medical and scientific officer for the American Cancer Society.

“The animals in this study were exposed at high levels for 9 hours per day. So while the link to some rare cancers are important, there is no reason to think this study reflects real life exposures,” Dr. Brawley added. “A final point to remember is that we should not base our decisions or our point of view on a single study. When deciding where the truth lies, you really need to take all the available evidence into account. And in fact, most studies looking into cell phones and cancer are negative.”

But advocates for tougher RFR standards struck a different tone.

“The NTP study is the second U.S. government-sponsored animal study that demonstrates increased cancer risk from exposure to low intensity, non-thermal levels of microwave radiation,” said Joel Moskowitz, director of the School of Public Health at the University of California-Berkeley and creator of the web site. “Our current federal guidelines for radio frequency radiation (RFR) which were adopted in 1996 were designed only to protect us from thermal levels of exposure. The federal RFR limits should be re-assessed and strengthened in light of these findings.”

Mr. Moskowitz said it is crucial for the NTP to examine “the overall tumor risk – across different types of tumors. … Years ago, the Air Force conducted a 5-year, $5 million study which found a similar pattern of low incidences of multiple types of tumors in male rats exposed to microwave radiation. When the tumor findings were combined by the Air Force researchers, the rats exposed to microwave radiation were three times more likely to get cancer than the control rats. The microwave radiation exposure in the Air Force study was much lower in intensity than the radiation in the NTP studies.”

“The NTP tested the hypothesis that cell phone radiation could not cause health effects. This hypothesis has now been disproved because partial results the NTP released last year show cell phone radiation has adverse effects. These same cells that became cancerous in rats are the same cells that are reported to turn into tumors in people in epidemiology studies of cellphone users,” said Ronald Melnick, adviser to the Environmental Health Trust (EHT) and a retired senior toxicologist who said he designed the NTP study.

“People could be receiving cell phone radiation exposures into their body that are far higher than the NTP studies,” suggested Devra Davis, president of the EHT. “Even if there are no new findings from this report,” she added, there is “more than enough scientific evidence of harm to make policy changes. This is not just about cancer, peer reviewed research has also found many other effects, including damage to brain development,” she said.- Paul Kirby,

TR Daily – February 2, 2018

 Paul Kirby

Senior Editor


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