Cell phones utilize a specific type of radio waves, or radio frequency radiation (RFR), to transmit voice and data between the devices and the network. Exposure of people to RFR occurs primarily through use of cell phones and other wireless devices. We studied the effects of nearly lifetime exposure to two different types, or modulations, of RFR (GSM and CDMA) used in cellular telephone networks in the United States in male and female rats and mice to identify potential toxic or cancer-related hazards.Over the years, cell phone technology has evolved from the original analog technology (1G) commercially introduced in the 1980s to digital networks that supplanted analog phones. The digital network, referred to as 2G or the 2nd generation of technology, was commercially launched in the 1990s, with 3G and 4G subsequently deployed in the intervening years. When the current studies were being designed, 2G technology was the industry standard, and 3G technologies were under development. While newer technologies have continued to evolve, it is important to note that these technologies have not completely replaced the older technologies. In fact, today’s phones are very complex in that they contain several antennas, for Wi-Fi, GPS, 2G/3G bands, etc. The results of these studies remain relevant to current exposures, although the power levels of the exposures were much higher than typical patterns of human use.
We exposed groups of 90 male and 90 female mice to 2.5, 5, or 10 W/kg RFR that was modulated in the same manner in which signals are emitted from cell phones and other similar wireless communication devices. Other groups of male and female mice housed in the same type of chamber without any exposure to RFR were used as the controls. Animals were exposed to RFR for approximately 9 hours a day, 7 days per week, for 2 years. Tissues from more than 40 sites were examined for every animal.
There were higher rates of survival in males at the low (2.5 W/kg) and mid (5 W/kg) exposures to CDMA- and GSM-modulated RFR, respectively. Body weights in the exposed groups of animals were similar to their controls. In both studies (GSM and CDMA), there were higher incidences of malignant lymphoma in all groups of female mice exposed to RFR compared to controls. However, the incidences in all of the exposed females were within the range historically observed in this strain of mouse in other NTP studies. There were higher incidences of skin and lung tumors in males exposed to the highest two levels of GSM-modulated RFR (5 and 10 W/kg), and of liver tumors at the mid-dose (5 W/kg) of CDMA-modulated RFR.
For GSM-modulated RFR, we conclude that exposure to RFR may have caused tumors in the skin and lungs of male mice and malignant lymphomas in female mice. For CDMA-modulated RFR, we conclude that exposure to RFR may have caused tumors in the liver of male mice and malignant lymphomas in female mice.