Cell phone use does not appear to increase the risk of brain cancer, according to a large-scale study led by the World Health Organization (WHO).
Mobile phones emit non-ionizing radiation at frequency and energy levels low enough not to damage DNA, unlike the ionizing radiation found in medical X-rays and the Sun, research has found.
Despite the rise in popularity of cell phones and other wireless technologies that use similar radio frequencies (such as radio, television and baby monitoring devices), there has been no similar increase in the incidence of three types of brain cancer, leukemia or cancers of the pituitary or salivary glands, according to this analysis, which reviewed 63 studies over two decades and was published Tuesday in the journal Environmental International.
“We found no increased risk even over 10 years of exposure and in the highest categories of call time or number of calls,” said Mark Elwood, co-author of the study and honorary professor of cancer epidemiology at the University of Auckland in New Zealand, in a statement.
Led by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), the research also examined more than 5,000 studies from which the most scientifically rigorous were identified; weak studies were excluded.
The final analysis included 63 observational human studies published between 1994 and 2022, making it “the most comprehensive review to date,” said Professor Ken Karipidis, lead author of the research, in an interview with The Guardian newspaper.
“We concluded that the evidence does not show a link between mobile phones and brain cancer or other head and neck cancers,” he explained.
Published on Tuesday, the review focused on cancers of the central nervous system (including the brain, meninges, pituitary gland and ear), salivary gland tumors and brain tumors.
The analysis found no overall association between phone use and cancer, no association with prolonged use (whether people use the mobile phone for 10 years or more), and no association with the amount of mobile phone use (the number of calls made or time spent on the phone).
“I am pretty confident in our conclusion. And what makes us pretty confident is that… even though mobile phone use has skyrocketed, brain tumor rates have remained stable,” Karipidis said.
Why are phones linked to cancer?
Cell phones—like everything that uses wireless technology, including laptop computers, radio and television transmissions, and cell phone towers—emit radio frequency electromagnetic radiation (i.e., radio waves).
Karipidis, who is vice-chair of the International Commission on Non-Ionizing Radiation Protection, said people hear the word radiation and assume it is similar to nuclear radiation.
“And because we use our cellphones close to our heads when we make calls, there is a lot of concern,” Karipidis said. “Radiation is basically energy that travels from one point to another. There are many different types, for example, ultraviolet radiation from the sun,” he said.
“We are always exposed to low-level radio waves in our everyday environment,” he added.
The link between cell phones and cancer emerged from early studies in which researchers studied the differences between a group of people with brain tumors and a group without cancer, asking both about their exposure history. According to Karipidis, the results of such studies tend to be biased, because while the group without tumors provides good information, the group with tumors tends to overreport their exposure.
The WHO’s International Agency for Research on Cancer (IARC), based on some of these early studies showing a possible link to brain cancer from using mobile phones against the head for long hours, designated radiofrequency fields such as those from mobile phones as a possible cancer risk.
Karipidis said that while many citizens were concerned about the IARC classification, “this classification does not mean much.”
According to the expert, the classification does not mean that radio waves are a definitive carcinogen, like chemicals in cigarette smoke. He noted that talcum powder and aloe vera are also considered possible carcinogens, based on limited evidence. Since then, “many more studies” on radio waves have appeared and have been “quite extensive,” he said, leading the WHO to commission the latest review.
Karipidis said the problem with some of the early research was that it was based on case-control studies comparing responses in people with brain cancer to those without the disease, which can be “somewhat biased.” She said a person with a brain tumor “wants to know why they have the brain tumor and tends to exaggerate their exposure.” More extensive studies “have not shown those kinds of associations,” she added.
What about cell phone towers?
The researchers concluded that cell phone towers, which transmit phone calls and text messages around the world using radio waves, also do not pose a cancer risk.
Newer-generation mobile networks, including third- and fourth-generation (3G and 4G), actually produce “substantially lower” radiofrequency emissions than older networks, Mark Elwood, an honorary professor of cancer epidemiology at the University of Auckland and a co-author of the study, told The Washington Post.
“There are no major studies on 5G networks yet, but there are studies on radar, which has similar high frequencies; these do not show an increase in risk,” he said.
Keith Petrie, an expert at the University of Auckland who was not involved in the review, said that “concerns about the health effects of new technologies are common and tend to increase when a new technology is widely or rapidly adopted.” This was seen during the COVID-19 pandemic, when people attacked mobile phone towers believing the unfounded theory that 5G towers spread the coronavirus.
He added that the WHO-commissioned report was “a very comprehensive review by an esteemed international group.”
With information from The Washington Post, The Guardian and Newsweek
