Cellphones and brain cancer: A World Health Organization review of 63 studies finds no link

A review commissioned by the World Health Organization into the potential risks of cellphone radiation has found no connection between cellphone use and brain cancer, even for people who spend all day glued to their smartphone.

Eleven experts from 10 countries pored over several decades of scientific research to reach their conclusion on a hot-button topic for health experts and regulators. They looked at 5,000 studies published between 1994 and 2022, narrowing in on 63 for their final analysis published Tuesday.

Here’s what you should know about smartphones and cancer.

What do the researchers say?

The panel of experts looked into whether there was any link between cancer and increased exposure to radio frequencies commonly used by wireless electronics, including cellphones.

They found the risk of brain cancer did not increase, even with prolonged cellphone use (defined as 10 years or more), among those who spent a lot of time on their cellphones, or for people who made a lot of calls. They also found no increased risks of leukemia or brain cancer in children exposed to radio or TV transmitters or cellphone towers.

“These results are very reassuring,” Ken Karipidis, a lead author of the review, told reporters. Cellphone use has “skyrocketed,” said Karipidis, who works for Australia’s radiation and nuclear protection authority, but “there has been no rise in the incidence of brain cancers.”

Why were cellphones considered a risk?

The International Agency for Research on Cancer, the WHO’s cancer agency, classified radio wave exposure as a possible carcinogen to humans in 2011 - based on limited evidence from observational studies. Cellphones - along with WiFi networks, radio stations, remote controls and GPS - use these invisible radio energy waves to transmit calls and text messages.

The WHO categorization doesn’t mean that radio waves are a definite carcinogen - like the chemicals in cigarette smoke - Karipidis said. He noted talcum powder and aloe vera are also considered possible carcinogens, based on limited evidence. Since then, a “lot more studies have come out” on radio waves and they’ve been “quite extensive,” he said, prompting the WHO to commission the latest review.

Karipidis said the problem with some of the early research was that it relied on case-control studies that compared the responses of people with brain cancer against those without the disease - which can be “somewhat biased.” He said a person with a brain tumor “wants to know why they’ve got the brain tumor and tends to overreport their exposure.” More comprehensive cohort studies “haven’t shown those sort of associations,” he added.

What about cellphone towers?

Cell towers, which shuttle phone calls and text messages around the world using radio energy waves, are also not a cancer risk, the researchers concluded.

Newer generation mobile networks, including third- and fourth-generation, or 3G and 4G, actually produce “substantially lower” radio frequency emissions than older networks, said Mark Elwood, an honorary professor of cancer epidemiology at the University of Auckland and a co-author of the review.

“There are no major studies yet of 5G networks, but there are studies of radar, which has similar high frequencies; these do not show an increased risk,” he said.

Karipidis said that having more cellphone towers actually reduces the amount of radiation emitted from cellphones, because they don’t have to work as hard to get a signal.

Keith Petrie, a University of Auckland expert who was not involved in the review, said that “worries about the health effects of new technology are common and tend to increase when a new technology is adopted widely or adopted quickly. This was seen during the covid-19 pandemic when people attacked cell towers believing a baseless theory that 5G towers spread the coronavirus.”

He added that the WHO-commissioned report was “a very comprehensive review by an esteemed international group.”