It’s understandable you might be concerned that regularly talking on a cellphone could increase your risk of developing a brain tumor, as study results suggesting an association between cellphone use and brain abnormalities have made the news from time to time. And cellphones do emit radiofrequency electromagnetic fields. Those fields have been ubiquitous ever since the invention of the radio and television, but when cellphones are held to the ear, their low-energy radiofrequency waves penetrate the head by at least an inch, get absorbed by brain tissue, and can cause slight heating of that tissue in the process.
Despite how ominous that sounds, the preponderance of evidence to date suggests that cellphone use is not a danger to health. And the latest study on the subject, published just this year, provides further evidence of safety.
Published in the Journal of the National Cancer Institute in March, the study followed almost 800,000 women participating in the UK’s Million Women Study. All were born between 1935 and 1950. Looking at the data on the women’s cellphone use in 2001 and 2011, the investigators found that those who had used cellphones for at least a decade were no more likely to end up with a brain tumor than those who had never used them. This was true for women with malignant tumors like glioblastomas, which have very poor prognoses, as well as for women with noncancerous tumors.
Even the parts of the brain closest to where the phone is typically held—the temporal and parietal lobes—were not more prone to tumor development among women who talked on cellphones. Furthermore, the incidence of brain tumors was no higher on the right side of the brain than the left, even though most people tend to hold the phone up to their right ear.
Despite the reassuring results, there are caveats.
- No woman in the study was born later than 1950. That means it’s possible the findings don’t apply to young and middle-aged people, for whom landlines may be obsolete and cellphones are their primary means of talking to others. Indeed, some women in the category of highest cellphone use in the study may have used their mobile devices for as little as 20 minutes per week. But the researchers point out that more recent generations of wireless technologies emit substantially lower output power than older phones—a heavy cellphone user today is unlikely to have the same exposure to radiofrequency electromagnetic fields as a heavy cellphone user back when the technology first came into use.
- There has been a 60 percent increase in the number of brain tumors diagnosed since the 1970s, according to the study authors. But before you blame cellphones, keep in mind that the increase is likely due to improved diagnostics. In other words, it’s not that more brain tumors are developing—it’s that more of them are being found.
We should note that some research has suggested a relationship between cellphone use and brain tumor development. For instance, a project called INTERPHONE, conducted among cellphone users in 13 countries more than 10 years ago, found that people who talked on their cellphones at least 30 minutes a day appeared to be at moderately increased risk for a certain type of brain tumor called a glioma. But the INTERPHONE researchers themselves raised questions about their findings—citing potential flaws in the study design and data collection—and disagreed about the study’s implications. (The same study suggested that in certain instances, talking more frequently on a cellphone is protective against brain tumor development, a result for which there is no medical explanation.)
Also of note, a series of smaller studies conducted in Sweden saw a strong correlation between cellphone use and brain tumors even shortly after beginning to use a cellphone—a result that is not biologically plausible and, if it were, would have resulted in a massive epidemic of brain tumors throughout the world by now.
Most studies suggest little to no increase in brain tumor development among people who talk on cellphones, like one on more than 350,000 people in Denmark that found no relationship between cellphones and brain tumor development after using them for 13 years.
BOTTOM LINE: The preponderance of evidence suggests that cellphone use is not something to worry about when it comes to an increased risk of brain cancer. But if you remain concerned, there are easy solutions. For example, wear headphones when talking on your cellphone so that it is away from your head. Or use the speaker function so the phone doesn’t have to be right by your ear.