National Toxicology Program

National Toxicology Program

UPDATE NewsletterUPDATE NewsletterJune 2016

NTP releases rodent studies on cell phone radiofrequency radiation

By Environmental Factor

Nearly 150 reporters joined a May 27 telephone press conference hosted by the National Toxicology Program (NTP) to hear about some important new study findings in rats, on cancer and cell phone radiofrequency radiation (RFR).

NTP scientists found low incidences of tumors in the brains and hearts of male rats, but not in female rats. Studies in mice are ongoing.

Previous human observational data collected in large-scale, population-based studies have found limited evidence of an increased risk for developing cancer from cell phone use.

Linked Audio

Listen to an audio recording of the May 27 telephone press conference. (1:07:04)

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Bringing findings to public’s attention

NTP Associate Director John Bucher, Ph.D., and NTP toxicologist Michael Wyde, Ph.D., who is the study director for the RFR research, provided a brief update on the findings and answered reporters’ questions, resulting in more than 1,000 stories in the press during the following days.

“Although we are only reporting rat findings from the brain and heart while we continue evaluating data from our mouse studies, we felt it was important to bring these findings to the public’s attention,” Bucher said. “The observation of low but possibly significant increases in two tumor types, which corresponded to those seen in some human epidemiology studies among the heaviest cell phone users, was unexpected and prompted us to share this information.”

The nomination to study cell phone RFR came from the Food and Drug Administration.

Three-phased study design

NTP conducted the studies in phases, including several phases to determine the correct field strengths that would not raise the animal’s body temperature. The final phase included the chronic toxicology and cancer studies, in which the rodents were exposed daily for the majority of their lifetimes, up to 24 months.

To simulate human exposure scenarios, the animals were exposed to RFR from the two technologies and frequencies widely used in the United States — Code Division Multiple Access (CDMA) and Global System for Mobile communications (GSM) — at frequencies of 900 and 1,900 megahertz.

They were exposed for 10-minute on, 10-minute off increments, totaling a little more than nine hours a day from before birth through two years of age. These RFR exposures are higher than what most people are exposed to by cell phones.

Sharing findings with regulatory agencies

NTP has provided these findings to its federal regulatory partners so they will have the latest information for public health guidance about safe ways to use cellular telephones and other RFR emitting devices.

NTP continues to brief additional stakeholder and scientific groups. In June, Wyde will travel to Belgium to share these findings with scientists attending one of the world’s largest bioelectromagnetic conferences, BioEM2016.

The complete results from all the rat and mice studies will be available for peer review and public comment by the end of 2017.

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Director of Office of Liaison, Policy, and Review and Editor-in-Chief: Mary Wolfe | Managing Editor: Anna Lee Mosley