The suspicion that cell phone use can cause cancers and other tumors has been under discussion for some time. Suggested have been possible associations between cell phone use and conditions including malignant gliomas and nonmalignant meningiomas, both tumors formed in the brain, and benign acoustic neuromas, slow-growing tumors that develop on the main nerve leading from the inner ear to the brain. Studies to try to find evidence of this have been conducted, and more are in progress, but so far, experts disagree about the findings.
“Numerous studies have been conducted with conflicting results, but the general consensus is that the majority don’t show convincing evidence of a correlation between cell phone use and cancer,” says Larry Junck, a University of Michigan neurologist and expert in treating and researching gliomas. However, he adds, some studies do show “a hint of a glimmer of a risk,” indicating that additional research is warranted.
Cell phones emit radiofrequency (RF) energy, a form of electromagnetic radiation. There are two kinds of electromagnetic radiation: ionizing, or radiation that can cause changes to the molecular structure, particularly DNA, sparking genetic mutations that affect the function and metabolism of a cell; and non-ionizing radiation that has lower energy and is generally assumed to be less harmful unless exposure at high levels is prolonged. Cell phones emit non-ionizing radiation, as do microwaves, cordless phones, smart meters and Wi-Fi devices, with the level of cell phone emissions falling somewhere in the middle.
“The fundamental question is: How could non-ionizing radiation can cause cancer?” says Jonathan Samet, chair of the Department of Preventive Medicine at the University of Southern California.
RF waves from cell phones come from the antenna located in the back of the device. The closer that antenna is to the head, the greater the exposure to RF energy. The body tissue closest to the phone will absorb the most energy, and the energy absorbed drops off sharply as distance increases. But many factors determine the amount of radiation exposure, such as the amount of time spent on the phone, the phone’s distance from the head, the distance to the nearest cell phone tower and the amount of power being used.
The specific absorption rate (SAR), the amount of RF energy absorbed from a cell phone into the body, varies depending upon the phone, and manufacturers are required to report the maximum SAR level of a product to the Federal Communications Commission (FCC) and list it on their websites and in cell phone user manuals. In the United States, the maximum amount allowed, based on a phone operating at its highest power, is 1.6 watts per kilogram of body weight.
Studies on the effects of RF exposure have taken place in labs with animals, and others have compared cancer rates in groups of people exposed to cell phones and those not exposed, or among cell phone users with and without tumors. Others are following large numbers of people for years to determine if the risks differ between those who do and those who don’t use cell phones, but many experts believe it’s too soon to come to conclusions, as the effects may take a long time to manifest.
Regardless, with Dr. Samet at its helm, The Working Group for the International Agency for Research on Cancer of the World Health Organization (WHO) released a report in 2011 saying that cell phone use may “possibly be carcinogenic to humans.” The committee reasoned that one large international study showed a possible link between heavy cell phone use and risk for glioma, although the evidence wasn’t conclusive.
Study limitations are still too numerous to end the controversy. People and their use of cell phones haven’t been followed for long enough periods of time, most studies rely on participants’ memories about cell phone use, and cell phones have only been widely used in the last 20 years. Children, who will eventually show the highest rates of use — and who, according to David Carpenter, director of the Institute for Health and Environment at the University of Albany, may be more sensitive to radiation — have not been widely included in studies. The bottom line is that confirming rare but dangerous effects requires very large numbers of people followed for long periods of time with accurate data gathering. Until such information is available, the harms associated with cell phones may be of concern, but will remain speculative.
Those who want to be cautious can keep phones farther from their bodies by using hands-free devices or earpieces, replacing talking with texting or interspersing land line use with cell phone use.
Under the advisement of Joel Moskowitz, director and principal investigator at the Center for Family and Community Health at the University of California, Berkeley, School of Public Health, the city of Berkeley last year adopted a “right to know” law requiring retailers to notify customers to read manufacturers’ RF safety information.
To reinforce what Moskowitz and colleagues consider “deleterious effects from cell phone and wireless radiation exposure,” he and 216 other scientists involved in research on electromagnetic fields and biology recently signed The International Electromagnetic Field Scientist Appeal (EMFscientist.org), a petition calling on world leaders to adopt stronger regulation of wireless radiation and to issue health warnings